What is the best way to troubleshoot 500 internal server errors from BIG-IP or client?

Can you plz explain your issue bit more. How you are accessing from big-ip to get error 500?

Can you please post your virtual server configurations?

Use Irule to log http status, you could reference this link https://devcentral.f5.com/s/feed/0D51T00006i7PEcSAM

 

500 errors are generated from the back end servers, F5 doesn't generate these. I would use tcpdump on the internal connection to verify what is being sent to the servers. Verify this with the application team as it may be an invalid request.

I am using a single virtual server with a very vanilla LTM policy with no modifications to lan or wan optimized TCP profiles, no changes to HTTP profile, oneconnect profile used and a access policy for certificate based authentication and SSO using KCD. There is one application with the name of https://app.com with multiple URI's (https://app.com/uri1 https://app.com/uri2 and so on. I am able to authenticate successfully and access all other URI's within this application though for a single URI I am receiving the 500 internal server error.

When accessing the same site by going directly to the webserver, I am able to access the URI that I was previously unable to access due to the 500 internal server error. I do not have access to the virtual server config at this point in time so I am unable to provide the config.

I was curious from the community what is the best way or most common way to identify what is causing this (e.g. fiddler, httpwatch, tcpdump, app server logs, etc.)

tcpdump on load balancer will be the best choice

tcpdump -ni 0.0:nnnp host -vvv -s0 -w /var/tmp/capture.pcap

The application owner reviewed his logs and this particular site was logging unknown host when users attempted to access it through the BIG-IP. DNS records were created for the floating IP and the 500 error has not returned.