Forum Discussion

John_McCulloch's avatar
John_McCulloch
Icon for Nimbostratus rankNimbostratus
Jul 01, 2021

Blocked 'Reverse Connections'

Hi all,   Recently we have ran into an issue with connections that involved our BIGIP devices and client server connections when there is a firewall as man in middle. The issue that is seen prese...
application delivery
BIG-IP
LTM
security
Nikoolayy1's avatar
Nikoolayy1
Icon for MVP rankMVP
Jul 01, 2021

Maybe it is not the same but I had issue that the F5 and the servers may have different time_wait for connection reuse as for f5 is 2 seconds by default and you may change this for the newer tcp profiles to match the servers as their time_wait could be bigger or smaller (for windows servers it is much bigger):

 

 

https://support.f5.com/csp/article/K29377715

 

 

 

For fastl4 there is still no such option and adding a SNAT pool with many ip addresses and maybe preserve the source port for SNAT:

 

 

 

https://support.f5.com/csp/article/K14400019

 

 

 

 

 

Also randomizing the ports helps but this are system variables, so be carefull:

 

 

https://support.f5.com/csp/article/K8246

 

 

https://support.f5.com/csp/article/K46113533