Re: double ACKs ? some connections hang ...

Pat Crean (
Sat, 06 Apr 1996 09:44:24 -0500

I've been having very similar problems --- here I've got a 1.3.7/8.* system
acting as a terminal server and 1.3.6/7/8.* mail server --- pop3 connections
to the mail server from a ppp connection on the term server frequently slow
down or hang completely --- tcpdump shows duplicate or never-ending acks
from mail server.

At 02:25 PM 4/6/96 +0200, you wrote:
>I've been working with 1.3.68 on my machine at home, but moved to 1.3.83
>since I experienced some network problems. however, 1.3.83 has the same
>problems, namely:
>when I use the cern-httpd as a proxy server, then, for some other internet
>hosts, the connection will hang. I suspect this could be because of
>double ack-packets. I verified that with 1.2.13 there aren't these kind
>of problems. tcpdump , when used with a 1.2.13 kernel, will not show
>duplicate acks.
>so, when I type:
>> root@ferkel # telnet localhost 80
>> GET
>the connection will hang, and tcpdump will show the following traffic:
>(NB: slip0 = my host at home, linux-1.3.83, ist-gw = the gateway on the
> other side running linux-1.2.13)