Hey DeepSeek, can you write iRules?
Back in time... Two years ago I asked ChatGPT whether it could write iRules. My conclusion after giving several tasks to ChatGPT was, that it can help with simple tasks but it cannot write intermediate or complex iRules. A new AI enters the competition Two weeks ago DeepSeek entered the scene and thought it's a good idea to ask it about its capabilities to write iRules. Spoiler alert: It cannot. New AI, same challenges I asked DeepSeek the same questions I asked ChatGPT 2 years ago. Write me an iRule that redirects HTTP to HTTPS Can you write an iRule that rewrites the host header in HTTP Request and Response? Can you write an iRule that will make a loadbalancing decision based on the HTTP Host header? Can you write an iRule that will make a loadbalancing decision based on the HTTP URI header? Write me an iRule that shows different ASM blocking pages based on the host header. The response should include the support ID. I stopped DeepSeek asking after the 5th question, DeepSeek is clueless about iRules. The answer I got from DeepSeek to 1, 2, 4 and 5 was always the same: when HTTP_REQUEST { # Check if the request is coming to port 80 (HTTP) if { [TCP::local_port] equals 80 } { # Construct the HTTPS URL set host [HTTP::host] set uri [HTTP::uri] set redirect_url "https://${host}${uri}" # Perform the redirect HTTP::redirect $redirect_url } } While this is a solution to task 1, it is plain wrong for 2, 3, 4 and 5. And even for the first challenge this is not a good. Actually it hurts me reading this iRule... Here for example task 2, just wrong... For task 3 DeepSeeks answer was: ChatGPT in 2025 For completeness, I gave the same tasks from 2023 to ChatGPT again. Briefly said - ChatGPT was OK in solving tasks 1-4 in 2023 and still is. It improved it's solution for task 5, the ASM iRule challenge. In 2023 I had two more tasks related to rewriting and redirecting. ChatGPT still failed to provide a solid solution for those two tasks. Conclusion DeepSeek cannot write iRules and ChatGPT still isn't good at it. Write your own iRules or ask the friendly people here on devcentral to help you.
APM Configuration to Support Duo MFA using iRule
Overview BIG-IP APM has supported Duo as an MFA provider for a long time with RADIUS-based integration. Recently, Duo has added support for Universal Prompt that uses Open ID Connect (OIDC) protocol to provide two-factor authentication. To integrate APM as an OIDC client and resource server, and Duo as an Identity Provider (IdP), Duo requires the user’s logon name and custom parameters to be sent for Authentication and Token request. This guide describes the configuration required on APM to enable Duo MFA integration using an iRule. iRules addresses the custom parameter challenges by generating the needed custom values and saving them in session variables, which the OAuth Client agent then uses to perform MFA with Duo. This integration procedure is supported on BIG-IP versions 13.1, 14.1x, 15.1x, and 16.x. To integrate Duo MFA with APM, complete the following tasks: 1. Choose deployment type: Per-request or Per-session 2. Configure credentials and policies for MFA on the DUO web portal 3. Create OAuth objects on the BIG-IP system 4. Configure the iRule 5. Create the appropriate access policy/policies on the BIG-IP system 6. Apply policy/policies and iRule to the APM virtual server Choose deployment type APM supports two different types of policies for performing authentication functions. Per-session policies: Per-session policies provide authentication and authorization functions that occur only at the beginning of a user’s session. These policies are compatible with most APM use cases such as VPN, Webtop portal, Remote Desktop, federation IdP, etc. Per-request policies: Per-request policies provide dynamic authentication and authorization functionality that may occur at any time during a user’s session, such as step-up authentication or auditing functions only for certain resources. These policies are only compatible with Identity Aware Proxy and Web Access Management use cases and cannot be used with VPN or webtop portals. This guide contains information about setting up both policy types. Prerequisites Ensure the BIG-IP system has DNS and internet connectivity to contact Duo directly for validating the user's OAuth tokens. Configure credentials and policies for MFA on Duo web portal Before you can protect your F5 BIG-IP APM Web application with Duo, you will first need to sign up for a Duo account. 1. Log in to the Duo Admin Panel and navigate to Applications. 2. Click Protect an application. Figure 1: Duo Admin Panel – Protect an Application 3. Locate the entry for F5 BIG-IP APM Web in the applications list and click Protect to get the Client ID, Client secret, and API hostname. You will need this information to configure objects on APM. Figure 2: Duo Admin Panel – F5 BIG-IP APM Web 4. As DUO is used as a secondary authentication factor, the user’s logon name is sent along with the authentication request. Depending on your security policy, you may want to pre-provision users in Duo, or you may allow them to self-provision to set their preferred authentication type when they first log on. To add users to the Duo system, navigate to the Dashboard page and click the Add New... -> Add User button. A Duo username should match the user's primary authentication username. Refer to the https://duo.com/docs/enrolling-users link for the different methods of user enrollment. Refer to Duo Universal Prompt for additional information on Duo’s two-factor authentication. Create OAuth objects on the BIG-IP system Create a JSON web key When APM is configured to act as an OAuth client or resource server, it uses JSON web keys (JWKs) to validate the JSON web tokens it receives from Duo. To create a JSON web key: 1. On the Main tab, select Access > Federation > JSON Web Token > Key Configuration. The Key Configuration screen opens. 2. To add a new key configuration, click Create. 3. In the ID and Shared Secret fields, enter the Client ID and Client Secret values respectively obtained from Duo when protecting the application. 4. In the Type list, select the cryptographic algorithm used to sign the JSON web key. Figure 3: Key Configuration screen 5. Click Save. Create a JSON web token As an OAuth client or resource server, APM validates the JSON web tokens (JWT) it receives from Duo. To create a JSON web token: 1. On the Main tab, select Access > Federation > JSON Web Token > Token Configuration. The Token Configuration screen opens. 2. To add a new token configuration, click Create. 3. In the Issuer field, enter the API hostname value obtained from Duo when protecting the application. 4. In the Signing Algorithms area, select from the Available list and populate the Allowed and Blocked lists. 5. In the Keys (JWK) area, select the previously configured JSON web key in the allowed list of keys. Figure 4: Token Configuration screen 6. Click Save. Configure Duo as an OAuth provider APM uses the OAuth provider settings to get URIs on the external OAuth authorization server for JWT web tokens. To configure an OAuth provider: 1. On the Main tab, select Access > Federation > OAuth Client / Resource Server > Provider. The Provider screen opens. 2. To add a provider, click Create. 3. In the Name field, type a name for the provider. 4. From the Type list, select Custom. 5. For Token Configuration (JWT), select a configuration from the list. 6. In the Authentication URI field, type the URI on the provider where APM should redirect the user for authentication. The hostname is the same as the API hostname in the Duo application. 7. In the Token URI field, type the URI on the provider where APM can get a token. The hostname is the same as the API hostname in the Duo application. Figure 5: OAuth Provider screen 8. Click Finished. Configure Duo server for APM The OAuth Server settings specify the OAuth provider and role that Access Policy Manager (APM) plays with that provider. It also sets the Client ID, Client Secret, and Client’s SSL certificates that APM uses to communicate with the provider. To configure a Duo server: 1. On the Main tab, select Access > Federation > OAuth Client / Resource Server > OAuth Server. The OAuth Server screen opens. 2. To add a server, click Create. 3. In the Name field, type a name for the Duo server. 4. From the Mode list, select how you want the APM to be configured. 5. From the Type list, select Custom. 6. From the OAuth Provider list, select the Duo provider. 7. From the DNS Resolver list, select a DNS resolver (or click the plus (+) icon, create a DNS resolver, and then select it). 8. In the Token Validation Interval field, type a number. In a per-request policy subroutine configured to validate the token, the subroutine repeats at this interval or the expiry time of the access token, whichever is shorter. 9. In the Client Settings area, paste the Client ID and Client secret you obtained from Duo when protecting the application. 10. From the Client's ServerSSL Profile Name, select a server SSL profile. Figure 6: OAuth Server screen 11. Click Finished. Configure an auth-redirect-request and a token-request Requests specify the HTTP method, parameters, and headers to use for the specific type of request. An auth-redirect-request tells Duo where to redirect the end-user, and a token-request accesses the authorization server for obtaining an access token. To configure an auth-redirect-request: 1. On the Main tab, select Access > Federation > OAuth Client / Resource Server > Request. The Request screen opens. 2. To add a request, click Create. 3. In the Name field, type a name for the request. 4. For the HTTP Method, select GET. 5. For the Type, select auth-redirect-request. 6. As shown in Figure 7, specify the list of GET parameters to be sent: request parameter with value depending on the type of policy For per-request policy: %{subsession.custom.jwt_duo} For per-session policy: %{session.custom.jwt_duo} client_id parameter with type client-id response_type parameter with type response-type Figure 7: Request screen with auth-redirect-request (Use “subsession.custom…” for Per-request or “session.custom…” for Per-session) 7. Click Finished. To configure a token-request: 1. On the Main tab, select Access > Federation > OAuth Client / Resource Server > Request. The Request screen opens. 2. To add a request, click Create. 3. In the Name field, type a name for the request. 4. For the HTTP Method, select POST. 5. For the Type, select token-request. 6. As shown in Figure 8, specify the list of POST parameters to be sent: client_assertion parameter with value depending on the type of policy For per-request policy: %{subsession.custom.jwt_duo_token} For per-session policy: %{session.custom.jwt_duo_token} client_assertion_type parameter with value urn:ietf:params:oauth:client-assertion-type:jwt-bearer grant_type parameter with type grant-type redirect_uri parameter with type redirect-uri Figure 8: Request screen with token-request (Use “subsession.custom…” for Per-request or “session.custom…” for Per-session) 7. Click Finished. Configure the iRule iRules gives you the ability to customize and manage your network traffic. Configure an iRule that creates the required sub-session variables and usernames for Duo integration. Note: This iRule has sections for both per-request and per-session policies and can be used for either type of deployment. To configure an iRule: 1. On the Main tab, click Local Traffic > iRules. 2. To create an iRules, click Create. 3. In the Name field, type a name for the iRule. 4. Copy the sample code given below and paste it in the Definition field. Replace the following variables with values specific to the Duo application: <Duo Client ID> in the getClientId function with Duo Application ID. <Duo API Hostname> in the createJwtToken function with API Hostname. For example, https://api-duohostname.com/oauth/v1/token. <JSON Web Key> in the getJwkName function with the configured JSON web key. Note: The iRule ID here is set as JWT_CREATE. You can rename the ID as desired. You specify this ID in the iRule Event agent in Visual Policy Editor. Note: The variables used in the below example are global, which may affect your performance. Refer to the K95240202: Understanding iRule variable scope article for further information on global variables, and determine if you use a local variable for your implementation. when ACCESS_POLICY_AGENT_EVENT { if { [ACCESS::policy agent_id] eq "JWT_CREATE" } { set duo_uname [ACCESS::session data get "session.logon.last.username"] # Inline logic for creating JWT set header "{\"alg\":\"HS512\",\"typ\":\"JWT\"}" set exp [expr {[clock seconds] + 900}] set client_id "<Duo Client ID>" set redirect_uri "https://[ACCESS::session data get session.server.network.name]/oauth/client/redirect" set payload "{\"response_type\": \"code\",\"scope\":\"openid\",\"exp\":${exp},\"client_id\":\"${client_id}\",\"redirect_uri\":\"${redirect_uri}\",\"duo_uname\":\"${duo_uname}\"}" set jwt_duo [ACCESS::oauth sign -header $header -payload $payload -alg HS512 -key "<JSON Web Key>"] ACCESS::session data set session.custom.jwt_duo $jwt_duo # JWT Token creation set aud "<Duo API Hostname>" set jti [string range [clock seconds] 0 31] set token_payload "{\"sub\": \"${client_id}\",\"iss\":\"${client_id}\",\"aud\":\"${aud}\",\"exp\":${exp},\"jti\":\"${jti}\"}" set jwt_duo_token [ACCESS::oauth sign -header $header -payload $token_payload -alg HS512 -key "<JSON Web Key>"] ACCESS::session data set session.custom.jwt_duo_token $jwt_duo_token } } when ACCESS_PER_REQUEST_AGENT_EVENT { if { [ACCESS::perflow get perflow.irule_agent_id] eq "JWT_CREATE" } { set duo_uname [ACCESS::session data get "session.logon.last.username"] set header "{\"alg\":\"HS512\",\"typ\":\"JWT\"}" set exp [expr {[clock seconds] + 900}] set client_id "<Duo Client ID>" set redirect_uri "https://[ACCESS::session data get session.server.network.name]/oauth/client/redirect" set payload "{\"response_type\": \"code\",\"scope\":\"openid\",\"exp\":${exp},\"client_id\":\"${client_id}\",\"redirect_uri\":\"${redirect_uri}\",\"duo_uname\":\"${duo_uname}\"}" set jwt_duo [ACCESS::oauth sign -header $header -payload $payload -alg HS512 -key "<JSON Web Key>"] ACCESS::perflow set perflow.custom $jwt_duo # JWT Token creation set aud "<Duo API Hostname>" set jti [string range [clock seconds] 0 31] set token_payload "{\"sub\": \"${client_id}\",\"iss\":\"${client_id}\",\"aud\":\"${aud}\",\"exp\":${exp},\"jti\":\"${jti}\"}" set jwt_duo_token [ACCESS::oauth sign -header $header -payload $token_payload -alg HS512 -key "<JSON Web Key>"] ACCESS::perflow set perflow.scratchpad $jwt_duo_token } } Note: iRule updated 11/27/2024 to eliminate CMP demotion. Figure 9: iRule screen 5. Click Finished. Create the appropriate access policy/policies on the BIG-IP system Per-request policy Skip this section for a per-session type deployment The per-request policy is used to perform secondary authentication with Duo. Configure the access policies through the access menu, using the Visual Policy Editor. The per-request access policy must have a subroutine with an iRule Event, Variable Assign, and an OAuth Client agent that requests authorization and tokens from an OAuth server. You may use other per-request policy items such as URL branching or Client Type to call Duo only for certain target URIs. Figure 10 shows a subroutine named duosubroutine in the per-request policy that handles Duo MFA authentication. Figure 10: Per-request policy in Visual Policy Editor Configuring the iRule Event agent The iRule Event agent specifies the iRule ID to be executed for Duo integration. In the ID field, type the iRule ID as configured in the iRule. Figure 11: iRule Event agent in Visual Policy Editor Configuring the Variable Assign agent The Variable Assign agent specifies the variables for token and redirect requests and assigns a value for Duo MFA in a subroutine. This is required only for per-request type deployment. Add sub-session variables as custom variables and assign their custom Tcl expressions as shown in Figure 12. subsession.custom.jwt_duo_token = return [mcget {perflow.scratchpad}] subsession.custom.jwt_duo = return [mcget {perflow.custom}] Figure 12: Variable Assign agent in Visual Policy Editor Configuring the OAuth Client agent An OAuth Client agent requests authorization and tokens from the Duo server. Specify OAuth parameters as shown in Figure 13. In the Server list, select the Duo server to which the OAuth client directs requests. In the Authentication Redirect Request list, select the auth-redirect-request configured earlier. In the Token Request list, select the token-request configured earlier. Some deployments may not need the additional information provided by OpenID Connect. You could, in that case, disable it. Figure 13: OAuth Client agent in Visual Policy Editor Per-session policy Configure the Per Session policy as appropriate for your chosen deployment type. Per-request: The per-session policy must contain at least one logon page to set the username variable in the user’s session. Preferably it should also perform some type of primary authentication. This validated username is used later in the per-request policy. Per-session: The per-session policy is used for all authentication. A per-request policy is not used. Figures 14a and 14b show a per-session policy that runs when a client initiates a session. Depending on the actions you include in the access policy, it can authenticate the user and perform actions that populate session variables with data for use throughout the session. Figure 14a: Per-session policy in Visual Policy Editor performs both primary authentication and Duo authentication (for per-session use case) Figure 14b: Per-session policy in Visual Policy Editor performs primary authentication only (for per-request use case) Apply policy/policies and iRule to the APM virtual server Finally, apply the per-request policy, per-session policy, and iRule to the APM virtual server. You assign iRules as a resource to the virtual server that users connect. Configure the virtual server’s default pool to the protected local web resource. Apply policy/policies to the virtual server Per-request policy To attach policies to the virtual server: 1. On the Main tab, click Local Traffic > Virtual Servers. 2. Select the Virtual Server. 3. In the Access Policy section, select the policy you created. 4. Click Finished. Figure 15: Access Policy section in Virtual Server (per-request policy) Per-session policy Figure 16 shows the Access Policy section in Virtual Server when the per-session policy is deployed. Figure 16: Access Policy section in Virtual Server (per-session policy) Apply iRule to the virtual server To attach the iRule to the virtual server: 1. On the Main tab, click Local Traffic > Virtual Servers. 2. Select the Virtual Server. 3. Select the Resources tab. 4. Click Manage in the iRules section. 5. Select an iRule from the Available list and add it to the Enabled list. 6. Click Finished.
iRule to count how often the node is down
Hello, I want to monitor the nodes in the pool and, if a node/service goes down three times within five minutes, automatically take it offline and send an email notification. Could you help me determine how to track the number of times a node/service goes down within that five-minute window? Thank you!
Trigger js challenge/Captcha for ip reputation/ip intelligence categories
Problem solved by this Code Snippet Because some ISP or cloud providers do not monitor their users a lot of times client ip addresses are marked as "spam sources" or "windows exploits" and as the ip addresses are dynamic and after time a legitimate user can use this ip addresses the categories are often stopped in the IP intelligence profile or under the ASM/AWAF policy. To still make use of this categories the users coming from those ip addresses can be forced to solve captcha checks or at least to be checked for javascript support! How to use this Code Snippet Have AWAF/ASM and ip intelligence licensed Add AWAF/ASM policy with irule support option (by default not enabled under the policy) or/and Bot profile under the Virtual server Optionally add IP intelligence profile or enable the Ip intelligence under the WAF policy without the categories that cause a lot of false positives, Add the irule and if needed modify the categories for which it triggers Do not forget to first create the data group, used in the code or delete that part of the code and to uncomment the Bot part of the code, if you plan to do js check and not captcha and maybe comment the captcha part ! Code Snippet Meta Information Version: 17.1.3 Coding Language: TCL Code You can find the code and further documentation in my GitHub repository: reputation-javascript-captcha-challlenge/ at main · Nikoolayy1/reputation-javascript-captcha-challlenge when HTTP_REQUEST { # Take the ip address for ip reputation/intelligence check from the XFF header if it comes from the whitelisted source ip addresses in data group "client_ip_class" if { [HTTP::header exists "X-Forwarded-For"] && [class match [IP::client_addr] equals "/Common/client_ip_class"] } { set trueIP [HTTP::header "X-Forwarded-For"] } else { set trueIP [IP::client_addr] } # Check if IP reputation is triggered and it is containing "Spam Sources" if { ([llength [IP::reputation $trueIP]] != 0) && ([IP::reputation $trueIP] contains "Spam Sources") }{ log local0. "The category is [IP::reputation $trueIP] from [IP::client_addr]" # Set the variable 1 or bulean true as to trigger ASM captcha or bot defense javascript set js_ch 1 } else { set js_ch 0 } # Custom response page just for testing if there is no real backend origin server for testing if {!$js_ch} { HTTP::respond 200 content { <html> <head> <title>Apology Page</title> </head> <body> We are sorry, but the site you are looking for is temporarily out of service<br> If you feel you have reached this page in error, please try again. </body> </html> } } } # when BOTDEFENSE_ACTION { # Trigger bot defense action javascript check for Spam Sources # if {$js_ch && (not ([BOTDEFENSE::reason] starts_with "passed browser challenge")) && ([BOTDEFENSE::action] eq "allow") }{ # BOTDEFENSE::action browser_challenge # } # } when ASM_REQUEST_DONE { # Trigger ASM captcha check only for users comming from Spam sources that have not already passed the captcha check (don't have the captcha cookie) if {$js_ch && [ASM::captcha_status] ne "correct"} { set res [ASM::captcha] if {$res ne "ok"} { log local0. "Cannot send captcha_challenge: \"$res\"" } } } Extra References: BOTDEFENSE::action ASM::captcha ASM::captcha_status
Which runs first iRULE or PolicyLTM(With ASM being applied)
Hello all Its well known by the K16590 that LTMPolicies will run before the irules using the same event, for example HTTP_REQUEST in an irule and "at request time" in LTMPolicy. But regardless the order, if the LTM Policy says to enable ASM policy the BIG-IP would still return and process the irule or the traffic would be sent to ASM policy for process leaving the irule whitout a match/process ? In my understanding the LTM Policy would be read first, after that the irule and then the traffic sent to ASM Policy. But i'm not having my irule redirects occuring. In this case of configuration: when HTTP_REQUEST { if {[HTTP::uri] starts_with "/region1/abc"} { HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri] } elseif {[HTTP::uri] starts_with "/region2/abc"} { HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri] } elseif {[HTTP::uri] starts_with "/region3/abc"} { HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri] } elseif {[HTTP::uri] starts_with "/region4/abc"} { HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri] } else { # do nothing } } ltm policy LTM_POLICY_ASM_MYSITE { controls { asm } requires { http } rules { MYSITE { actions { 0 { asm enable policy /Common/ASM_MYSITEWAFPOLICY } } conditions { 0 { http-host values { www.mysiteexample.com.br mysiteexample.com.br } } } } default { actions { 0 { asm enable policy /Common/ASM_MYSITEWAFPOLICY_MISC } } conditions { 0 { http-uri contains values { miscelaneous } } } ordinal 1 } no_asm { actions { 0 { asm disable } } ordinal 2 } } status published strategy first-match }
remove www from domain
Hello Everyone, Could you please assist for below query how it will be achieved. We have a query where the customer wants to remove the www from the request. for example requested comes to https://www.abc.com and they want to remove www and forward to only abc.com. i would like to know if this is applicable using local traffic policy and irules. if possible kindly share the example irule or local traffic policy example to achieve this. Please note: there are some policies configured with https://www.abc.com/etc and being redirected to https://www.abc.com/xyz . will there be any impact on these redirections rules if we remove the www? if yes then do we need to modify all these policies to abc.com and remove www from the redirection statements.? TIA.How to add missing Content-Length header to an HTTP POST request?
Have tried to send an APM HTTP Auth POST request to external authentication server which requires Content-Length header. Seems to be that APM HTTP Auth does not calculate and add the Content-Length header when sending a custom POST. The POST content is small json data but its size varies. HTTP Auth sends the POST to a layered VS which converts the request to https, so can use iRules there. Tried to use HTTP::collect and then calculate the size from collected HTTP::payload and do HTTP::release. However it gets stuck.. Would be nice to be able to do it at the Layered VS. Alternatively thinking of using an iRule agent event in the VPE to form the json POST data and calculate the size into session variables prior the HTTP Auth box in the VPE and using them in the HTTP Auth custom POST definition. Any advice?
How to add missing Content-Length header to an HTTP POST request?
Have tried to send an APM HTTP Auth POST request to external authentication server which requires Content-Length header. Seems to be that APM HTTP Auth does not calculate and add the Content-Length header when sending a custom POST. The POST content is small json data but its size varies. HTTP Auth sends the POST to a layered VS which converts the request to https, so can use iRules there. Tried to use HTTP::collect and then calculate the size from collected HTTP::payload and do HTTP::release. However it gets stuck.. Would be nice to be able to do it at the Layered VS. Alternatively thinking of using an iRule agent event in the VPE to form the json POST data and calculate the size into session variables prior the HTTP Auth box in the VPE and using them in the HTTP Auth custom POST definition. Any advice?
