Date: Sat, 18 Apr 1998 10:55:02 -0500 (CDT) From: mike grommet <mgrommet@ns.insolwwb.net> To: Doug White <dwhite@resnet.uoregon.edu> Cc: George Vagner <kf7nn@mutsgo.dyn.ml.org>, questions@FreeBSD.ORG Subject: Re: bad modem on isp Message-ID: <Pine.BSI.3.91.980418103909.7207B-100000@ns.insolwwb.net> In-Reply-To: <Pine.BSF.3.96.980417150646.1625P-100000@gdi.uoregon.edu>
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Hi guys... read this converstaion and thought I might have a little to add... I am the sysadmin for a small ISP in Arkansas that runs BSDI / FreeBSD and what you have mentioned sounds like something similar to what happened here for a time... At the time we were using USR Total Control NetServer 16's for dial up access.. when setting them up, you specify a range of ips to assign... the box itself takes 1 ip as it is a network device, and then you would think that 16 more would suffice for the 16 dial in lines right? wrong. basically, the netservers needed a buffer of 1 ip number between them because it would assign up to your highest IP number specified +1 Here is an example setup (these nums are purely hypothetical) NET1: 205.55.45.1 Netserver1 NET2: 206.66.45.2 Netserver2 IP Ranges (inclusive) NET1: 205.55.45.100 - 205.55.45.115 16 IPS NET2 205.55.45.116 - 205.55.45.131 16 IPS Which _should_ have been plenty... but what would happen is net1 would assign ip's up to 205.55.45.115 + 1 , thus leaking over into net2s range, causing an IP overlap... If we specified a single ip buffer it worked fine like this: NET1: 205.55.45.100 - 205.55.45.115 16 IPS NOT USED 206.66.56.116 NET2: 205.55.45.117 - 205.55.45.132 16 IPS While I have no idea what hardware your isp is running, this sounds like a possible IP overlap, when I finally squished this little bugger, I was quite vexed with USR for a time, but we have since upgraded to Total Control Hubs and are quite satisfied... The symptoms you mentioned were similar for our clients, but its been well over a year and a half since I had to deal with it... this might not be your problem. It doesnt seem like it could really be a bad modem because if this was the case, you wouldnt be able to ping at all, at least that is what you would think... unless its hosing on some larger packet size than your standard ping (64 bytes right??? hmm) I just read your message below a little closer and it really makes me think that it could be an overlap... you seem to indicate that sometimes you will be connected just fine and this happens? this could be that you were on the overlapping ip first, therefore things worked great, then someone else logged in and was assigned the same ip Gosh. I've rattled on long enough, I hope this is remotely useful ;) Mike Grommet System Administrator, and all around nice guy. Internet Solutions, Inc. http://www.insolwwb.net On Fri, 17 Apr 1998, Doug White wrote: > On Fri, 17 Apr 1998, George Vagner wrote: > > > i wrote to you a few days ago about losing connection > > where i can ping anywhere but cant ftp,http,telnet etc > > anywhere. it happened again today so what i did > > was just disconnected my modem phone line until it lost carrier > > and the system redialed as uasual and all was great again. > > Hm, ok. > > > i have come to the conclusion that there may be a bad modem > > on my providers system and i just happen to dial into this > > modem once in a while and get stuck on it cause it dont hang up > > it just sits there where other modems hang up after a > > random amount of time ~ 1 hour or so. > > Odd. > > > so here is what i want to do... > > > > can you suggest a small program or script that i can enter > > into cron so it will request a http page or something > > and if it fails to return the page then hang up the modem > > and redial or kill ppp and restart it (same result)?? > > Sure, easy, you could use fetch to grab a web page and check it's return > code. If it gets an error or times out it will probably return a code >0 > (have to check the manpage). So something like this: > > #!/bin/sh > > fetch http://your-isps-site.com/ || kill-ppp-command > > > i am keeping a log of all the ip's i connect as so to > > inform the provider of the malfunctioning modem line. > > The times are really important. When you have a bank of 100 modems it's > virtually impossible to find bad modems without some seriously detailed > data. > > Doug White | University of Oregon > Internet: dwhite@resnet.uoregon.edu | Residence Networking Assistant > http://gladstone.uoregon.edu/~dwhite | Computer Science Major > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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