Date: Wed, 09 Apr 1997 15:26:10 +1000 From: Adrian Carter <adrian@apic.net> To: Adrian Chadd <adrian@obiwan.aceonline.com.au> Cc: questions@freeBSD.org Subject: Re: Weird Network Behaviour Message-ID: <3.0.1.32.19970409152610.00823100@mail.apic.net> In-Reply-To: <Pine.BSF.3.95q.970409120606.2430A-100000@obiwan.aceonline. com.au> References: <3.0.1.32.19970409142658.00792100@mail.apic.net>
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At 12:06 9/04/97 +0800, Adrian Chadd wrote: >Had a similar problem a while back.. > >Remote clients are running PPP? Whats their MTU/MRU? Its a devirse range when I say 'remote'. The largest users being hit are our local LAN users, who access the 2.1.5 mail server via 128k ISDN linked with two P50's. The problem also is impacting the dial-up users who connect to several PM25's that are on the same ethernet segment of the 2.1.5 server, and they do not utilise the 128k link at all. The PM's last time i checked wer set to 1500MTU for the PPP, and ditto for SLIP. However, the remote user complaints of 'broken pipe' etc are coming from singapore and malaysian users accessing the site via the internet. Some US users and other AU users have reported the same. As I said... Got me buggered... =) Adrian > >Cya > > >-- >Adrian Chadd | UNIX, MS-DOS and Windows ... ><adrian@psinet.net.au> | (also known as the Good, the bad and the > | ugly..) > > >On Wed, 9 Apr 1997, Adrian Carter wrote: > >> G'Day all. >> >> Got a bit of a weird one here. We are an ISP running pretty much as a >> FreeBSD house, with them being a mixture of 2.1.5's (only one machine, due >> to the fact it is offsite and I havent had the time to go onsite and >> upgrade) and 2.1.7's. >> >> In the last 4 days the machine running 2.1.5 has been sporadically >> 'dropping data'. In that I mean, as an example, If youy try and send a >> message via that machines SMTP port, communication works fine for the HELO, >> MAIL FROM, and RCPT TO. The client then sends the DATA command, and >> according to sendmail logs, the machine reports a 354 message and awaits >> the data. However, the end-user program never see's the 354 message, and >> eventually times out. If you use the same machine, with the same e-mail >> message, and use a different SMTP host, it works fine. >> >> So, its a sendmail problem me thinks... so I recompile, reconfigure, >> cajoule, coax, abuse sendmail for 2 days, all to no avail. During the >> course of all this, its discovered that rcp'ing to the machine any large >> file also timesout. However, in 90% of cases, small files and small e-mails >> go through fine, but I dont see how this relates, because, the CLIENT is >> not seeing the servers 354, which occurs BEFORE it sends the data to the >> server, so at the stage that it is 'breaking' the server is unaware of the >> size of the message. >> >> So its not sendmail me says. So on I go with a kernel recompile. No change. >> Shut down every service on teh machine except qpop and sendmail 8.8.5. No >> change. Now the weirdest bit of all is, reboot the machine, it works ok for >> a while, then 10 - 15 hours after rebooting, it starts doing it all again. >> >> To through anotehr spanner into the works, it appears like another machine, >> running 2.1.7-RELEASE, is doing a similar thing. Users are occasionally >> reporting they FTP in as a real user, they get authenticated, but then they >> get a timeout when ls'ing. Similar situations are happening with the web >> services running on this machine. Access them direct on the LAN, not a >> problem, however, remote users report that a lot of the time they get >> broken pipe or timeout messages. >> >> Wether the two problems are related I am not sure. They seem similar, but >> the problem here is just to diverse. Im no un*x newbie, but its got me >> buggered as to what the problem is. Even the network card's have been >> replaced, the drop cable replaced and even increased RAM, and there is only >> about a .1% collision rate on the ethernet segment. Its jsut so *WEIRD* >> that it is so intermittent and is only related to certain services it >> appears (qpop on the 2.1.5 machine with the sendmail problem works without >> problems, even weeks after a reboot). >> >> Any suggestions or ideas, however trivial, would be appreciated, as I have >> pretty much exhausted all tests I can think off, and the problem still >> exsists. >> >> Thanks all >> >> Adrian Carter >> Sys Admin >> The Asia Pacific Internet Company >> -- >> ************************************************************************* >> *Adrian Carter Email: adrian@apic.net * >> *Systems Administrator URL: http://www.apic.net/ * >> *The Asia Pacific Internet Company Pty Ltd Autoresp: info@apic.net * >> * Internet Access, Web Housing, Mailing List Management * >> * Phone: (+612) 9419-5133 Fax: (+612) 9419-5155 * >> ************************************************************************* >> > > > -- ************************************************************************* *Adrian Carter Email: adrian@apic.net * *Systems Administrator URL: http://www.apic.net/ * *The Asia Pacific Internet Company Pty Ltd Autoresp: info@apic.net * * Internet Access, Web Housing, Mailing List Management * * Phone: (+612) 9419-5133 Fax: (+612) 9419-5155 * *************************************************************************
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