Forum Discussion
neo64_66457
Nimbostratus
NimbostratusSOL 5089 - Disabling default PCP F5 setting to correct Server Time-wait issue
I have a new application and what I am seing is that the F5 closes the TCP session and the Server also responds to close the session (Fin/ fin-ack/ ack) in both directions. However the F5 tries to use the same source TCP port to connect to the server and the server does not respond and issues occur. When we disabled "preserve client setting" global parameter on F5 the issue went away. We are also using fast L4.
Issue with default PCP (preserve client Port)setting on F5
-------------------------------------------------------------------------------------
server <------------SYN-----------F5 Source port 42282
server------------Syn/Ack-------->F5
server<------------ACK------------
Then the session closes normaly with FIN/Fin ack / Ack in both directions
Then SYN keeps going out with same newly closed TCP source port but server does not respond..
Server<----------------SYN-------------F5 Source Port 42282
Server<----------------SYN--------------F5 Source port 42282
By disabling the PCP Global setting all is now working. This was done using bigpipe command ""bigpipe db TM.PreserveClientPort Disable""
Any issues with leaving this as is or are there apps that require the same source port?
hoolioCirrostratus
I don't know of any specific apps which require the source port to be preserved. What protocol are you load balancing?
Aaron
neo64_66457Thank you Aaron, Just HTTP so this should be fine. The concern was that this is a global setting and can impact something in the future but for now it works. Thanks again.