Unacknowledged fin/ack - should I use loose close?

All,

 

I have a weird scenario where I'm using an LTM at 11.5.2 HF1 to proxy HTTP over a non-standard port. If the client talks directly to the server, all is well - even under a load test. When proxied by the LTM, the load test sees java reset errors.

 

I did the obligatory packet capture and found that on the server side, after the process is complete, the connection is shut down and looks normal. But on the client side, the fin/ack is not ack'd by the client. So the LTM VIP tries it 4 more times and then sends RSTs on both sides. I don't have a capture on the client to verify if the fin/ack got there or not. I'll need to get with the group that owns the client and get that.

 

Feeling the need to do something quicker, I change the tcp VIP to a fast layer 4 w/ loose close enabled. This seems to work, but I'm not sure if it's a good idea. What kind of fallout might I expect it I propose this FL4 profile as a solution? Sometimes a quick fix isn't really a good idea, what do you think?

 

Thanks, Mike