From owner-freebsd-net  Wed Apr 10  6: 7:57 2002
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Reply-To: <ank@bigpond.net.au>
From: "Arkadi Kosmynin" <ank@bigpond.net.au>
To: <freebsd-net@FreeBSD.org>
Subject: Need help. A system stops responding to network requests periodically. 
Date: Wed, 10 Apr 2002 23:06:09 +1000
Message-ID: <OPEKLGNIBDIHJCIEIOPFGEJFCPAA.ank@bigpond.net.au>
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Hello people,


I really can not explain this. We are stress testing a server. We use the
following configuration: the server runs on a FreeBSD box (or Linux, with a
similar effect). A multithreaded tester program runs on a Win2K box and
emulates random multiuser activity. The FreeBSD box stops responding to
network requests every 20-30 minutes. I can't even connect to its FTP
server. If I don't touch it, it does not "unstuck" for quite a while. But,
if I do something with it, like start a Web browser on it and access the
server, or just do netstat, it became active again shortly.

Can anyone explain this? Is it some form of protection from denial of
service attack? The tester program generates a lot of requests, and does it
very fast, so, it does look like an attack.

We do use SO_REUSEADDR option on the server sockets, so, this is covered.
Any ideas? Any recommendations?


I would really appreciate some help. We don't have any other problems with
this server so far, but this one.


Thanks in advance,


Arkadi.


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