Customer Edge as a Fallback for F5 Distributed Cloud Regional Edge
Introduction F5 Distributed Cloud Regional Edges (REs) form the backbone of F5’s globally distributed application delivery network. These F5-managed Points of Presence handle load balancing, Web Application Firewall (WAF) enforcement, bot protection, and API security for thousands of organizations worldwide. While F5 Regional Edges are engineered for extreme resilience—with built-in redundancy, geographic distribution, and continuous monitoring—no infrastructure is entirely immune to disruption. A defense-in-depth strategy demands that organizations consider even low-probability scenarios. This article explores how F5 Distributed Cloud Customer Edge (CE) nodes can serve as a fallback data path in the unlikely event of a Regional Edge outage, leveraging a capability that many organizations already have deployed but may not have considered for this purpose. Understanding the RE and CE Data Paths Regional Edge: The Default Path In a typical F5 Distributed Cloud deployment, application traffic follows this path: Client resolves the application’s FQDN via DNS DNS returns an F5 Regional Edge Anycast IP address Internet BGP routing directs the client to the nearest RE advertising that IP The RE terminates the connection, applies load balancing and security policies The RE forwards traffic to origin servers (directly or via CE nodes) The key mechanism here is IP Anycast. F5 Regional Edges advertise the same unicast IP address from multiple Points of Presence worldwide via BGP. When a client sends traffic to that IP, the internet’s BGP routing infrastructure naturally selects the shortest AS path—effectively directing the client to the geographically closest (or topologically nearest) RE. This means the DNS itself does not perform geographic selection. Every client worldwide receives the same IP address in the DNS response. It is the underlying BGP routing on the internet that ensures each client reaches its nearest RE. This is a fundamental difference from GeoDNS-based approaches, where different IPs are returned depending on the client’s location. Anycast routing typically delivers lower and more consistent latency than GeoDNS for several reasons: BGP routes on network topology, not geographic approximation. BGP is a path-vector protocol that selects routes based on AS path length, local preference, and policy attributes—not latency or congestion. However, in practice, routing to the topologically nearest PoP (fewest AS hops) generally correlates with reasonable latency, even if it is not optimized for it. GeoIP databases are approximations. GeoDNS relies on commercial GeoIP databases to map IP addresses to locations. These databases can be inaccurate or outdated. BGP doesn’t care about IP-to-location mapping; it routes based on actual network reachability. BGP adapts in real-time. If a link fails or a PoP goes offline, the BGP reconverges and traffic shifts to the next-best path automatically—often within seconds. GeoDNS is static until the DNS TTL expires. During that window, clients may continue hitting a degraded or unreachable endpoint. Regional Edges operate as a fully managed SaaS infrastructure. Organizations benefit from F5’s global Anycast network without deploying or maintaining edge nodes themselves. Customer Edge: The On-Premises Path Customer Edge nodes, typically deployed in on-premises data centers or customer cloud environments, can provide the same load balancing and WAF capabilities as Regional Edges. This is a critical but often underappreciated architectural property of the F5 Distributed Cloud platform. When a load balancer is configured in the F5 Distributed Cloud Console, it can be advertised on: Regional Edges only — the default for internet-facing applications Customer Edges only — common for internal applications Both Regional Edges and Customer Edges — the key to the fallback strategy described in this article The Shared Configuration Principle A single load balancer object in the F5 Distributed Cloud Console—with its full configuration including WAF policies, routes, rate limiting, and origin pools—can be advertised simultaneously on REs and CEs. There is no need to duplicate or maintain separate configurations. Aspect Regional Edge Customer Edge Load Balancing ✓ Same configuration ✓ Same configuration WAF / App Firewall ✓ Same policies ✓ Same policies Routes and Rewrites ✓ Same rules ✓ Same rules Origin Pool Selection ✓ Same pools ✓ Same pools Bot Defense ✓ ✓ API Protection ✓ ✓ Managed by F5 Customer Key Insight: This configuration parity is the foundation of the fallback strategy. The same security posture is enforced regardless of whether traffic enters through a RE or a CE. The Fallback Strategy: DNS-Based Traffic Switching How It Works The failover mechanism from Regional Edges to Customer Edges relies on a straightforward DNS change. Under normal operation, the application's DNS record points to the RE-assigned IP addresses. In a fallback scenario, the DNS record is updated to point to the public IP addresses of the Customer Edge nodes. Normal Operation: app.example.com → RE Anycast IP (e.g., 5.x.x.x, same IP globally) → BGP routing directs client to nearest Regional Edge → RE applies LB + WAF policies → RE forwards to origin Fallback Operation: app.example.com → CE Public IP (e.g., 203.0.113.10, standard unicast) → Client connects directly to Customer Edge (no Anycast routing) → CE applies the SAME LB + WAF policies → CE forwards to origin The application experience remains identical from the client's perspective in terms of security and functionality. The same policies are enforced, the same load balancing decisions are made, and the same origins are reached. The trade-off is that clients lose the Anycast proximity benefit—all traffic converges on the CE location(s) rather than being distributed to the nearest PoP. Prerequisites Before this strategy can be activated, several elements must be in place: The load balancer must be advertised on both REs and CEs. This is configured in the F5 Distributed Cloud Console under the load balancer's VIP advertisement settings. The CE advertisement must be active before an incident—configuring it during an outage adds delay and risk. The “Virtual Network“ type with value “ves-io-shared/public” is the equivalent of “Internet“ VIP advertisement. CE nodes must have public IP reachability. The CE's outside interface (or an NAT/firewall in front of it) must be reachable from the internet on the required ports (typically 443 and/or 80). This may require firewall rules, NAT configurations, or public IP assignments that should be validated in advance. CE nodes must have sufficient capacity for degraded-mode operation. Under normal operation, REs handle the full internet-facing traffic load. CEs used as fallback must be sized to sustain this traffic temporarily—long enough to bridge a RE outage, not to replace RE infrastructure indefinitely. This includes compute resources (CPU, memory), network bandwidth at the CE site, and upstream internet connectivity. DNS records must be prepared. The target CE IP addresses should be documented and ideally pre-staged in DNS management tooling so that the switchover can be executed rapidly. Important: All prerequisites must be validated before an incident occurs. A fallback strategy that hasn’t been tested is not a fallback strategy. Customer Edge: The On-Premises Path Customer Edge nodes, typically deployed in on-premises data centers or customer cloud environments, can provide the same load balancing and WAF capabilities as Regional Edges. This is a critical but often underappreciated architectural property of the F5 Distributed Cloud platform. When a load balancer is configured in the F5 Distributed Cloud Console, it can be advertised on: Regional Edges only — the default for internet-facing applications Customer Edges only — common for internal applications Both Regional Edges and Customer Edges — the key to the fallback strategy described in this article The Shared Configuration Principle A single load balancer object in the F5 Distributed Cloud Console—with its full configuration including WAF policies, routes, rate limiting, and origin pools—can be advertised simultaneously on REs and CEs. There is no need to duplicate or maintain separate configurations. Aspect Regional Edge Customer Edge Load Balancing ✓ Same configuration ✓ Same configuration WAF / App Firewall ✓ Same policies ✓ Same policies Routes and Rewrites ✓ Same rules ✓ Same rules Origin Pool Selection ✓ Same pools ✓ Same pools Bot Defense ✓ ✓ API Protection ✓ ✓ Managed by F5 Customer Key Insight: This configuration parity is the foundation of the fallback strategy. The same security posture is enforced regardless of whether traffic enters through a RE or a CE. DNS TTL: The Critical Factor Why TTL Matters The speed of a DNS-based failover is fundamentally governed by the Time-To-Live (TTL) value set on the application’s DNS records. TTL determines how long DNS resolvers and clients cache a DNS response before querying again. TTL Value Effective Switchover Time Trade-off 3600 (1 hour) Up to 1 hour Minimal DNS query load, slow failover 300 (5 minutes) Up to 5 minutes Moderate query load, reasonable failover 60 (1 minute) Up to 1 minute Higher query load, fast failover 30 (30 seconds) Up to 30 seconds Significant query load, near-instant failover Critical: TTL must be set before an incident occurs. Lowering TTL during an outage has no effect on records already cached by resolvers worldwide. The old, higher TTL continues to govern those cached entries until they expire naturally. Recommended Approach For organizations that consider CE fullbacks as part of their resilience strategy: Proactive TTL reduction: Set DNS TTL to 60–300 seconds on records that may need failover. This should be steady-state TTL, not an emergency change. Pre-incident preparation: Ensure the DNS change procedure is documented, tested, and can be executed by on-call staff within minutes. Automated failover (advanced): Integrate health checks on RE endpoints with DNS automation (via API calls to your DNS provider) to trigger the switch automatically. The TTL Reality Check Even with low TTL values, some clients and intermediate resolvers do not strictly honor TTL: Stub resolvers on end-user devices may cache beyond the stated TTL Some enterprise DNS resolvers impose minimum TTL floors (commonly 30–60 seconds) Browser DNS caches may hold entries independently of the OS resolver Connection keep-alive means existing TCP/TLS sessions continue to the old IP even after DNS changes Organizations should expect a gradual migration of traffic rather than an instantaneous cutover, even with aggressive TTL values. Plan for a transition window of several minutes during which traffic flows to both the old and new endpoints. Operational Caveats and Considerations Capacity Planning Under normal operations, Regional Edges absorb the full internet-facing traffic load across F5’s globally distributed infrastructure. Switching to Customer Edges concentrates this traffic onto a much smaller set of nodes, typically in one or two locations. Factor Regional Edges Customer Edges (Fallback) Geographic distribution Global Limited (customer sites) Bandwidth F5 backbone Customer uplink DDoS absorption F5 scrubbing capacity Customer/ISP capacity Horizontal scale Elastic Fixed (pre-provisioned) Recommendation: Conduct periodic load testing against CE nodes to validate they can sustain the expected RE traffic volume for a limited duration. CE infrastructure does not need to match RE capacity long-term, but it must hold up long enough to bridge an outage window without service degradation. DDoS Protection F5 Regional Edges benefit from F5’s network-level DDoS mitigation infrastructure. When traffic is redirected to Customer Edge nodes, this protection layer is bypassed. The CE site’s internet uplink becomes the direct target for any volumetric attack. Mitigation options: Ensure the CE site has upstream DDoS protection from the ISP or a dedicated scrubbing service Consider maintaining a DDoS-protected IP transit for CE public addresses If using BGP-routed DDoS protection, ensure CE public prefixes are covered Failover Workflow When a RE outage is confirmed and the decision to fail over is made, the procedure is: Step 1: Update DNS Records Change the application’s DNS A record (or AAAA for IPv6) from the RE IP addresses to the CE public IP addresses. If multiple CEs are available, configure multiple A records or use the BGP/ECMP architecture described in Part One of this series to distribute traffic across CEs behind a single public IP. Step 2: Monitor the Transition Observe traffic shifting to CEs as DNS caches expire. Expect a gradual ramp-up over a period aligned with your DNS TTL. Monitor CE resource utilization, error rates, and application response times. Step 3: Restore Normal Operation Once RE services are restored, reverse the DNS change to point back to RE IP addresses. Again, the transition back follows the same TTL-governed timeline. Validate that traffic has fully returned to the RE path before considering any CE-specific fallback infrastructure changes. Conclusion F5 Distributed Cloud Customer Edges provide a credible fallback path for the unlikely scenario of a Regional Edge outage. The platform’s ability to advertise a single load balancer—with identical configuration, WAF policies, and origin pools—on both REs and CEs is the enabling feature that makes this strategy viable without configuration duplication or drift. The key success factors are preparation and proactive configuration: DNS TTL must be set low before an incident, not during one CE capacity must be sufficient to handle traffic load in a degraded mode—this is a temporary measure, not a long-term replacement for RE infrastructure The full failover procedure must be tested periodically to remain viable Operational caveats—latency, DDoS exposure, session interruption—must be understood and accepted as part of the failover trade-off This approach does not replace the resilience built into F5’s Regional Edge infrastructure. Rather, it provides an additional layer of organizational confidence: even in a worst-case scenario, the application delivery path can be restored using infrastructure the organization already controls.AI-Enabled Risk Scoring Helps Reduce Risks
Risk Categories AI-enabled Risk Scoring for F5 Distributed Cloud WAF reduces key risk categories: Security, Business/availability, and Operational. Security risk (missed attacks / false negatives): F5 Distributed Cloud's AI-Powered WAF Risk Scoring improves detection by combining multiple signals per request so you don't miss attacks that traditional WAFs may not catch: High-confidence signatures Curated signature combinations (with LLM labeling to improve precision) Attack indicators (e.g., SQLi signals, libinjection, multiple signatures) A real-time ML model—to catch attacks that traditional WAFs may miss Business/availability risk (false positives blocking real users) By assigning High/Medium/Low risk outcomes using layered analysis, teams can enforce blocking with more confidence and keep false positives low, reducing accidental customer impact such as blocking legitimate users. Staged workflows are enabled, such as: Block High Review Medium (implicitly allow Low while continuing to observe) Operational risk (slow time-to-protection and heavy tuning burden) F5 Distributed Cloud's AI-Powered WAF Risk Scoring reduces manual exceptions and case-by-case policy tuning, enabling teams to deploy the WAF in blocking mode sooner, with less ongoing friction across SecOps, dev, and platform teams. Outcome-based scoring enables: Improved consistency of enforcement across distributed apps/APIs Standardization of protection by reducing bespoke tuning per app How the system makes a risk decision Risk level is computed from layering multiple complementary analyses: High Risk or High Accuracy Signature matches Heuristics – such as injection attacks, multiple attack signatures detected, predictable resource exploitation, other risk indicators Neural network - Signatures can sometimes lead to false positives. To address that, a neural network acts as a secondary classifier to determine whether attack fragments flagged by signatures signal an attack, improving accuracy while maintaining real-time performance. Key system scope The ML model analyzes behavioral patterns to refine risk assessment, ensuring accurate classification and enabling effective threat prioritization. Calling the ML model will adhere to the following scope: The ML model is called only if at least one enabled (not excluded/disabled) signature triggers in these categories: Server-Side Code Injection, SQL Injection, XSS, Command Execution, Path Traversal, LDAP Injection, XPath Injection The model analyzes only HTTP request fragments that trigger signatures (not full raw requests). If signatures are excluded or disabled, they are not considered for invoking the model. Model output: 1 = malicious → request risk level set to High 0 = benign → request risk level set to False Positive A primer on Signature Accuracy vs Signature Risk Accuracy Indicates the ability of the attack signature to identify the attack including susceptibility to false-positive alarms: Low: Indicates a high likelihood of false positives. Medium: Indicates some likelihood of false positives. High: Indicates a low likelihood of false positives. Risk Indicates the level of potential damage this attack might cause if it is successful: Low: Indicates the attack does not cause direct damage or reveal highly sensitive data. Medium: Indicates the attack may reveal sensitive data or cause moderate damage. High: Indicates the attack may cause a full system compromise. Does AI-enabled Risk Scoring add latency? AI-enabled Risk Scoring works in line with F5 Distributed Cloud WAF, inspecting real-time traffic without adding noticeable latency in our tests.Implementing Risk-Based Actions with AI-Powered WAF: Customer Policy Paths
Why Custom policy is where risk-based actions matter most The default policy is straightforward: it applies a broad mix of signatures, threat campaigns, and violations; “Enhance with AI” is an optional add-on. Custom policies are where customers can accidentally recreate the same problems Risk Scoring is designed to solve—usually by combining: Overly broad/noisy signature selection (especially low-accuracy signatures) Aggressive enforcement (blocking Medium too early) Disabling/excluding key signatures and unintentionally reducing ML invocation So the rest of this blog is a tight, configuration-oriented walkthrough of the Custom path. Custom policy: configuration walkthrough (decision points → operational outcomes) Baseline: Navigate to the Custom controls LB Config → Web Application Firewall Create/edit the WAF object (Metadata `Name`, etc.) Set Security Policy = Custom Choose Signature Selection by Accuracy Optionally enable Enhance with AI (Risk Scoring) If enabled, optionally configure Action by Risk Score (risk-based enforcement) Step 1: Signature Selection by Accuracy (choose your baseline level) Accuracy indicates susceptibility to false positives: Low: high likelihood of false positives Medium: some likelihood of false positives High: low likelihood of false positives Note: This setting is foundational: it determines which signatures are active, and therefore the quality and volume of detection signals that feed into downstream risk evaluation. Operationally: High accuracy tends to support faster, safer enforcement. Medium/Low accuracy can expand coverage but increases the chance you’ll need exceptions, investigations, or staged rollout discipline. Step 2: Enhance with AI (turn on Risk Scoring) Enhance with AI = On enables AI-powered risk scoring and assigns each request a High/Medium/Low risk score using layered signals. Two implementation details to make explicit in your blog because they affect customer expectations: ML invocation depends on enabled signatures firing in the specified injection/execution categories. If teams disable/exclude those signatures, they may reduce when the model runs—changing practical behavior of risk evaluation. Step 3: Action by Risk Score (map risk levels to enforcement) When Action by Risk Score is enabled: By default, high-risk requests are blocked Users can choose whether Medium-risk requests are blocked (via dropdown) This is the primary knob that determines how quickly a user decides to move from “safe enforcement” to “broad enforcement.” Recommended rollout path: Day 0 → Day 7 → Steady state This is the most common and safest operational progression for customers Day 0 (safe enforcement baseline) Custom → Signature Selection by Accuracy = High (or High + Medium if you need broader coverage immediately) Enhance with AI = On Action by Risk Score = High Outcome Gets to blocking quickly while minimizing availability risk. High is blocked. This is the “prove safety while stopping obvious bad” posture. Day 7 (controlled expansion) Keep Custom + Enhance with AI + Action by Risk Score Optionally widen Signature Selection from High → High + Medium if coverage is insufficient Enhance with AI = On Action by Risk Score = High + Medium Outcome Expands detection inputs without immediately expanding enforcement. Teams focus on what’s landing in Medium and whether exclusions/disabled signatures are reducing ML invocation in key categories Steady state (mature enforcement) Custom → signature selection set to the broadest set Widen Signature Selection from High + Medium → High + Medium + Low Action by Risk Score = High + Medium Enhance with AI = On Action by Risk Score = High + Medium Outcome Risk outcomes become the enforcement interface. Broad, consistent blocking across apps/APIs with reduced per-app tuning and fewer signature-level decisions Common Pitfalls: Avoid Block Medium on Day 0 when including low-accuracy signatures—this is the fastest way to recreate false-positive outages. If you disable/exclude signatures in the key injection/execution categories, you can reduce ML invocation and change risk evaluation behavior. Summary Custom policies traditionally scale poorly because every app ends up with bespoke signature decisions and exception handling. Risk Scoring is designed to invert that: keep signatures as key signals but standardize enforcement via risk outcomes. If you implement Custom with the Day 0 → Day 7 → Steady state progression above, you get a predictable path from “block safely now” to “enforce broadly later” without returning to signature-by-signature tuning as your primary operating model.F5 Distributed Cloud – Why You Should Never Block Regional Edge IPs on Your Firewall
Introduction A common mistake when onboarding a public-facing application onto F5 Distributed Cloud (XC) is to restrict which source IP addresses can reach the origin server. Network and security teams, following a traditional “deny all / allow what you need” approach, sometimes allow only a handful of F5 XC Regional Edge IPs through their firewall — or worse, block RE IPs entirely because they see unfamiliar traffic hitting the origin from IP ranges they don’t recognize. This article explains why this is fundamentally incompatible with how F5 Distributed Cloud works, and what the consequences are. Understanding Distributed Architecture When you expose an application through F5 Distributed Cloud, the platform advertises your application’s FQDN via an Anycast IP address across all Regional Edges worldwide. As of the latest updates, this means your application is reachable through multiple REs across the Americas, Europe, and Asia-Pacific. Each RE acts as an independent proxy and point of presence. End users are routed to the closest RE based on BGP peering and network proximity. This is the core of F5 XC’s distributed model — there is no single centralized proxy. How Health Checks Work: Each RE Monitors Independently This is the critical point that is often misunderstood. When you configure a Health Check and an Origin Pool with your application’s public IP, every Regional Edge independently performs its own health check against your origin server. Each RE uses its own local internet breakout to reach your application — health check traffic does not traverse the F5 Global Network. This means: If you have an origin server with a public IP, and your Origin Pool is configured with “Public IP” (the default), then all REs will send health-check probes to your origin. Each RE maintains its own independent view of your origin’s health status. On the F5 XC console, you will see the same origin IP listed multiple times — once per RE — each with its own health status. The source IPs of these health checks come from the RE subnet ranges published in the official F5 documentation: F5 Distributed Cloud IP Address and Domain Reference. What Happens When You Block Some RE IPs Suppose you allow only a few RE IP ranges (for example, only European REs) but block the rest. Here is what happens: REs whose IPs are allowed will successfully complete health checks, and your origin will appear as UP from those locations. REs whose IPs are blocked will see health check failures, and your origin will be marked as DOWN from those locations. The immediate and most visible consequence is on the F5 XC console itself. Because a majority of REs report the origin as DOWN, the console will display a degraded application health status — showing poor availability and performance metrics. This gives a misleading picture of your application’s actual state: your origin is perfectly healthy, but the console reflects a largely unhealthy deployment simply because most REs cannot reach it through the firewall. This can trigger unnecessary troubleshooting, false alerts, and erode confidence in the platform’s monitoring data. Now, when an end user connects through a blocked RE (for example, a user in Asia hitting a Singapore RE), the platform behavior depends on the Endpoint Selection policy configured in your Origin Pool: Endpoint Selection Policy Behavior When Local RE Shows Origin as DOWN Local Endpoints Only Traffic is dropped. The user gets an error. No fallback. Local Endpoints Preferred (default) Traffic is forwarded via the F5 Global Network to a RE that has the origin marked as UP. This adds some latency. All Endpoints Same as Local Preferred — traffic is rerouted to a healthy RE over the Global Network. This can add major latency if the responding RE is far away from the origin. In the Local Endpoints Only case, users connecting through blocked REs will experience a complete outage for your application — even though the origin is healthy and reachable. In the Local Preferred or All Endpoints cases, the platform will attempt to reroute traffic through the F5 Global Network to a RE that has a healthy view of the origin. While the application will still be reachable, this introduces several problems: Increased latency: Traffic must travel from the ingress RE to a remote egress RE over the internal F5XC fabric before reaching your origin, instead of egressing locally to the internet. Suboptimal routing: A user in Tokyo may end up having their traffic routed through Paris because only European REs can reach the origin — defeating the purpose of a globally distributed edge. Reduced resilience: You’ve effectively reduced the number of egress points that can serve traffic, creating bottlenecks and potential single points of failure. The Correct Default Approach: Allowlist All RE IP Ranges The F5 official documentation is clear on this point: you should allowlist all F5 Distributed Cloud RE subnet ranges on your origin firewall. The published IP ranges are organized by region (Americas, Europe, Asia) and are available on the official F5 Distributed Cloud documentation page. Ideally, your origin firewall should be configured to only allow the F5 Distributed Cloud subnets for your application’s listening port. This ensures that: All RE health checks succeed, giving the platform an accurate and complete view of your origin’s health. Traffic egresses locally from the closest RE, providing the lowest latency path to your users. Only traffic routed through F5 XC can reach your origin, preventing attackers from bypassing the F5 XC security stack (WAAP, DDoS, Bot Protection, etc.) by hitting the origin directly. What If You Want to Limit Which REs Perform Health Checks? If you have a legitimate reason to reduce the number of REs performing health checks (for example, to reduce health check traffic on the origin or because your application is regionally scoped), F5 XC provides a built-in mechanism for this. Instead of using “Public IP” in the Origin Pool member configuration, select “IP Address of Origin Server on Given Sites” and then assign a Virtual Site that includes only the REs you want. For example, you could create a Virtual Site that includes only European REs, reducing your health check sources from all worldwide REs down to just the ones in that region. Conclusion F5 Distributed Cloud is architected as a fully distributed system. Health monitoring is not performed from a central location — it is performed independently by every Regional Edge. This design is what enables the platform to provide low-latency, resilient application delivery worldwide. Blocking RE IPs on your origin firewall fundamentally breaks this distributed health monitoring model. It causes health checks to fail, triggers suboptimal traffic routing, and potentially increases latency. The correct and recommended approach is to allowlist all F5 Distributed Cloud RE IP ranges on your origin firewall, and use the platform’s built-in Virtual Site mechanism if you need to control which REs perform health checks.Bulk-Create Secondary DNS Zones in F5 Distributed Cloud (via API)
If you’ve ever had to onboard dozens (or hundreds) of domains as secondary DNS zones in F5 Distributed Cloud (XC), you know the drill: click through the console, fill in the domain, add the primary server IP, save, repeat. It works - but it doesn’t scale. I ran into exactly this situation recently and figured a quick shell script would save me (and maybe you) a lot of clicking. What it does The script reads a simple text file - one domain per line, comma-separated with its primary DNS server IPs - and creates the corresponding secondary DNS zones via the F5 XC API. The input file looks like this: example.com, 10.0.0.1, 10.0.0.2 example.org, 192.168.1.1 internal.example.net, 172.16.0.1, 172.16.0.2, 172.16.0.3 Run the script, and it works through the list one by one: $ ./create_secondary_dns.sh Starting secondary DNS zone creation... Tenant : acmecorp --- [line 1] Creating secondary zone: example.com (primaries: 10.0.0.1 10.0.0.2) [line 1] OK - example.com created (HTTP 200) [line 2] Creating secondary zone: example.org (primaries: 192.168.1.1) [line 2] OK - example.org created (HTTP 200) --- Done. Success: 2, Failed: 0, Total lines: 2 That’s it. No Python, no Terraform, no extra frameworks - just bash, curl, and jq. TSIG support If your primary DNS servers require TSIG authentication for zone transfers, the script handles that too. Set the TSIG key name, algorithm, and secret in the configuration block, and the script will encrypt the secret locally using vesctl (the F5 XC CLI) before sending it to the API. If vesctl isn’t installed yet, the script downloads it automatically. If you don’t need TSIG, just leave the TSIG variables empty and the script skips that part entirely. Getting started 1. Clone the repo and navigate to the tool: git clone https://github.com/de1chk1nd/resources-and-tools.git cd resources-and-tools/tools/dns-secondary 2. Create your domain list: cp domains.txt.example domains.txt 3. Open the script and fill in your tenant name and API token: vi create_secondary_dns.sh 4. Run it: chmod +x create_secondary_dns.sh ./create_secondary_dns.sh The full README in the repository covers all configuration options, dependencies, and common error messages. What happens when something goes wrong? The script validates every line before hitting the API - domain names are checked for valid DNS characters, IP addresses are checked for valid IPv4 format. If a line is malformed, it’s skipped with a clear message and the script moves on to the next one. If a zone already exists in XC, the API returns a 409 and the script logs it as a failure but keeps going. At the end, you get a summary: how many succeeded, how many failed. A note on the repository This is a personal project, not an official F5 tool. It’s not supported by F5 and comes with no warranty. That said, it works well for my use cases and I hope it’s useful for yours too. If you run into issues or have suggestions, please open an issue on GitHub: GIT Repo The script lives here: DNS ToolLeveraging BGP and ECMP for F5 Distributed Cloud Customer Edge, Part Two
Introduction This is the second part of our series on leveraging BGP and ECMP for F5 Distributed Cloud Customer Edge deployments. In Part One, we explored the high-level concepts, architecture decisions, and design principles that make BGP and ECMP such a powerful combination for Customer Edge high availability and maintenance operations. This article provides step-by-step implementation guidance, including: High-level and low-level architecture diagrams Complete BGP peering and routing policy configuration in F5 Distributed Cloud Console Practical configuration examples for Fortinet FortiGate and Palo Alto Networks firewalls By the end of this article, you'll have everything you need to implement BGP-based high availability for your Customer Edge deployment. Architecture Overview Before diving into configuration, let’s establish a clear picture of the architecture we’re implementing. We’ll examine this from two perspectives: a high-level logical view and a detailed low-level view showing specific IP addressing and AS numbers. High-Level Architecture The high-level architecture illustrates the fundamental traffic flow and BGP relationships in our deployment: Key Components: Component Role Internet External connectivity to the network Next-Generation Firewall Acts as the BGP peer and performs ECMP distribution to Customer Edge nodes Customer Edge Virtual Site Two or more CE nodes advertising identical VIP prefixes via BGP The architecture follows a straightforward principle: the upstream firewall establishes BGP peering with each CE node. Each CE advertises its VIP addresses as /32 routes. The firewall, seeing multiple equal-cost paths to the same destination, distributes incoming traffic across all available CE nodes using ECMP. Low-Level Architecture with IP Addressing The low-level diagram provides the specific details needed for implementation, including IP addresses and AS numbers: Network Details: Component IP Address Role Firewall (Inside) 10.154.4.119/24 BGP Peer, ECMP Router CE1 (Outside) 10.154.4.160/24 Customer Edge Node 1 CE2 (Outside) 10.154.4.33/24 Customer Edge Node 2 Global VIP 192.168.100.10/32 Load Balancer VIP BGP Configuration: Parameter Firewall Customer Edge AS Number 65001 65002 Router ID 10.154.4.119 Auto-assigned based on interface IP Advertised Prefix None 192.168.100.0/24 le 32 This configuration uses eBGP (External BGP) between the firewall and CE nodes, with different AS numbers for each. The CE nodes share the same AS number (65002), which is the standard approach for multi-node CE deployments advertising the same VIP prefixes. Configuring BGP in F5 Distributed Cloud Console The F5 Distributed Cloud Console provides a centralized interface for configuring BGP peering and routing policies on your Customer Edge nodes. This section walks you through the complete configuration process. Step 1: Configure the BGP peering Go to: Multi-Cloud Network Connect --> Manage --> Networking --> External Connectivity --> BGP Peers & Policies Click on Add BGP Peer Then add the following information: Object name Site where to apply this BGP configuration ASN Router ID Here is an example of the required parameters. Then click on Peers --> Add Item And filled the relevant fields like below by adapting the parameters for your requirements. Step 2: Configure the BGP routing policies Go to: Multi-Cloud Network Connect --> Manage --> Networking --> External Connectivity --> BGP Peers & Policies --> BGP Routing Policies Click on Add BGP Routing Policy Add a name for your BGP routing policy object and click on Configure to add the rules. Click on Add Item to add a rule. Here we are going to allow the /32 prefixes from our VIP subnet (192.168.100.0/24). Save the BGP Routing Policy Repeat the action to create another BGP routing policy with the exact same parameters except the Action Type, which should be of type Deny. Now we have two BGP routing policies: One to allow the VIP prefixes (for normal operations) One to deny the VIP prefixes (for maintenance mode) We still need to a a third and final BGP routing policy, in order to deny any prefixes on the CE. For that, create a third BGP routing policy with this match. Step 3: Apply the BGP routing policies To apply the BGP routing policies in your BGP peer object, edit the Peer and: Enable the BGP routing policy Apply the BGP routing policy objects created before for Inbound and Outbound Fortinet FortiGate Configuration FortiGate firewalls are widely deployed as network security appliances and support robust BGP capabilities. This section provides the minimum configuration for establishing BGP peering with Customer Edge nodes and enabling ECMP load distribution. Step 1: Configure the Router ID and AS Number Configure the basic BGP settings: config router bgp set as 65001 set router-id 10.154.4.119 set ebgp-multipath enable Step 2: Configure BGP Neighbors Add each CE node as a BGP neighbor: config neighbor edit "10.154.4.160" set remote-as 65002 set route-map-in "ACCEPT-CE-VIPS" set route-map-out "DENY-ALL" set soft-reconfiguration enable next edit "10.154.4.33" set remote-as 65002 set route-map-in "ACCEPT-CE-VIPS" set route-map-out "DENY-ALL" set soft-reconfiguration enable next end end Step 3: Create Prefix List for VIP Range Define the prefix list that matches the CE VIP range: config router prefix-list edit "CE-VIP-PREFIXES" config rule edit 1 set prefix 192.168.100.0 255.255.255.0 set ge 32 set le 32 next end next end Important: The ge 32 and le 32 parameters ensure we only match /32 prefixes within the 192.168.100.0/24 range, which is exactly what CE nodes advertise for their VIPs. Step 4: Create Route Maps Configure route maps to implement the filtering policies: Inbound Route Map (Accept VIP prefixes): config router route-map edit "ACCEPT-CE-VIPS" config rule edit 1 set match-ip-address "CE-VIP-PREFIXES" next end next end Outbound Route Map (Deny all advertisements): config router route-map edit "DENY-ALL" config rule edit 1 set action deny next end next end Step 5: Verify BGP Configuration After applying the configuration, verify the BGP sessions and routes: Check BGP neighbor status: get router info bgp summary VRF 0 BGP router identifier 10.154.4.119, local AS number 65001 BGP table version is 4 1 BGP AS-PATH entries 0 BGP community entries Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.154.4.33 4 65002 2092 2365 0 0 0 00:05:33 1 10.154.4.160 4 65002 2074 2346 0 0 0 00:14:14 1 Total number of neighbors 2 Verify ECMP routes: get router info routing-table bgp Routing table for VRF=0 B 192.168.100.10/32 [20/255] via 10.154.4.160 (recursive is directly connected, port2), 00:00:11, [1/0] [20/255] via 10.154.4.33 (recursive is directly connected, port2), 00:00:11, [1/0] Palo Alto Networks Configuration Palo Alto Networks firewalls provide enterprise-grade security with comprehensive routing capabilities. This section covers the minimum BGP configuration for peering with Customer Edge nodes. Note: This part is assuming that Palo Alto firewall is configured in the new "Advanced Routing Engine" mode. And we will use the logical-router named "default". Step 1: Configure ECMP parameters set network logical-router default vrf default ecmp enable yes set network logical-router default vrf default ecmp max-path 4 set network logical-router default vrf default ecmp algorithm ip-hash Step 2: Configure objects IPs and firewall rules for BGP peering set address CE1 ip-netmask 10.154.4.160/32 set address CE2 ip-netmask 10.154.4.33/32 set address-group BGP_PEERS static [ CE1 CE2 ] set address LOCAL_BGP_IP ip-netmask 10.154.4.119/32 set rulebase security rules ALLOW_BGP from service set rulebase security rules ALLOW_BGP to service set rulebase security rules ALLOW_BGP source LOCAL_BGP_IP set rulebase security rules ALLOW_BGP destination BGP_PEERS set rulebase security rules ALLOW_BGP application bgp set rulebase security rules ALLOW_BGP service application-default set rulebase security rules ALLOW_BGP action allow Step 3: Palo Alto Configuration Summary (CLI Format) set network routing-profile filters prefix-list ALLOWED_PREFIXES type ipv4 ipv4-entry 1 prefix entry network 192.168.100.0/24 set network routing-profile filters prefix-list ALLOWED_PREFIXES type ipv4 ipv4-entry 1 prefix entry greater-than-or-equal 32 set network routing-profile filters prefix-list ALLOWED_PREFIXES type ipv4 ipv4-entry 1 prefix entry less-than-or-equal 32 set network routing-profile filters prefix-list ALLOWED_PREFIXES type ipv4 ipv4-entry 1 action permit set network routing-profile filters prefix-list ALLOWED_PREFIXES description "Allow only m32 inside 192.168.100.0m24" set network routing-profile filters prefix-list DENY_ALL type ipv4 ipv4-entry 1 prefix entry network 0.0.0.0/0 set network routing-profile filters prefix-list DENY_ALL type ipv4 ipv4-entry 1 prefix entry greater-than-or-equal 0 set network routing-profile filters prefix-list DENY_ALL type ipv4 ipv4-entry 1 prefix entry less-than-or-equal 32 set network routing-profile filters prefix-list DENY_ALL type ipv4 ipv4-entry 1 action deny set network routing-profile filters prefix-list DENY_ALL description "Deny all prefixes" set network routing-profile bgp filtering-profile FILTER_INBOUND ipv4 unicast inbound-network-filters prefix-list ALLOWED_PREFIXES set network routing-profile bgp filtering-profile FILTER_OUTBOUND ipv4 unicast inbound-network-filters prefix-list DENY_ALL set network logical-router default vrf default bgp router-id 10.154.4.119 set network logical-router default vrf default bgp local-as 65001 set network logical-router default vrf default bgp install-route yes set network logical-router default vrf default bgp enable yes set network logical-router default vrf default bgp peer-group BGP_PEERS type ebgp set network logical-router default vrf default bgp peer-group BGP_PEERS address-family ipv4 ipv4-unicast-default set network logical-router default vrf default bgp peer-group BGP_PEERS filtering-profile ipv4 FILTER_INBOUND set network logical-router default vrf default bgp peer-group BGP_PEERS filtering-profile ipv4 FILTER_OUTBOUND set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE1 peer-as 65002 set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE1 local-address interface ethernet1/2 set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE1 local-address ip svc-intf-ip set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE1 peer-address ip 10.154.4.160 set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE2 peer-as 65002 set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE2 local-address interface ethernet1/2 set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE2 local-address ip svc-intf-ip set network logical-router default vrf default bgp peer-group BGP_PEERS peer CE2 peer-address ip 10.154.4.33 Step 4: Verify BGP Configuration After committing the configuration, verify the BGP sessions and routes: Check BGP neighbor status: run show advanced-routing bgp peer status logical-router default Logical Router: default ============== Peer Name: CE2 BGP State: Established, up for 00:01:55 Peer Name: CE1 BGP State: Established, up for 00:00:44 Verify ECMP routes: run show advanced-routing route logical-router default Logical Router: default ========================== flags: A:active, E:ecmp, R:recursive, Oi:ospf intra-area, Oo:ospf inter-area, O1:ospf ext 1, O2:ospf ext 2 destination protocol nexthop distance metric flag tag age interface 0.0.0.0/0 static 10.154.1.1 10 10 A 01:47:33 ethernet1/1 10.154.1.0/24 connected 0 0 A 01:47:37 ethernet1/1 10.154.1.99/32 local 0 0 A 01:47:37 ethernet1/1 10.154.4.0/24 connected 0 0 A 01:47:37 ethernet1/2 10.154.4.119/32 local 0 0 A 01:47:37 ethernet1/2 192.168.100.10/32 bgp 10.154.4.33 20 255 A E 00:01:03 ethernet1/2 192.168.100.10/32 bgp 10.154.4.160 20 255 A E 00:01:03 ethernet1/2 total route shown: 7 Implementing CE Isolation for Maintenance As discussed in Part One, one of the key advantages of BGP-based deployments is the ability to gracefully isolate CE nodes for maintenance. Here’s how to implement this in practice. Isolation via F5 Distributed Cloud Console To isolate a CE node from receiving traffic, in your BGP peer object, edit the Peer and: Change the Outbound BGP routing policy from the one that is allowing the VIP prefixes to the one that is denying the VIP prefixes The CE will stop advertising its VIP routes, and within seconds (based on BGP timers), the upstream firewall will remove this CE from its ECMP paths. Verification During Maintenance On your firewall, verify the route withdrawal (in this case we are using a Fortigate firewall): get router info bgp summary VRF 0 BGP router identifier 10.154.4.119, local AS number 65001 BGP table version is 4 1 BGP AS-PATH entries 0 BGP community entries Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.154.4.33 4 65002 2070 2345 0 0 0 00:04:05 0 10.154.4.160 4 65002 2057 2326 0 0 0 00:12:46 1 Total number of neighbors 2 We are not receiving any prefixes anymore for the 10.154.4.33 peer. get router info routing-table bgp Routing table for VRF=0 B 192.168.100.10/32 [20/255] via 10.154.4.160 (recursive is directly connected, port2), 00:06:34, [1/0] End we have now only one path. Restoring the CE in the data path After maintenance is complete: Return to the BGP Peer configuration in the F5XC Console Restore the original export policy (permit VIP prefixes) Save the configuration On the upstream firewall, confirm that CE prefixes are received again and that ECMP paths are restored Conclusion This article has provided the complete implementation details for deploying BGP and ECMP with F5 Distributed Cloud Customer Edge nodes. You now have: A clear understanding of the architecture at both high and low levels Step-by-step instructions for configuring BGP in F5 Distributed Cloud Console Ready-to-use configurations for both Fortinet FortiGate and Palo Alto Networks firewalls Practical guidance for implementing graceful CE isolation for maintenance By combining the concepts from the first article with the practical configurations in this article, you can build a robust, highly available application delivery infrastructure that maximizes resource utilization, provides automatic failover, and enables zero-downtime maintenance operations. The BGP-based approach transforms your Customer Edge deployment from a traditional Active/Standby model into a full active topology where every node contributes to handling traffic, and any node can be gracefully removed for maintenance without impacting your users.Simplifying and Securing Network Segmentation with F5 Distributed Cloud and Nutanix Flow
Introduction Enterprises often separate environments—such as development and production—to improve efficiency, reduce risk, and maintain compliance. A critical enabler of this separation is network segmentation, which isolates networks into smaller, secured segments—strengthening security, optimizing performance, and supporting regulatory standards. In this article, we explore the integration between Nutanix Flow and F5 Distributed Cloud, showcasing how F5 and Nutanix collaborate to simplify and secure network segmentation across diverse environments—on-premises, remote, and hybrid multicloud. Integration Overview At the heart of this integration is the capability to deploy a F5 Distributed Cloud Customer Edge (CE) inside a Nutanix Flow VPC, establish BGP peering with the Nutanix Flow BGP Gateway, and inject CE-advertised BGP routes into the VPC routing table. This architecture provides full control over application delivery and security within the VPC. It enables selective advertisement of HTTP load balancers (LBs) or VIPs to designated VPCs, ensuring secure and efficient connectivity. By leveraging F5 Distributed Cloud to segment and extend networks to remote location—whether on-premises or in the public cloud—combined with Nutanix Flow for microsegmentation within VPCs, enterprises achieve comprehensive end-to-end security. This approach enforces a consistent security posture while reducing complexity across diverse infrastructures. In our previous article (click here) , we explored application delivery and security. Here, we focus on network segmentation and how this integration simplifies connectivity across environments. Demo Walkthrough The demo consists of two parts: Extending a local network segment from a Nutanix Flow VPC to a remote site using F5 Distributed Cloud. Applying microsegmentation within the network segment using Nutanix Flow Security Next-Gen. San Jose (SJ) serves as our local site, and the demo environment dev3 is a Nutanix Flow VPC with an F5 Distributed Cloud Customer Edge (CE) deployed inside: *Note: The SJ CE is named jy-nutanix-overlay-dev3 in the F5 Distributed Cloud Console and xc-ce-dev3 in the Nutanix Prism Central. On the F5 Distributed Cloud Console, we created a network segment named jy-nutanix-sjc-nyc-segment and we assigned it specifically to the subnet 192.170.84.0/24: eBGP peering is ESTABLISHED between the CE and the Nutanix Flow BGP Gateway in this segment: At the remote site in NYC, a CE named jy-nutanix-nyc is deployed with a local subnet of 192.168.60.0/24: To extend jy-nutanix-sjc-nyc-segment from SJ to NYC, simply assign the segment jy-nutanix-sjc-nyc-segment to the NYC CE local subnet 192.168.60.0/24 in the F5 Distributed Cloud Console: Effortlessly and in no time, the segment jy-nutanix-sjc-nyc-segment is now extended across environments from SJ to NYC: Checking the CE routing table, we can see that the local routes originated from the CEs are being exchanged among them: At the local site SJ, the SJ CE jy-nutanix-overlay-dev3 advertises the remote route originating from the NYC CE jy-nutanix-nyc to the Nutanix Flow BGP Gateway via BGP, and installs the route in the dev3 routing table: SJ VMs can now reach NYC VMs and vice versa, while continuing to use their Nutanix Flow VPC logical router as the default gateway: To enforce granular security within the segment, Nutanix Flow Security Next-Gen provides microsegmentation. Together, F5 Distributed Cloud and Nutanix Flow Security Next-Gen deliver a cohesive solution: F5 Distributed cloud seamlessly extends network segments across environments, while Nutanix Flow Security Next-Gen ensures fine-grained security controls within those segments: Our demo extends a network segment between two data centers, but the same approach can also be applied between on-premises and public cloud environments—delivering flexibility across hybrid multicloud environments. Conclusion F5 Distributed Cloud simplifies network segmentation across hybrid and multi-cloud environments, making it both secure and effortless. By seamlessly extending network segments across any environment, F5 removes the complexity traditionally associated with connecting diverse infrastructures. Combined with Nutanix Flow Security Next-Gen for microsegmentation within each segment, this integration delivers end-to-end protection and consistent policy enforcement. Together, F5 and Nutanix help enterprises reduce operational overhead, maintain compliance, and strengthen security—while enabling agility and scalability across all environments. This integration is coming soon in CY2026. If you’re interested in early access, please contact your F5 representative. Related URLs Delivering Secure Application Services Anywhere with Nutanix Flow and F5 Distributed Cloud | DevCentral F5 Distributed Cloud - https://www.f5.com/products/distributed-cloud-services Nutanix Flow Network Security - https://www.nutanix.com/products/flow
F5 Distributed Cloud Customer Edge Sites: Deploy rapidly and easily to most platforms and providers
Businesses need secure, reliable, and scalable infrastructure to manage their network edge effectively. Secure Mesh Site v2 (SMSv2) on F5 Distributed Cloud brings a robust, next-generation approach to deploying Customer Edge (CE) devices, enabling organizations to streamline operations, boost resilience, and ensure secure communications across distributed environments. Using SMSv2 to deploy CE’s at edge locations in hybrid and multicloud environments significantly reduces the number of clicks and the time it takes to get new sites online. Distributed Cloud supports the following on-prem hypervisors, virtualized platforms, and public cloud providers for rapidly deploying CE images: VMWare, AWS, Azure, GCP, OCI, Nutanix, OpenStack, Equinix, Baremetal, KVM, and OpenShift Virtualization To use SMSv2 you’ll need to have the Distributed Cloud service and an account. In the Distributed Cloud Console, navigate to the Multi-Cloud Network Connect workspace, then go to Site Management > Secure Mesh Sites v2. Now Add Secure Mesh Site, give the site a name and choose your provider. All remaining options can be used as-is with the default values, and can be changed as needed to meet your organization’s networking and business requirements. Demo The following video overview shows how to use Distributed Cloud to deploy CE's on VMware, RedHat OpenShift Virtualization, and Nutanix, using the new SMSv2 capability. Comprehensive Resources and Guides For a deeper dive, comprehensive guides and materials are available at F5 DevCentral. These resources provide step-by-step instructions and best practices for deploying and managing app delivery and security in hybrid environments. The following guides provide step-by-step details for using SMSv2 to deploy CE’s. VMware Setup Example #1:https://github.com/f5devcentral/f5-xc-terraform-examples/tree/main/workflow-guides/smcn/application-dmz#12-create-secure-mesh-site-in-distributed-cloud-services Setup Example #2: https://github.com/f5devcentral/f5-xc-terraform-examples/blob/main/workflow-guides/application-delivery-security/workload/workload-deployments-on-vmware.rst Nutanix https://github.com/f5devcentral/f5-xc-terraform-examples/blob/main/workflow-guides/smsv2-ce/Secure_Mesh_Site_v2_in_Nutanix/secure_mesh_site_v2_in_nutanix.rst OpenShift Virtualization https://github.com/f5devcentral/f5-xc-terraform-examples/blob/main/workflow-guides/application-delivery-security/workload/workload-deployments-on-ocp.rst Azure https://github.com/f5devcentral/f5-xc-terraform-examples/blob/main/workflow-guides/application-delivery-security/workload/workload-deployments-on-azure.rst Looking at the larger picture, using Distributed Cloud to expand or migrate apps across platforms has never been easier. The following technical articles illustrate how Distributed Cloud can leverage multiple platforms and providers to expand and migrate applications hosted in many locations and on a mix of platforms. Distributed Cloud for App Delivery & Security for Hybrid Environments App Migration across Heterogeneous Environments using F5 Distributed Cloud Conclusion By leveraging SMSv2, businesses can enjoy enhanced network scalability, minimized downtime through intelligent failover, and advanced security protocols designed to protect critical data in transit. Whether deploying in multi-cloud, hybrid, or edge-driven architectures, SMSv2 delivers the adaptability, performance, and security necessary to meet the demands of today’s digital-first enterprises.
