Error logs TCL script HTTP:host

Your iRule works without any problem on my lab BIG-IP. I don't see any error messages in the /var/log/ltm file. I'm using 14.1.0.3. You could try removing the comments in the iRule. I've seen comments in the iRule being responsible for error messages.

# curl -v http://10.23.98.218 -H "host: www.example.com"
* Rebuilt URL to: http://10.23.98.218/
*   Trying 10.23.98.218...
* Connected to 10.23.98.218 (10.23.98.218) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.40.0
> Accept: */*
> host: www.example.com
>
* HTTP 1.0, assume close after body
< HTTP/1.0 302 Moved Temporarily
< Location: http://example.com/
< Server: BigIP
* HTTP/1.0 connection set to keep alive!
< Connection: Keep-Alive
< Content-Length: 0
<
* Connection #0 to host 10.23.98.218 left intact
#

Hi F5beginner,

Did you attached more than one iRule to the same Virtual Server and one of the iRule processed earlier did already responded the ongoing HTTP request?

Cheers, Kai

Hi Guys,

@Niels van Sluis, thank you for answer, I have deleted comments, but it does not help.

@Kai Wilke, thanks for answer, for virtual server there is used one irule, but in policies there I have defined another tcl rules: Redirect to location 'tcl:https://[getfield [HTTP::host] : 1][HTTP::uri]' at request time, so I guess, this could be reason of error logs, is there any way to change priority of irule ?

Thank you

Hi F5beginner,

the chances are high that the redirect in your LTM Policy is interfering with the subsequent iRule execution. Keep in mind that the LTM Policies are processed always first and you cant change the priority so that the iRule will be processed before LTM Policies.

As an easy fix you may want to wrap your iRule logic into a catch { } command to supress the TCL error whenenver the iRule is unable to execute the redirect.

when HTTP_REQUEST {
	catch {
		# Check if the host starts with www.
		if {[string tolower [HTTP::host]] starts_with "www."}{
			# Redirect with the www. prefix removed to the same URI
			HTTP::redirect "http://[string range [HTTP::host] 4 end][HTTP::uri]"
		}
	}
} 

A slightly more complex (but cleaner) fix, would be to migrate your tasks so that they would either use LTM Policies or iRule but not both at the same time...

Cheers, Kai

Hello,

I agree with Kai. There's a command to check if a redirection event occurs before iRule execution (introduced in 14.x).

https://clouddocs.f5.com/api/irules/HTTP__has_responded.html

KR,

Dario.