Re: RE: Retransmissions seen for HTTP GETs and POSTS

[Ben Ricker <ben.ricker@xxxxxxxxx>]

TCP retransmissions are not related to Apache; it is an OS/network issue and you need to focus on the server interface configuration or the network(s) between the client and the server. There is a good, succinct troubleshooting guide here: http://acs.lbl.gov/TCP-tuning/troubleshooting.html

You might be looking at a network load issue or need to tweak the TCP retransmission timeout setting. But again, the issue is on the TCP/networking layer and not an issue with Apache.

Good luck.

-- 

Thanks,

Ben Ricker

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I use my cat's name for a password: he is called zo4W*!@n32G+ and I change his name every 60 days.

On May 27, 2008, at 4:23 PM, Nayman Felix-QA5535 wrote:

I've posted this before, but since I haven't seen any response and haven't had any success in debugging this, I'm wondering if anyone can provide any insight.  My previous message is below:

 

In some testing that I've done, anywhere from 1 to 10%  of HTTP GETs and POSTs that apache receives are resulting in a TCP retransmission.  I've captured a wireshark trace for these retransmissions and noticed that the HTTP GET  or POST is being received, but no TCP ack is being sent out resulting in a retransmission.  When the retransmission is received, the ack for the initial GET or POST is finally sent back.  Has anyone ever seen such a problem?  I don't see this issue with other TCP traffic so it appears to be related to apache.   These tests were run with Apache 2.2.4 and  on Linux 2.6.21.  If a wireshark trace would be helpful I can provide one.  Thanks for any input.