http response code 205 seems to get "blocked" by LB

[Ashis_K_Patra]

While accessing the URL via Big IP, the response code 205 is getting blocked. 

Please advise how can I fix this? 

[Niels_van_Sluis]

Can you share some more details about the problem? Are there any error messages you can share? What modules are being used (LTM, APM, ASM)? Are there any iRules active on the virtual server that has problems? 

For example, if ASM is being used, it's good to check if the defaults are being used:
Overview of BIG-IP ASM HTTP response code filtering (f5.com)

[Ashis_K_Patra]

Hi @Niels_van_Sluis  Thanks for your response, 

We have LTM only used and there is an irule which only redirects based on the source IPs and hostnames to a particular pool member.

And now I could see post troubleshooting by doing a curl to below URLs 

1) For working URL its giving HTTP 1.1 response. and its working.
2) For Non working URL direclty(bypassing f5) we can see the HTTP response code is 205 on HTTP/2.
3) For Non-Working URL via LB its giving us ssl error and we believe this is because we are getting response code on 205 via HTTP/2 and as we know HTTP/2 works only over TLS and we dont use serverssl.

[Niels_van_Sluis]

Hi @Ashis_K_Patra,

I don't have a lot experience with HTTP/2 yet, but here I read that HTTP/2 doesn't require TLS.
HTTP/2 Frequently Asked Questions (http2.github.io)

Do you use a HTTP-profile on your virtual server? Maybe you can test if disabling the HTTP filter for a site that doesn't work has a positive effect. See: HTTP::disable (f5.com)

[Niels_van_Sluis]

And another thing you can try is changing the TCP-profile to f5-tcp-progressive. I've encountered problems with some websites to solve when using this relative new TCP-profile.

See: Stop Using the Base TCP Profile! - DevCentral (f5.com)

F5 Unveils New Built-In TCP Profiles - DevCentral