HTTP URL length limit for LTM

Hi Dhananjay,

 

 

I don't think LTM enforces any limit on the length of a URI. This page (WWW FAQs: What is the maximum length of a URL? Click here) summarises common browser URL limits.

 

 

When you say the load balancer breaks the connection, do you mean LTM sends TCP resets to the client and/or server? Do you see any errors in /var/log/ltm? Else, what are the symptoms of the issue? Do you see the request received by LTM and not sent to the server? Does the server receive the request but log an error? Also, which LTM version are you running?

 

 

Thanks,

 

Aaron

Hi Aaron,

 

Thanks a lot for your response. I almost anticipated response from you.

 

 

You are right that LTM sends TCP reset to apache when apache tries to send 302 (big url). I added irule to print any 302 that LTM receives, and LTM does not print this 302, while I could see other 302s printed. That kind of made us believe that LTM is imposing limit, and hence breaking the connection.

 

 

I dont have access to /var/log/tm. I could only access UI of the load balancer, so is there way to get nay information from UI?

 

 

Regards,

 

Dhananjay.

Sure, you can access the logs under System | Logs | Local Traffic.

 

 

Are you able to capture a tcpdump on LTM while reproducing the issue? That should show conclusively what is happening. If you need help capturing or analysing the trace, you can open a case with F5 Support.

 

 

Aaron

I could capture tcpdump on apache but not on LTM.

 

 

I will pursue this with support to see if we can capture tcpdump on LTM to get better idea.

 

 

Regards,

 

Dhananjay.

You can also capture a tcpdump through the GUI under System | Support.

 

 

Aaron