I've been trying very desperately to track down the source of an issue I'm having with a large SSL request to my Apache server (75K-100K). Every 20 requests or so, when issuing the request in FF, the request hangs. The server is Apache running in Amazon EC2 behind a LB that handles the SSL. (us-east-1)
I'm able to capture the wireshark trace (see http://cloudshark.org/captures/b9425eb191fc ) and I believe what I'm seeing is that the LB becomes unresponsive possibly under load? I see slowness in other browsers but in Firefox, the request often hangs indefinitely.
Notes on the trace file.
Any input on this would be greatly appreciated. Original ideas were issues with the cipher or encryption issues, but I don't see errors in the trace other than normal terminations.
asked 03 Jan '14, 06:42
Chris in Ottawa
edited 03 Jan '14, 10:34
I've been looking at a hung session (tcp.port==64544) in the trace and I think the problem is due to your windows client not retransmitting "in time". In the example below, its retransmission timer increases from 300ms all the way up to 48 secs.
A few observations.
So this behaviour might be a combination of SACK and LSO not working together well. You could try truning it off as described here http://www.peerwisdom.org/2013/04/25/disabling-large-send-offload-windows/
answered 04 Jan '14, 06:41
I couldn't get the capture from the link. In any case did you try to run capture on both side (server and client)? what about fiddler?
answered 03 Jan '14, 10:31