Forum Discussion

Nimbostratus

Jul 18, 2024

Capturing Client IP at application Server

Hi Team, I am using Performance(layer 4) type set up. I have two Application servers at backend which are running .net TCP listeners. My application requires Client IP to function properly but af...

application delivery

CA_Valli

MVP

Jul 18, 2024

Hi! I've seen this done before with TCP::options

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

Accessing TCP Options from iRules | DevCentral

Another solution could be modifying network design so that F5 is the default gateway for your servers, or modifying routing on your application servers so that client network is reached through F5, but I can understand this might be tricker if everyting's deployed already.

Vivek100
Nimbostratus
Jul 19, 2024
Thanks for response.

I tried below options in iRule.

Option 28
when CLIENT_ACCEPTED { set opt28 [TCP::option get 28] binary scan $opt28 c ver #log local0. "version: $ver" if { $ver == 34 } { set optaddr [IP::addr parse -ipv6 $opt28 1] log local0. "opt28 ipv6 address: $optaddr" } elseif { $ver == 1 || $ver == 2 } { set optaddr [IP::addr parse -ipv4 $opt28 1] log local0. "opt28 ipv4 address: $optaddr" } }
Option 253
when CLIENT_ACCEPTED { set opt253 [TCP::option get 253] binary scan $opt253 c ver #log local0. "version: $ver" if { $ver == 34 } { set optaddr [IP::addr parse -ipv6 $opt253 1] log local0. "opt253 ipv6 address: $optaddr" } elseif { $ver == 1 || $ver == 2 } { set optaddr [IP::addr parse -ipv4 $opt253 1] log local0. "opt253 ipv4 address: $optaddr" } }

iRule thew validation failure and request did not reach to application. Is there any working sample? or any logs to see what failed here.
Really appreciate your help on hit, thanks a lot.