APM-DHCP Access Policy Example and Detailed Instructions
Prepared with Mark Quevedo, F5 Principal Software Engineer May, 2020 Sectional Navigation links Important Version Notes || Installation Guide || What Is Going On Here? || Parameters You Set In Your APM Access Policy || Results of DHCP Request You Use in Access Policy || Compatibility Tips and Troubleshooting Introduction Ordinarily you assign an IP address to the “inside end” of an APM Network Tunnel (full VPN connection) from an address Lease Pool, from a static list, or from an LDAP or RADIUS attribute. However, you may wish to assign an IP address you get from a DHCP server. Perhaps the DHCP server manages all available client addresses. Perhaps it handles dynamic DNS for named client workstations. Or perhaps the DHCP server assigns certain users specific IP addresses (for security filtering). Your DHCP server may even assign client DNS settings as well as IP addresses. APM lacks DHCP address assignment support (though f5's old Firepass VPN had it ). We will use f5 iRules to enable DHCP with APM. We will send data from APM session variables to the DHCP server so it can issue the “right” IP address to each VPN tunnel based on user identity, client info, etc. Important Version Notes Version v4c includes important improvements and bug fixes. If you are using an older version, you should upgrade. Just import the template with “Overwrite existing templates” checked, then “reconfigure” your APM-DHCP Application Service—you can simply click “Finished” without changing any options to update the iRules in place. Installation Guide First install the APM-DHCP iApp template (file DHCP_for_APM.tmpl). Create a new Application Service as shown (choose any name you wish). Use the iApp to manage the APM-DHCP virtual servers you need. (The iApp will also install necessary iRules.) You must define at least one APM-DHCP virtual server to receive and send DHCP packets. Usually an APM-DHCP virtual server needs an IP address on the subnet on which you expect your DHCP server(s) to assign client addresses. You may define additional APM-DHCP virtual servers to request IP addresses on additional subnets from DHCP. However, if your DHCP server(s) support subnet-selection (see session.dhcp.subnet below) then you may only need a single APM-DHCP virtual server and it may use any IP that can talk to your DHCP server(s). It is best to give each APM-DHCP virtual server a unique IP address but you may use an BIG-IP Self IP as per SOL13896 . Ensure your APM and APM-DHCP virtual servers are in the same TMOS Traffic Group (if that is impossible set TMOS db key tmm.sessiondb.match_ha_unit to false). Ensure that your APM-DHCP virtual server(s) and DHCP server(s) or relay(s) are reachable via the same BIG-IP route domain. Specify in your IP addresses any non-zero route-domains you are using (e.g., “192.168.0.20%3”)—this is essential. (It is not mandatory to put your DHCP-related Access Policy Items into a Macro—but doing so makes the below screenshot less wide!) Into your APM Access Policy, following your Logon Page and AD Auth (or XYZ Auth) Items (etc.) but before any (Full/Advanced/simple) Resource Assign Item which assigns the Network Access Resource (VPN), insert both Machine Info and Windows Info Items. (The Windows Info Item will not bother non-Windows clients.) Next insert a Variable Assign Item and name it “DHCP Setup”. In your “DHCP Setup” Item, set any DHCP parameters (explained below) that you need as custom session variables. You must set session.dhcp.servers. You must also set session.dhcp.virtIP to the IP address of an APM-DHCP virtual server (either here or at some point before the “DHCP_Req” iRule Event Item). Finally, insert an iRule Event Item (name it “DHCP Req”) and set its Agent ID to DHCP_req. Give it a Branch Rule “Got IP” using the expression “expr {[mcget {session.dhcp.address}] ne ""}” as illustrated. You must attach iRule ir-apm-policy-dhcp to your APM virtual server (the virtual server to which your clients connect). Neither the Machine Info Item nor the Windows Info Item is mandatory. However, each gathers data which common DHCP servers want to see. By default DHCP_req will send that data, when available, to your DHCP servers. See below for advanced options: DHCP protocol settings, data sent to DHCP server(s), etc. Typically your requests will include a user identifier from session.dhcp.subscriber_ID and client (machine or connection) identifiers from other parameters. The client IP address assigned by DHCP will appear in session.dhcp.address. By default, the DHCP_req iRule Event handler will also copy that IP address into session.requested.clientip where the Network Access Resource will find it. You may override that behavior by setting session.dhcp.copy2var (see below). Any “vendor-specific information” supplied by the DHCP server 1 (keyed by the value of session.dhcp.vendor_class) will appear in variables session.dhcp.vinfo.N where N is a tag number (1-254). You may assign meanings to tag numbers. Any DNS parameters the DHCP server supplies 2 are in session.dhcp.dns_servers and session.dhcp.dns_suffix. If you want clients to use those DNS server(s) and/or DNS default search domain, put the name of every Network Access Resource your Access Policy may assign to the client into the session.dhcp.dns_na_list option. NB: this solution does not renew DHCP address leases automatically, but it does release IP addresses obtained from DHCP after APM access sessions terminate. 3 Please configure your DHCP server(s) for an address lease time longer than your APM Maximum Session Timeout. Do not configure APM-DHCP virtual servers in different BIG-IP route domains so they share any part of a DHCP client IP range (address lease pool). For example, do not use two different APM-DHCP virtual servers 10.1.5.2%6 and 10.1.5.2%8 with one DHCP client IP range 10.1.5.10—10.1.5.250. APM-DHCP won’t recognize when two VPN sessions in different route domains get the same client IP from a non-route-domain-aware DHCP server, so it may not release their IP’s in proper sequence. This solution releases DHCP address leases for terminated APM sessions every once in a while, when a new connection comes in to the APM virtual server (because the BIG IP only executes the relevant iRules on the “event” of each new connection). When traffic is sparse (say, in the middle of the night) there may be some delay in releasing addresses for dead sessions. If ever you think this solution isn’t working properly, be sure to check the BIG IP’s LTM log for warning and error messages. DHCP Setup (a Variable Assign Item) will look like: Put the IP of (one of) your APM-DHCP virtual server(s) in session.dhcp.virtIP. Your DHCP server list may contain addresses of DHCP servers or relays. You may list a directed broadcast address (e.g., “172.16.11.255”) instead of server addresses but that will generate extra network chatter. To log information about DHCP processing for the current APM session you may set variable session.dhcp.debug to true (don’t leave it enabled when not debugging). DHCP Req (an iRule Event Item) will look like: Note DHCP Req branch rules: If DHCP fails, you may wish to warn the user: (It is not mandatory to Deny access after DHCP failure—you may substitute another address into session.requested.clientip or let the Network Access Resource use a Lease Pool.) What is going on here? We may send out DHCP request packets easily enough using iRules’ SIDEBAND functions, but it is difficult to collect DHCP replies using SIDEBAND. 4 Instead, we must set up a distinct LTM virtual server to receive DHCP replies on UDP port 67 at a fixed address. We tell the DHCP server(s) we are a DHCP relay device so replies will come back to us directly (no broadcasting). 5 For a nice explanation of the DHCP request process see http://technet.microsoft.com/en-us/library/cc940466.aspx. At this time, we support only IPv4, though adding IPv6 would require only toil, not genius. By default, a DHCP server will assign a client IP on the subnet where the DHCP relay device (that is, your APM-DHCP virtual server) is homed. For example, if your APM-DHCP virtual server’s address were 172.30.4.2/22 the DHCP server would typically lease out a client IP on subnet 172.30.4.0. Moreover, the DHCP server will communicate directly with the relay-device IP so appropriate routes must exist and firewall rules must permit. If you expect to assign client IP’s to APM tunnel endpoints on multiple subnets you may need multiple APM-DHCP virtual servers (one per subnet). Alternatively, some but not all DHCP servers 6 support the rfc3011 “subnet selection” or rfc3527 “subnet/link-selection sub-option” so you can request a client IP on a specified subnet using a single APM-DHCP virtual server (relay device) IP which is not homed on the target subnet but which can communicate easily with the DHCP server(s): see parameter session.dhcp.subnet below. NOTE: The subnet(s) on which APM Network Access (VPN) tunnels are homed need not exist on any actual VLAN so long as routes to any such subnet(s) lead to your APM (BIG-IP) device. Suppose you wish to support 1000 simultaneous VPN connections and most of your corporate subnets are /24’s—but you don’t want to set up four subnets for VPN users. You could define a virtual subnet—say, 172.30.4.0/22—tell your DHCP server(s) to assign addresses from 172.30.4.3 thru 172.30.7.254 to clients, put an APM-DHCP virtual server on 172.30.4.2, and so long as your Layer-3 network knows that your APM BIG-IP is the gateway to 172.30.4.0/22, you’re golden. When an APM Access Policy wants an IP address from DHCP, it will first set some parameters into APM session variables (especially the IP address(es) of one or more DHCP server(s)) using a Variable Assign Item, then use an iRule Event Item to invoke iRule Agent DHCP_req in ir apm policy dhcp. DHCP_req will send DHCPDISCOVERY packets to the specified DHCP server(s). The DHCP server(s) will reply to those packets via the APM-DHCP virtual-server, to which iRule ir apm dhcp must be attached. That iRule will finish the 4-packet DHCP handshake to lease an IP address. DHCP_req handles timeouts/retransmissions and copies the client IP address assigned by the DHCP server into APM session variables for the Access Policy to use. We use the APM Session-ID as the DHCP transaction-ID XID and also (by default) in the value of chaddr to avert collisions and facilitate log tracing. Parameters You Set In Your APM Access Policy Required Parameters session.dhcp.virtIP IP address of an APM-DHCP virtual-server (on UDP port 67) with iRule ir-apm-dhcp. This IP must be reachable from your DHCP server(s). A DHCP server will usually assign a client IP on the same subnet as this IP, though you may be able to override that by setting session.dhcp.subnet. You may create APM-DHCP virtual servers on different subnets, then set session.dhcp.virtIP in your Access Policy (or branch) to any one of them as a way to request a client IP on a particular subnet. No default. Examples (“Custom Expression” format): expr {"172.16.10.245"} or expr {"192.0.2.7%15"} session.dhcp.servers A TCL list of one or more IP addresses for DHCP servers (or DHCP relays, such as a nearby IP router). When requesting a client IP address, DHCP packets will be sent to every server on this list. NB: IP broadcast addresses like 10.0.7.255 may be specified but it is better to list specific servers (or relays). Default: none. Examples (“Custom Expression” format): expr {[list "10.0.5.20" "10.0.7.20"]} or expr {[list "172.30.1.20%5"]} Optional Parameters (including some DHCP Options) NOTE: when you leave a parameter undefined or empty, a suitable value from the APM session environment may be substituted (see details below). The defaults produce good results in most cases. Unless otherwise noted, set parameters as Text values. To exclude a parameter entirely set its Text value to '' [two ASCII single-quotes] (equivalent to Custom Expression return {''} ). White-space and single-quotes are trimmed from the ends of parameter values, so '' indicates a nil value. It is best to put “Machine Info” and “Windows Info” Items into your Access Policy ahead of your iRule Event “DHCP_req” Item (Windows Info is not available for Mac clients beginning at version 15.1.5 as they are no longer considered safe). session.dhcp.debug Set to 1 or “true” to log DHCP-processing details for the current APM session. Default: false. session.dhcp.firepass Leave this undefined or empty (or set to “false”) to use APM defaults (better in nearly all cases). Set to “true” to activate “Firepass mode” which alters the default values of several other options to make DHCP messages from this Access Policy resemble messages from the old F5 Firepass product. session.dhcp.copy2var Leave this undefined or empty (the default) and the client IP address from DHCP will be copied into the Access Policy session variable session.requested.clientip, thereby setting the Network Access (VPN) tunnel’s inside IP address. To override the default, name another session variable here or set this to (Text) '' to avert copying the IP address to any variable. session.dhcp.dns_na_list To set the client's DNS server(s) and/or DNS default search domain from DHCP, put here a Custom Expression TCL list of the name(s) of the Network Access Resource(s) you may assign to the client session. Default: none. Example: expr {[list "/Common/NA" "/Common/alt-NA"]} session.dhcp.broadcast Set to “true” to set the DHCP broadcast flag (you almost certainly should not use this). session.dhcp.vendor_class Option 60 A short string (32 characters max) identifying your VPN server. Default: “f5 APM”. Based on this value the DHCP server may send data to session.dhcp.vinfo.N (see below). session.dhcp.user_class Option 77 A Custom Expression TCL list of strings by which the DHCP server may recognize the class of the client device (e.g., “kiosk”). Default: none (do not put '' here). Example: expr {[list "mobile" "tablet"]} session.dhcp.client_ID Option 61 A unique identifier for the remote client device. Microsoft Windows DHCP servers expect a representation of the MAC address of the client's primary NIC. If left undefined or empty the primary MAC address discovered by the Access Policy Machine Info Item (if any) will be used. If no value is set and no Machine Info is available then no client_ID will be sent and the DHCP server will distinguish clients by APM-assigned ephemeral addresses (in session.dhcp.hwcode). If you supply a client_ID value you may specify a special code, a MAC address, a binary string, or a text string. Set the special code “NONE” (or '') to avoid sending any client_ID, whether Machine Info is available or not. Set the special code “XIDMAC” to send a unique MAC address for each APM VPN session—that will satisfy DHCP servers desiring client_ID‘s while averting IP collisions due to conflicting Machine Info MAC’s like Apple Mac Pro’s sometimes provide. A value containing twelve hexadecimal digits, possibly separated by hyphens or colons into six groups of two or by periods into three groups of four, will be encoded as a MAC address. Values consisting only of hexadecimal digits, of any length other than twelve hexits, will be encoded as a binary string. A value which contains chars other than [0-9A-Fa-f] and doesn't seem to be a MAC address will be encoded as a text string. You may enclose a text string in ASCII single-quotes (') to avert interpretation as hex/binary (the quotes are not part of the text value). On the wire, MAC-addresses and text-strings will be prefixed by type codes 0x01 and 0x00 respectively; if you specify a binary string (in hex format) you must include any needed codes. Default: client MAC from Machine Info, otherwise none. Example (Text value): “08-00-2b-2e-d8-5e”. session.dhcp.hostname Option 12 A hostname for the client. If left undefined or empty, the short computer name discovered by the APM Access Policy Windows Info Item (if any) will be used. session.dhcp.subscriber_ID Sub-option 6 of Option 82 An identifier for the VPN user. If undefined or empty, the value of APM session variable session.logon.last.username will be used (generally the user's UID or SAMAccountName). session.dhcp.circuit_ID Sub-option 1 of Option 82 An identifier for the “circuit” or network endpoint to which client connected. If left undefined or empty, the IP address of the (current) APM virtual server will be used. session.dhcp.remote_ID Sub-option 2 of Option 82 An identifier for the client's end of the connection. If left undefined or empty, the client’s IP address + port will be used. session.dhcp.subnet Option 118 Sub-option 5 of Option 82 The address (e.g., 172.16.99.0) of the IP subnet on which you desire a client address. With this option you may home session.dhcp.virtIP on another (more convenient) subnet. MS Windows Server 2016 added support for this but some other DHCP servers still lack support. Default: none. session.dhcp.hwcode Controls content of BOOTP htype, hlen, and chaddr fields. If left undefined or empty, a per-session value optimal in most situations will be used (asserting that chaddr, a copy of XID, identifies a “serial line”). If your DHCP server will not accept the default, you may set this to “MAC” and chaddr will be a locally-administered Ethernet MAC (embedding XID). When neither of those work you may force any value you wish by concatenating hexadecimal digits setting the value of htype (2 hexits) and chaddr (a string of 0–32 hexits). E.g., a 6-octet Ethernet address resembles “01400c2925ea88”. Most useful in the last case is the MAC address of session.dhcp.virtIP (i.e., a specific BIG-IP MAC) since broken DHCP servers may send Layer 2 packets directly to that address. Results of DHCP Request For Use In Access Policy session.dhcp.address <-- client IP address assigned by DHCP! session.dhcp.message session.dhcp.server, session.dhcp.relay session.dhcp.expires, session.dhcp.issued session.dhcp.lease, session.dhcp.rebind, session.dhcp.renew session.dhcp.vinfo.N session.dhcp.dns_servers, session.dhcp.dns_suffix session.dhcp.xid, session.dhcp.hex_client_id, session.dhcp.hwx If a DHCP request succeeds the client IP address appears in session.dhcp.address. If that is empty look in session.dhcp.message for an error message. The IP address of the DHCP server which issued (or refused) the client IP is in session.dhcp.server (if session.dhcp.relay differs then DHCP messages were relayed). Lease expiration time is in session.dhcp.expires. Variables session.dhcp.{lease, rebind, renew} indicate the duration of the address lease, plus the rebind and renew times, in seconds relative to the clock value in session.dhcp.issued (issued time). See session.dhcp.vinfo.N where N is tag number for Option 43 vendor-specific information. If the DHCP server sends client DNS server(s) and/or default search domain, those appear in session.dhcp.dns_servers and/or session.dhcp.dns_suffix. To assist in log analysis and debugging, session.dhcp.xid contains the XID code used in the DHCP request. The client_ID value (if any) sent to the DHCP server(s) is in session.dhcp.hex_client_id. The DHCP request’s htype and chaddr values (in hex) are concatenated in session.dhcp.hwx. Compatibility Tips and Troubleshooting Concern Response My custom parameter seems to be ignored. You should set most custom parameters as Text values (they may morph to Custom Expressions). My users with Apple Mac Pro’s sometimes get no DHCP IP or a conflicting one. A few Apple laptops sometimes give the Machine Info Item bogus MAC addresses. Set session.dhcp.client_ID to “XIDMAC“ to use unique per-session identifiers for clients. After a VPN session ends, I expect the very next session to reuse the same DHCP IP but that doesn’t happen. Many DHCP servers cycle through all the client IP’s available for one subnet before reusing any. Also, after a session ends APM-DHCP takes a few minutes to release its DHCP IP. When I test APM-DHCP with APM VE running on VMware Workstation, none of my sessions gets an IP from DHCP. VMware Workstation’s built-in DHCP server sends bogus DHCP packets. Use another DHCP server for testing (Linux dhcpd(8) is cheap and reliable). I use BIG-IP route domains and I notice that some of my VPN clients are getting duplicate DHCP IP addresses. Decorate the IP addresses of your APM-DHCP virtual servers, both in the iApp and in session.dhcp.virtIP, with their route-domain ID’s in “percent notation” like “192.0.2.5%3”. APM-DHCP is not working. Double-check your configuration. Look for errors in the LTM log. Set session.dhcp.debug to “true” before trying to start a VPN session, then examine DHCP debugging messages in the LTM log to see if you can figure out the problem. Even after looking at debugging messages in the log I still don’t know why APM-DHCP is not working. Run “tcpdump –ne -i 0.0 -s0 port 67” to see where the DHCP handshake fails. Are DISCOVER packets sent? Do any DHCP servers reply with OFFER packets? Is a REQUEST sent to accept an OFFER? Does the DHCP server ACK that REQUEST? If you see an OFFER but no REQUEST, check for bogus multicast MAC addresses in the OFFER packet. If no OFFER follows DISCOVER, what does the DHCP server’s log show? Is there a valid zone/lease-pool for you? Check the network path for routing errors, hostile firewall rules, or DHCP relay issues. Endnotes In DHCP Option 43 (rfc2132). In DHCP Options 6 and 15 (rfc2132). Prior to version v3h, under certain circumstances with some DHCP servers, address-release delays could cause two active sessions to get the same IP address. And even more difficult using [listen], for those of you in the back of the room. A bug in some versions of VMware Workstation’s DHCP server makes this solution appear to fail. The broken DHCP server sends messages to DHCP relays in unicast IP packets encapsulated in broadcast MAC frames. Anormal BIG-IP virtual server will not receive such packets. As of Winter 2017 the ISC, Cisco, and MS Windows Server 2016 DHCP servers support the subnet/link selection options but older Windows Server and Infoblox DHCP servers do not. Supporting Files - Download attached ZIP File Here.
Improve BIG-IP APM VPN speed with TLS dynamic record size
After successfully setting up BIG-IP APM network access, and running it for sometime, you may be looking for ways to optimize VPN speed for your users. This article discusses one way you can do that. Feature Description Beginning in BIG-IP 12.1.0, the Client SSL profile includes a feature that enables dynamic record size in TLS. When applied to a F5 BIG-IP Access Policy Manager (APM) network access VPN TLS virtual server, this can improve VPN speeds for your users. It has been found that certain protocols, notably HTTP, show better client response times using this method. For more information on the Allow Dynamic Record Sizing setting down to the packet level, refer to the following resources TheAbout dynamic record sizing section of the BIG-IP System: SSL Administration manual. Boosting TLS Performance with Dynamic Record Sizing on BIG-IP on DevCentral. SSL Profiles Part 11: TLS Optimizationon DevCentral. Important: Dynamic record size is a TLS enhancement and does not apply to BIG-IP APM network access DTLS virtual servers. Do not enable dynamic record size on DTLS. When you want to optimize network performance, you must allocate time to tune each configuration to match the requirements specific to your environment. Additionally, note that configuration changes that improve performance may increase BIG-IP system resource (CPU, memory) usage. Testing dynamic record size on VPN speeds Having discussed the theory behind the feature, we will now perform tests to see how it affects VPN speeds. Network bandwidth can vary depending on many factors, for instance, peak vs non-peak hours. When more users are connected to a VPN, download speeds can decrease significantly. It is therefore important to establish a baseline network bandwidth and download speed at the beginning: Baseline AWS environment Windows Client (Seattle) --VPN --> BIG-IP APM (Oregon) --local LAN-->Apache and iperf servers AWS environment: BIG-IP APM 17.1.0 VE on AWS (F5 BIG-IP VE - ALL modules, m5.xlarge, 1 Gbps, AWS) located in us-west-2 Oregon. Note: Ensure you use at least the recommended size (m5.xlarge) and at least 1Gbps on AWS to make sure there are no bandwidth and resource limits. Windows client in located in Seattle Using iperf3 to measure network bandwidth Using curl to download a 377MB apmclient.iso Optional: You can optionally test using the developer tools on your browser. I used firefox; as the results did not differ significantly from curl. They are not included in this article. Baseline test results These are measured with all default settings on BIG-IP APM and dynamic record sizing not enabled: curl download results Average download speed: 4950k C:\Windows\system32>curl -k -o null https://10.0.128.23/apmclient.iso % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 377M 100 377M 0 0 4950k 0 0:01:18 0:01:18 --:--:-- 4988k iperf3 results Network bandwidth: 4873 KB/sec c:\Users\klau\Desktop\iperf-3.1.3-win64>iperf3.exe -c 10.0.128.24 --get-server-output -i 1 -f K -R Connecting to host 10.0.128.24, port 5201 Reverse mode, remote host 10.0.128.24 is sending [ 4] local 10.0.128.31 port 61284 connected to 10.0.128.24 port 5201 [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 4.33 MBytes 4434 KBytes/sec [ 4] 1.00-2.00 sec 4.67 MBytes 4785 KBytes/sec [ 4] 2.00-3.00 sec 4.86 MBytes 4977 KBytes/sec [ 4] 3.00-4.00 sec 4.77 MBytes 4878 KBytes/sec [ 4] 4.00-5.00 sec 4.72 MBytes 4834 KBytes/sec [ 4] 5.00-6.00 sec 4.78 MBytes 4898 KBytes/sec [ 4] 6.00-7.00 sec 4.87 MBytes 4989 KBytes/sec [ 4] 7.00-8.00 sec 4.81 MBytes 4925 KBytes/sec [ 4] 8.00-9.00 sec 4.71 MBytes 4823 KBytes/sec [ 4] 9.00-10.00 sec 4.82 MBytes 4934 KBytes/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-10.00 sec 48.0 MBytes 4919 KBytes/sec 9 sender [ 4] 0.00-10.00 sec 47.6 MBytes 4873 KBytes/sec receiver Server output: [...] [ 5] 0.00-10.04 sec 48.0 MBytes 4900 KBytes/sec 9 sender Test 1: Enabling dynamic record size from baseline Comparing with baseline results after enabling dynamic record size Baseline: Dynamic record size disabled dynamic record size enabled Percentage improvement curl average download, k 4950 5272 6.51% iperf3 network bandwidth, KBytes/sec 4873 5138 5.44% While this may not appear to be too high on the AWS cloud, there is also received feedback from customers that they see greater improvements in environments, especially in cases where the end-to-end latencies increase. Implementation strategy and recommendations As you plan to introduce this in your environment, take note of the following recommendations: Every environment is unique Many factors can affect network performance. This can range from VLAN settings (For example. MTU), TCP settings, intermediate network device throttling, and so on. You must perform testing in your own environment before enabling the feature. Implement the feature incrementally for a selected group of users. There are different ways to do this. For example, use an iRule to redirect users based on a URL, to a separate virtual server using a different Client SSL profile that has the feature enabled. Refer to SSL::allow_dynamic_record_sizing on Clouddocs. Monitor BIG-IP system logs and resource usage After you enable dynamic record size, make sure that your BIG-IP system continues to function as expected by monitoring the following monitor /var/log/ltm and /var/log/apm log files monitor BIG-IP CPU and memory usage. For example, you can select Dashboard on the Configuration utility, generating a QKview and analyze it in iHealth and so on. For more information, refer to K71764661: Understanding BIG-IP CPU usage and K16419: Overview of BIG-IP memory usage Verify and analyze SSL statistics Use the tmsh command inK41057430: Enhanced SSL profile statistics and check for failures. The SSL Dynamic Record Sizes section should also indicate use of large record sizes. Boosting TLS Performance with Dynamic Record Sizing on BIG-IP Conclusion There are a variety of different ways to improve VPN speeds, and this article describes just one. For other options and considerations, refer to K31143831: VPN for business continuity | Chapter 5: Optimizing Network Access VPN.[Workaound] User required to manually start EPI and VPN in browsers
After upgrading to version 16.1.4 the users need to manually start the End Point Inspector and the Web Initiated VPN by clicking on a "Start" button. This is describe in this KB. I created a user-common.js that will automatically click on the start button for the user. However, please note that this workround works as of 3rd of November 2023, but might stop working in the future in different browsers. In order to activate the workaround you need to have an Access Policy of the Moden type. Then go to Customizations -> Advanced -> Acces Profiles -> <Your Access Profile> -> Common Add the followinf to the file user-common.js define(["require", "exports", "apmui"], function (require, exports, apmui_1) { "use strict"; Object.defineProperty(exports, "__esModule", { value: true }); var app = apmui_1.App.get(); app.subscribe(apmui_1.EventType.EPS_CHECK_PROGRESS, function (_, store) { var btns = document.getElementsByClassName("apmui-button"); if (btns.length == 0) { console.log("Failed to find button..."); return; } btns[0].click(); }); app.subscribe(apmui_1.EventType.DIALOG_OPEN, function (_, store) { setTimeout(function () { var dialog = document.getElementById("sna_auto_start_not_supported"); if (dialog == null) { console.log("Didn't find the right dialog"); return; } var btns = dialog.getElementsByClassName("apmui-button"); if (btns.length == 0) { console.log("Didn't find the start button"); return; } btns[0].click(); }, 100); }); }); If you have a better solution to this, please let me know. This was just what I came up with when asked by customers that the new "Start" button had created confusion among their users.
cant access to management interface after vpn using apm established
i had configured network access vpn using APM module, i tried to split tunneling the network of my management access, but unfortunately when the vpn established i cant connect to my f5 management interface. i tried to add VS with my pool member is my f5 management ip address, where VS ip address is 1 network with my VPN user, the service is https, and the pool member is my f5 management ip address with service port is 443. and then the result is i can ping my VS but i cant connect to my VS which have the pool member is my f5 management ip address with port 443 any idea how can i access to my F5 after vpn using APM established? really appreciate your help thank youDomain was fixed in Internet Security on Internet Explorer (IE)
How it possible to edit the domain in Internet Security when it's prompt as this image below example image I has set the F5 APM to fixed the domain name, using Variable Resource Assign expr { "[mcget {session.ad.last.actualdomain}]\\[mcget {session.logon.last.username}]" } I try with Chrome, Firefox so it's work well, but in IE have fixed the Domain for each PC. For my guess, I think the behavior of Chrome and Firefox will be like Username : username Password : password after we input the information above the Variable Resource Assign will automatically add the domain to be the domain\username . On the other hand, the result of IE (that browser fix domain) will be like RINGWORLD\domain\username that will make authentication abort. My idea is to check the browser type, if the client use IE -> the F5 APM will remove the domain that fixed from the browser. Finally, I am not sure that it's possible to do it like this way or someone can give me a better solution. -F5 APM with Version 12.1.2 HF1 -IE Version 11 -F5 SSL VPN Thank you very muchIntegrate F5 SSL VPN with CheckPoint Identity Awareness
Problem this snippet solves: Goal This snippet allows you to use "identity based" rules on a CheckPoint firewall to manage the permissions for users connected by SSL VPN with F5 APM. Context Usually, when deploying SSL VPN with F5 APM, you need to use F5 ACL to manage the permissions for the VPN users defining which user or group is allowed to reach which servers or networks. These rules may be duplicates of existing rules implemented in the core firewall of the company. Since the mappings (username, assigned VPN IP) is known only by F5, it is impossible for the core firewall to apply the proper filtering based on users identity. The idea with this snippet is to be able to manage all the rules centrally on the CheckPoint firewall such as the following : User "Paul Anderson" is allowed to reach the network 10.10.1.0/24 User "Robert Schmitt" is allowed to go everywhere except 10.10.2.0/24 Active Directory group "Admins" is allowed to go everywhere on TCP ports 443 and 22 This snippet allows this kind of rules defined in a CheckPoint gateway to work also when the users are connected with F5 APM SSL VPN. How it works We are using the new CheckPoint R80 Web API to spread the association (username, assigned VPN IP) to the CheckPoint gateway. Indeed, the VPN connection follows the following steps : The user "Paul Robert" connects the F5 SSL VPN (through the Edge Client or the browser helper) The user "Paul Robert" is given an IP by F5 within the "lease pool" : let's say 192.168.1.13 F5 sends an HTTP request to the CheckPoint Identity Awareness Web API containing the association : 192.168.1.13 --> "Paul Robert" When Paul generates traffic through the VPN, this traffic is seen as coming from the source IP 192.168.1.13 from the CheckPoint firewall point of view. The firewall is able to apply the proper "identity based rules" because it knows that 192.168.1.13 is actually "Paul Robert" How to use this snippet: Requirements APM module provisioned on F5 SSL VPN service already configured with APM Import the iRule "HTTP Super Sideband Requestor" on your F5 Download here This iRule must be named "HSSR" and must be in the partition "Common" CheckPoint Gateway R80 with the blade Identity Awareness enabled Existing firewall rules based on identity CheckPoint Identity Awareness Web API By default, the WebAPI is not enabled in a CheckPoint gateway, you need to first configure it. The configuration is simply setting up which source IP are allowed to use the API and defining a secret for each client. It is done in the gateway object from the Smart Console : Here I configured my F5 as a WebAPI client with the secret "Fr38N....." Once the configuration is done, you need to install the policy on the gateway to apply the configuration. To validate the WebAPI is working, you can use the following bash command on F5 : curl -k -v --data '{ "shared-secret":"<api_secret>", "ip-address":"1.2.3.4", "user":"testuser1" }' https://<checkpoint_gw_ip/_IA_API/v1.0/add-identity This command sends the association (IP : "1.2.3.4" --> User: "testuser1"). If successful, you should get the following message from the gateway : { "ipv4-address" : "1.2.3.4", "message" : "Association sent to PDP." } F5 configuration Once you've validated the CheckPoint WebAPI is working and the F5 SSL VPN is ready, the needed configuration to integrate F5 with CheckPoint is composed of the 4 following steps : Create a new pool Pool member: CheckPoint gateway IP / port 443 Monitoring TCP Create a new local virtual server Type: standard Destination : A fake, non existing IP address (such as 1.1.1.1 for example)* Port : 443 Server SSL profile : serverssl-insecure-compatible Pool : previously created pool Source address translation: Automap (if needed) Import the iRule in this snippet with the following adaptations : Change <secret_api> with your WebAPI secret Change <vs_name> with the name of the previously created virtual server Add this iRule to your existing SSL VPN virtual server Testing After having applied the iRule, every new VPN connection should append the following line in the log file /var/log/ltm on F5 : VPN : Publishing VPN IP in CheckPoint identity - SUCCESS Moreover, all your existing "identity based rules" in CheckPoint must now work with clients connected through the F5 VPN. Notes For this configuration we made two assumptions : The "network access" object for the VPN is not doing any SNAT (SNAT Pool: none). Indeed, if we are using "Automap" for the network access, all the connected clients are hidden behind the same IP, so there is no way to identify the users outside of F5. In the iRule, we suppose the username to send to CheckPoint is present in the APM variable "session.logon.last.username". If it's not your case, you need to adapt the iRule by changing this variable name. Code : when RULE_INIT { ## Secret configured on CheckPoint to authenticate the F5 to the Web API set static::checkpoint_api_secret " " } when CLIENT_ACCEPTED { ACCESS::restrict_irule_events disable } when HTTP_REQUEST { # Thx to John Alam for this way to get assigned VPN IP # https://devcentral.f5.com/s/questions/how-do-i-record-the-ip-assigned-to-a-client-after-login if { [HTTP::uri] starts_with "/myvpn?sess=" } { after 5000 { set api_username [ACCESS::session data get session.logon.last.username] set vpn_ip [ACCESS::session data get session.assigned.clientip] set jsonBody "{ \"shared-secret\":\"$static::checkpoint_api_secret\", \"ip-address\":\"$vpn_ip\", \"user\":\"$api_username\" }" set sts [call /Common/HSSR::http_req -virt /Common/ -uri "http://checkpoint.webapi.local/_IA_API/v1.0/add-identity" -method POST -body $jsonBody -rbody apiResp] if { $apiResp contains "Association sent to PDP" } { log local0. "VPN : Publishing VPN IP in CheckPoint identity - SUCCESS" } else { log local0. "VPN ERROR : Failed to publish the VPN IP in CheckPoint Identity : $apiResp" } } } } Tested this on version: 13.0
session variable not being substituted?
As a second check to VPN access, I need to check the mac address of the machine against a database we have. I've set up an AAA HTTP server with a form-based http get that works when I specify an absolute value. the url I use is http://server.full.name/infoserv/cgi-bin/computing/database/hardware/vpn/MacValid.asp?MacAddress=00:00:00:00:00:00 but when I change it to http://server.full.name/infoserv/cgi-bin/computing/database/hardware/vpn/MacValid.asp?MacAddress=%{session.machine_info.net_adapter.list.[0].mac_address} the session variable is NOT substituted but passed to our web server as "%{session.machine_info.net_adapter.list.[0].mac_address" I've also tried %{session.client.mac_address} with the same result. Is there some trick to getting session variables to work in the "form action" field? thanks
