Re[2]: [Scottish] Strange DNS problem
Thursday, August 29, 2002, 3:29:10 PM, Ben Thorp spake thusly: >>what does an ifconfig and a route show give when your getting this outage? >>maybe even a dump of netstat -ap might reveal something, BT> I'll tell you next month ;o) Did anything strange happen on 27th September? :) Calummailto:[EMAIL PROTECTED] ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
>So DNS may well be up, you just can't see it - it's the network that's down, >got any crontabs running monthly on the 27th? Not that I can see, although I'll doublecheck >what does an ifconfig and a route show give when your getting this outage? >maybe even a dump of netstat -ap might reveal something, I'll tell you next month ;o) >are your modem >light (dial-up right?) Yes - dial-up >going mental when you are down, is someone dossing >you for a few hours a month? Possibly. Although I don't stay connected when it happens, I just disconnect. So they won't get much joy. mrBen ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
So DNS may well be up, you just can't see it - it's the network that's down, got any crontabs running monthly on the 27th? what does an ifconfig and a route show give when your getting this outage? maybe even a dump of netstat -ap might reveal something, are your modem light (dial-up right?) going mental when you are down, is someone dossing you for a few hours a month? Rgds, Ian -Original Message- From: Ben Thorp [mailto:[EMAIL PROTECTED]] Sent: 29 August 2002 14:05 To: [EMAIL PROTECTED] Subject: RE: [Scottish] Strange DNS problem >You say DNS outage but I'm not sure how you come to that conclusion. Because I don't know what I talking about :o( >Were >you able to resolve names to IP addresses and then unable to reach those >addresses? I was not able to ping addresses. First time round I thought the DNS was out because I couldn't ping the IP address of the server, but this time I realised that I couldn't ping any of the DNS addresses I had. >If so this would not be a DNS failure but sounds more like a >routing problem. Or were you unable to resolve names but could reach any >(previously known) IP addresses? This would be a DNS outage and if you use >names for mail/ping/web then would obviously mean you could not reach those >services (but only because you didn't know the address. How this would >occur if you had 3 DNS servers configured is strange, if one was not >responding then the others whould be used. >Why the 27th of each month? Why >not? Maybe they update user accounts on a monthly basis and it is not a >transparent process, who knows. Remember - now been using 2 ISP (+Freeserve as a test) and none worked. The only thought in my mind was the fact that 27 is the biggest positive number for a signed 5-bit binary word (-28 to +27 if I remember correctly) but this seemed a little far fetched. >MC Ben ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish Scottish Enterprise Network http://www.scottish-enterprise.com Scottish Enterprise are holding their Annual Public Meeting on Tuesday 3 September 2002. If you would like to receive an invitation to this meeting or to your local enterprise company's Annual Public Meeting then click here www.scottish-enterprise.com/annualpublicmeetings Headquarters Address & Contact Numbers 150 Broomielaw 5 Atlantic Quay Glasgow G2 8LU. Tel: +44 (0) 141 248 2700. Fax: +44 (0)141 221 3217 This message is sent in confidence for the addressee only. It may contain legally privileged information. The contents are not to be disclosed to anyone other than the addressee. Unauthorised recipients are requested to preserve this confidentiality and to advise the sender immediately of any error in transmission. ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
>You say DNS outage but I'm not sure how you come to that conclusion. Because I don't know what I talking about :o( >Were >you able to resolve names to IP addresses and then unable to reach those >addresses? I was not able to ping addresses. First time round I thought the DNS was out because I couldn't ping the IP address of the server, but this time I realised that I couldn't ping any of the DNS addresses I had. >If so this would not be a DNS failure but sounds more like a >routing problem. Or were you unable to resolve names but could reach any >(previously known) IP addresses? This would be a DNS outage and if you use >names for mail/ping/web then would obviously mean you could not reach those >services (but only because you didn't know the address. How this would >occur if you had 3 DNS servers configured is strange, if one was not >responding then the others whould be used. >Why the 27th of each month? Why >not? Maybe they update user accounts on a monthly basis and it is not a >transparent process, who knows. Remember - now been using 2 ISP (+Freeserve as a test) and none worked. The only thought in my mind was the fact that 27 is the biggest positive number for a signed 5-bit binary word (-28 to +27 if I remember correctly) but this seemed a little far fetched. >MC Ben ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
>OK - here's a weird one for you. > >Last month I had a funny DNS outage - could connect to my ISP (freenetname >at that point) but couldn't collect mail, or ping/surf any web addresses, >or use IRC. I fiddled for a day, then went to bed. In the morning >everything was ok. > >This month, on the _same_date_ (27th - binary implications?) the same thing >happened. Using a different ISP (ntlworld) although still with the DNS from >freenetname as one of the 3 addresses in /etc/resolv.conf. This month I >have been running Firestarter firewall, but last month I didn't even know >about it. Other than that, everything is the same. And the problem resolved >itself after a day again. > >Any ideas what might be happening? (I'm baffled) > You say DNS outage but I'm not sure how you come to that conclusion. Were you able to resolve names to IP addresses and then unable to reach those addresses? If so this would not be a DNS failure but sounds more like a routing problem. Or were you unable to resolve names but could reach any (previously known) IP addresses? This would be a DNS outage and if you use names for mail/ping/web then would obviously mean you could not reach those services (but only because you didn't know the address. How this would occur if you had 3 DNS servers configured is strange, if one was not responding then the others whould be used. Why the 27th of each month? Why not? Maybe they update user accounts on a monthly basis and it is not a transparent process, who knows. MC ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
Re: [Scottish] Strange DNS problem
Ben, If machines won't respond to pings to their IP numbers then chances are DNS is the least of your problems. If it happens again try pinging something independent like: 216.239.55.100 (google, btw). If it doesn't respond then you have bigger problems than DNS. Thanks, Allan Ben Thorp wrote: > > This time round I tried to ping the 3 nameservers in /etc/resolv.conf - 2 > from ntlworld, 1 from freenetname - and none of them were responding to a > ping: 100% packet loss. I also looked in /var/log/messages and a couple of > other places, but couldn't see much unusual (or rather, that I recognised > as unusual ;o) > > It's probably time I upgraded to Slack 8.1 anyway. > > mrBen > > > [EMAIL PROTECTED] > Sent by: To: >[EMAIL PROTECTED] > scottish-admin@mailmancc: > .lug.org.uk Subject: RE: [Scottish] Strange >DNS problem > > > 29/08/02 12:03 > Please respond to > scottish > > > > andrew wrote: > >On Thu, Aug 29, 2002 at 11:39:17AM +0100, Ben Thorp wrote: > >> This month I > >> have been running Firestarter firewall, but last month I didn't even > know > >> about it. Other than that, everything is the same. And the problem > resolved > > > > Ah, that firewall only works with prodigy internet :-) > > > > Ouch. > > I assume no indication of port 53 packets getting blocked in the kernel > log? > > Maybe it's just random weirdness, Ben, but I'd be tempted to note down a > few key IP addresses (dotted quads, e.g. nameservers, systems which will > respond to pings on your ISPs subnet, systems beyonfd that) to test it > out if it goes down again next month. > > HTH > > Colin > > ___ > Scottish mailing list > [EMAIL PROTECTED] > http://mailman.lug.org.uk/mailman/listinfo/scottish > > ___ > Scottish mailing list > [EMAIL PROTECTED] > http://mailman.lug.org.uk/mailman/listinfo/scottish -- Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
This time round I tried to ping the 3 nameservers in /etc/resolv.conf - 2 from ntlworld, 1 from freenetname - and none of them were responding to a ping: 100% packet loss. I also looked in /var/log/messages and a couple of other places, but couldn't see much unusual (or rather, that I recognised as unusual ;o) It's probably time I upgraded to Slack 8.1 anyway. mrBen [EMAIL PROTECTED] Sent by: To: [EMAIL PROTECTED] scottish-admin@mailmancc: .lug.org.uk Subject: RE: [Scottish] Strange DNS problem 29/08/02 12:03 Please respond to scottish andrew wrote: >On Thu, Aug 29, 2002 at 11:39:17AM +0100, Ben Thorp wrote: >> This month I >> have been running Firestarter firewall, but last month I didn't even know >> about it. Other than that, everything is the same. And the problem resolved > > Ah, that firewall only works with prodigy internet :-) > Ouch. I assume no indication of port 53 packets getting blocked in the kernel log? Maybe it's just random weirdness, Ben, but I'd be tempted to note down a few key IP addresses (dotted quads, e.g. nameservers, systems which will respond to pings on your ISPs subnet, systems beyonfd that) to test it out if it goes down again next month. HTH Colin ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
RE: [Scottish] Strange DNS problem
andrew wrote: >On Thu, Aug 29, 2002 at 11:39:17AM +0100, Ben Thorp wrote: >> This month I >> have been running Firestarter firewall, but last month I didn't even know >> about it. Other than that, everything is the same. And the problem resolved > > Ah, that firewall only works with prodigy internet :-) > Ouch. I assume no indication of port 53 packets getting blocked in the kernel log? Maybe it's just random weirdness, Ben, but I'd be tempted to note down a few key IP addresses (dotted quads, e.g. nameservers, systems which will respond to pings on your ISPs subnet, systems beyonfd that) to test it out if it goes down again next month. HTH Colin ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
Re: [Scottish] Strange DNS problem
On Thu, Aug 29, 2002 at 11:39:17AM +0100, Ben Thorp wrote: > This month I > have been running Firestarter firewall, but last month I didn't even know > about it. Other than that, everything is the same. And the problem resolved Ah, that firewall only works with prodigy internet :-) /ducks Andrew -- Andrew Elwell <[EMAIL PROTECTED]> NEW MOBILE NUMBER: 07890 249969 GPG Key ID: 1A1E108D (available on www.keyserver.net) fingerprint: F9B2 68EB E82E CFED EB05 BFF3 0599 2156 1A1E 108D ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
[Scottish] Strange DNS problem
OK - here's a weird one for you. Last month I had a funny DNS outage - could connect to my ISP (freenetname at that point) but couldn't collect mail, or ping/surf any web addresses, or use IRC. I fiddled for a day, then went to bed. In the morning everything was ok. This month, on the _same_date_ (27th - binary implications?) the same thing happened. Using a different ISP (ntlworld) although still with the DNS from freenetname as one of the 3 addresses in /etc/resolv.conf. This month I have been running Firestarter firewall, but last month I didn't even know about it. Other than that, everything is the same. And the problem resolved itself after a day again. Any ideas what might be happening? (I'm baffled) Ben Thorp (mrBen) [EMAIL PROTECTED] ___ Scottish mailing list [EMAIL PROTECTED] http://mailman.lug.org.uk/mailman/listinfo/scottish
