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Forum Discussion

Brad_10289's avatar
Brad_10289
Icon for Nimbostratus rankNimbostratus
Apr 05, 2012

PROBLEM: Pool Member Won't Work Through Big IP LTM

Hi all, I was wondering if anyone might have some insight into a strange issue I'm seeing in our environment that I have had zero success in finding any solution or related posted issue about.   ...
application delivery
availability
LTM
TMOS
hoolio's avatar
hoolio
Icon for Cirrostratus rankCirrostratus
Apr 05, 2012
When you add a TCP profile to a virtual server, TMM will complete a three way handshake with the client regardless of the state of the pool so what you're seeing is expected.

 

 

Your first tcpdump shows the server not responding to TMM's connection attempts:

 

 

09:59:23.951673 IP XXX.XXX.XXX.144.28570 > XXX.XXX.XXX.153.http: S 1018696290:1018696290(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

09:59:27.151393 IP XXX.XXX.XXX.144.28570 > XXX.XXX.XXX.153.http: S 1018696290:1018696290(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

09:59:30.351698 IP XXX.XXX.XXX.144.51298 > XXX.XXX.XXX.153.http: S 2956356628:2956356628(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

09:59:33.351467 IP XXX.XXX.XXX.144.51298 > XXX.XXX.XXX.153.http: S 2956356628:2956356628(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

09:59:36.551418 IP XXX.XXX.XXX.144.51298 > XXX.XXX.XXX.153.http: S 2956356628:2956356628(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

09:59:39.751838 IP XXX.XXX.XXX.144.51298 > XXX.XXX.XXX.153.http: S 2956356628:2956356628(0) win 4380 out slot1/tmm0 lis=NOS_Test

 

 

You could run a tcpdump on the server using Wireshark or whatever network monitoring tool you might have on it. That would allow you to check if the SYN packets are making it to the server. Does the server have multiple NICs? If so, do you see the responses going out a different interface?

 

 

Aaron