Create "Health Monitor" rule for Existing Local Traffic Policy

You could try adding a rule specifically for the port 8686 traffic before default_deny_rule and set the action to Ignore. That should allow the connection to continue on to layer 7 where I'm guessing your iRule is sending the external monitor response on the HTTP_REQUEST event. Something like: If TCP port is 8686 at client accepted time, ignore. Since you've masked the ports for the other rules, it is hard for me to tell whether or not one of those rules would catch the port 8686 traffic first.

Thanks for your response. None of the redacted rules will catch 8686.

Port 8686 is the port that the external monitor uses to monitor the VS. So, the monitor connects, on 8686, performs a GET and I need a Policy which will return a string, with 200 OK.

Also, creating an HTTP_REQUEST rule is not an option. I do see HTTP_METHOD and since the monitor is sending a GET this could work if with "at request time". In the action, or , "Do the following when the traffic is matched" section. I need to understand the syntax I am to configure to return a string with 200 OK.

I want a policy to perform this function. If it is not possible, creating a [policy] rule 8686 and setting ignore makes sense in conjunction with placing an iRule, for the health monitor, on the VS.

I read that a tcl: variable could be set in order to use iRule functionality in the Local traffic Policy as well.

I hope my goals are more clear to you now.

#policy #ltm #rule #HTTP_REQUEST

Thank you for the additional information, Racquel. It does help. Unfortunately, as far as I can tell, there is no way to send a custom HTTP response from a local traffic policy. The functionality does not exist in v15.1 and earlier. I haven't checked in v16.0 yet, but will, just in case. So it would seem an iRule is your only option for sending the custom response string the external monitor application needs from the BIG-IP system, rather than from the application server itself.

Your iRule might look like this:

when HTTP_REQUEST {
    if { [TCP::local_port] == 8686 } {
        HTTP::respond 200 content "<response-string>"
    }
}

I don't think it's necessary to check the HTTP method if no other requests occur to port 8686.

I'll let you know if I find a local traffic policy solution in v16.0.

Thank you so much for checking. This helps.