Date: Fri, 28 Apr 2000 06:52:32 +0930 (CST) From: james <wabit@adl.ussr.net> To: Eric Withabee <ericwithabee@hotmail.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Network interface hanging on 3.3-RELEASE system Message-ID: <Pine.BSF.4.21.0004280651490.8893-100000@gw.Adl.USSR.net> In-Reply-To: <20000427210353.79863.qmail@hotmail.com>
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I had this problem when my CPU fan was buggered, might be worth looking at
that?
regards
james
On Thu, 27 Apr 2000, Eric Withabee wrote:
> Date: Thu, 27 Apr 2000 17:03:53 EDT
> From: Eric Withabee <ericwithabee@hotmail.com>
> To: freebsd-questions@FreeBSD.ORG
> Subject: Network interface hanging on 3.3-RELEASE system
>
> Hello.
>
> I'm experiencing some strange problems with a 3.3-RELEASE system. It runs
> fine for a few days, then it starts getting a continually increasing number
> of TCP connections stuck in the TIME_WAIT state. The number of connections
> keeps building until it reaches a total of about 4000 TCP connections, then
> the server simply stops responding to any requests from the network. From
> the time the connections start building up to the time the server hangs
> varies from under half an hour to a few hours. Again, once the buildup
> starts, the number of connections in the TIME_WAIT state only increases.
>
> I've been trying to diagnose the problem, but haven't had much luck. I'm
> not sure whether it's due to a bug or not, so I'm posting the question here
> instead of to freebsd-bugs.
>
> The problem started as soon as I took the system live. It replaced another
> FreeBSD system, and took over all its duties. It's primarily acting as a
> mail server (Sendmail 8.9.3 and QPopper 2.53) and a web server (Apache
> 1.3.9). It's also running MySQL 9.33. The server it replaced was a 133MHz
> Pentium, and the new server is a 233MHz Pentium II. The old server did not
> experience this problem -- in fact, it was extremely stable.
>
> I originally thought that it might be the NIC card, a 3Com 3C905B, or the
> "xl" driver, so I replaced it with a Linksys LNE100TX ("mx" driver). This
> seemed to help somewhat, as the duration between occurrences increased from
> a few hours to a few days. However, it continues to occur, and I'm
> wondering if the improvement when I switched the NIC card was just a
> coincidence. Although, since I made the switch, the problem has never
> occurred as quickly as it did with the 3Com card. We've had very good luck
> with 3Com NICs in the past, but this was the first time we'd used a 3C509B
> and the "xl" driver.
>
> The time between occurrences varies significantly. Sometimes, the system
> will run for over a week, while other times it will run for less than a day.
>
> Just in case the problem was related to the number of mbufs, I bumped up the
> default settings so that it has a maximum of 4096 mbuf clusters. It didn't
> help. The system seems to be peak at around 300 mbufs until the problem
> occurs.
>
> I decided to see whether it might be a DOS attack, even though that doesn't
> really make sense, because the problem started as soon as I took the system
> live. At the time the problem is occurring, the connections in the
> TIME_WAIT state don't originate primarily from one IP address. I suppose
> this doesn't rule out a distributed DOS attack, but I think that's pretty
> unlikely.
>
> Here's some specifics about the system:
>
> ASUS P3B-F motherboard
> Intel 233MHz PII
> 128MB RAM
> 2 Western Digital Expert 9.1GB 7200 RPM drives
> Mirrored via an Arco DupliDisk (Bay Mount)
> Linksys EtherFast 10/100 NIC (LNE100TX)
> Adaptec 2940UW SCSI Adapter
> HP SureStore T20i Travan Tape Drive
> Full-tower case with lots of fans
>
> In the meantime, while I've been trying to figure this out, I've got a
> cron'ed a script that checks the number of connections and reboots the
> server if it gets to a stage that indicates that the server has passed the
> point of no return. Before it reboots it, it sends me an e-mail message
> giving the output from a "netstat -n", a "netstat -m" (I just added this
> today), and a "ps -ax". It's an ugly hack, but it's keeping me from getting
> paged at 3:00AM.
>
> Does anyone have any thoughts? Thanks for taking the time to read all this.
>
> Eric
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