DNS weirdness
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- Re: DNS weirdness
Re: DNS weirdness
07-07-2009 1:50 PM
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I'm sorry for both the problems you saw last night and foir the lack of a service status posting which was an oversight on our behalf.
Our networks team believe they fixed something this morning and we're hopeful that these issues are resolved. Please do let us know if this is not the case.
Re: DNS weirdness
07-07-2009 4:13 PM
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Quote from: Liam Yep, I'm getting lagging DNS and timeouts again too this morning intermittently.
Quote from: RealAleMadrid I still don't see any service status report for this problem.
Not impressed.
Everything at this side now appears to be working OK so I'm not sure a service status is necessary - unless of course you're still having problems?
Liam, shortly after you made that post we identified that a listener on one of the load balancers wasn't accepting requests for a particular caching DNS server. We restarted the DNS service which seemed to clear this problem.
After a bit more digging we've noticed that one of the gateways was having difficulty talking the master load balancer (for caching DNS requests). Since the 1st July it looks like it's been using the secondary load balancer instead. Interestingly enough this the gateway flipped back to using the master last night which happened around the same time DNS problems were being reported.
We've not got an awful lot to go on at the moment so we're currently making sure we've got better monitoring in place should we see a similar thing happen again.
If you are still having problems then you can help by providing some of the information I asked for a while back in the post here. I've summarised this below:
[quote author="Bob, the last time there were DNS issues"]Firstly, find out what of the 4 DNS addresses you are using. You might already know this however if you don't you should find the information on one of your router's status pages. Failing that, you can run the ipconfig command from a Windows command prompt:
Quote from: ipconfig C:\Users\admin>ipconfig /all
Wireless LAN adapter Wireless Network Connection:
Connection-specific DNS Suffix . : lan
Description . . . . . . . . . . . : Intel(R) PRO/Wireless 3945ABG Network Con
nection
Physical Address. . . . . . . . . : 00-1B-77-C5-37-5E
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::6d63:2b26:cfac:4ead%10(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.65(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 23 April 2009 12:44:41
Lease Expires . . . . . . . . . . : 24 April 2009 12:44:41
Default Gateway . . . . . . . . . : 192.168.1.254
DHCP Server . . . . . . . . . . . : 192.168.1.254
DNS Servers . . . . . . . . . . . : 212.159.13.49 <--- If this shows your router's IP address then you'll need to look on your router status pages for the addresses you're using.
212.159.13.50
NetBIOS over Tcpip. . . . . . . . : Enabled
Secondly, run a traceroute from a Windows command line to each of the DNS addresses. This will tell us both what gateway you're connected to and which of the two loadbalanced sites your DNS traffic is going to.
Quote C:\Users\admin>tracert 212.159.13.49
Tracing route to pth-cdns01.plus.net [212.159.13.49]
over a maximum of 30 hops:
1 89 ms 98 ms 99 ms dsldevice.lan [192.168.1.254]
2 58 ms 49 ms 70 ms lo0-plusnet.pte-ag2.plus.net [195.166.128.72]
3 38 ms 57 ms 36 ms ge0-0-0-504.pte-gw1.plus.net [84.92.4.89]
4 62 ms 52 ms 49 ms te2-2.pcl-gw01.plus.net [212.159.0.185]
5 84 ms 53 ms 47 ms vl63.pcl-lb01.plus.net [212.159.2.252]
6 40 ms 28 ms 31 ms pth-cdns01.plus.net [212.159.13.49]
Trace complete.
Quote C:\Users\admin>tracert 212.159.13.50
Tracing route to pth-cdns02.plus.net [212.159.13.50]
over a maximum of 30 hops:
1 75 ms 99 ms 98 ms dsldevice.lan [192.168.1.254]
2 68 ms 49 ms 55 ms lo0-plusnet.pte-ag2.plus.net [195.166.128.72]
3 72 ms 48 ms 66 ms ge0-0-0-504.pte-gw1.plus.net [84.92.4.89]
4 64 ms 52 ms 48 ms te2-2.pcl-gw01.plus.net [212.159.0.185]
5 30 ms 233 ms 30 ms vl63.pcl-lb01.plus.net [212.159.2.252]
6 271 ms 281 ms 60 ms pth-cdns02.plus.net [212.159.13.50]
Trace complete.
Finally try performing a DNS lookup against each of the DNS addresses using a command line utility like 'nslookup'
Quote C:\Users\admin>nslookup bbc.co.uk 212.159.13.49
Server: pth-cdns01.plus.net
Address: 212.159.13.49
Non-authoritative answer:
Name: bbc.co.uk
Address: 212.58.254.252
Quote C:\Users\admin>nslookup bbc.co.uk 212.159.13.50
Server: pth-cdns02.plus.net
Address: 212.159.13.50
Non-authoritative answer:
Name: bbc.co.uk
Address: 212.58.254.252
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: DNS weirdness
07-07-2009 5:00 PM
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C:\Users\James>tracert 212.159.13.49
Tracing route to 212.159.13.49 over a maximum of 30 hops
1 <1 ms <1 ms <1 ms 192.168.0.1
2 42 ms 41 ms 36 ms 195.166.128.53
3 42 ms 39 ms 40 ms 84.92.3.93
4 39 ms 48 ms 44 ms 212.159.2.124
5 49 ms 45 ms 54 ms pth-cdns01.plus.net [212.159.13.49]
Trace complete.
C:\Users\James>tracert 212.159.13.50
Tracing route to 212.159.13.50 over a maximum of 30 hops
1 <1 ms <1 ms <1 ms 192.168.0.1
2 59 ms 40 ms 42 ms lo0-plusnet.ptn-ag2.plus.net [195.166.128.53]
3 207 ms 47 ms 179 ms gi2-2-204.ptn-gw02.plus.net [84.92.3.93]
4 47 ms 45 ms 44 ms vl55.ptn-lb01.plus.net [212.159.2.124]
5 39 ms 38 ms 41 ms pth-cdns02.plus.net [212.159.13.50]
Trace complete.
Two things - the tracert was appallingly slow and what happened on the first one
NSlookup worked fine
Ran tracerts again - no problem - speeds back to normal
Re: DNS weirdness
07-07-2009 5:28 PM
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Re: DNS weirdness
07-07-2009 5:29 PM
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Re: DNS weirdness
07-07-2009 8:28 PM
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Interesting that I was still able to download from a site already connected too while not being able to resolve any new sites within my web browser!
Surely Plusnet must realise there IS a problem?
Re: DNS weirdness
07-07-2009 8:33 PM
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Configured my router to use all 4 servers and fall back to querying the root servers if all else fails.
Re: DNS weirdness
07-07-2009 9:04 PM
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Re: DNS weirdness
07-07-2009 9:05 PM
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If it helped click the thumb
If it fixed it click 'This fixed my problem'
Re: DNS weirdness
07-07-2009 9:06 PM
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Just now wondering if it is probably the reason why I also cannot buy a map from TomTom which I have been trying to do for the last few days since Sunday with different failures and they told me nothing was wrong and I have (unfortunately ) sent them a stinking email saying it is their servers!!!
Tonight it as bad as it was last night. I have just blamed my son and made him switch his laptop off as I couldn't even download an update from Malwarebytes as I thought it might be malware. Can't open up pages such as TomTom home page, google and even plusnet. Rebooting the router fixes it for a short time and then it starts to fail again.
It is absolutely unusable as it stands.
Re: DNS weirdness
07-07-2009 9:06 PM
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Edit: If like me you're fed up with the flaky servers, use these ones for OpenDNS: - 208.67.222.222 208.67.220.220
Re: DNS weirdness
07-07-2009 9:11 PM
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Re: DNS weirdness
07-07-2009 9:15 PM
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Quote [adw@skynet ~]$ script
Script started, output file is typescript
[adw@skynet ~]$ cat /etc/resolv.conf
search avatastic.co.uk
nameserver 212.159.6.10
nameserver 212.159.6.9
nameserver 212.159.13.49
nameserver 212.159.13.50
nameserver 10.0.1.1
[adw@skynet ~]$ traceroute 212.159.6.10
traceroute to 212.159.6.10 (212.159.6.10), 64 hops max, 52 byte packets
1 lo0-plusnet.pte-ag2.plus.net (195.166.128.72) 44.558 ms 35.781 ms 33.525 ms
2 ge0-0-0-504.pte-gw1.plus.net (84.92.4.89) 32.009 ms 33.421 ms 34.444 ms
3 te2-2.pcl-gw01.plus.net (212.159.0.185) 32.592 ms 35.813 ms 46.553 ms
4 * * *
5 * * *
6 * * *
^C
[adw@skynet ~]$ traceroute 212.159.6.9
traceroute to 212.159.6.9 (212.159.6.9), 64 hops max, 52 byte packets
1 lo0-plusnet.pte-ag2.plus.net (195.166.128.72) 43.544 ms 34.813 ms 41.876 ms
2 ge0-0-0-504.pte-gw1.plus.net (84.92.4.89) 36.027 ms 36.631 ms 34.951 ms
3 te2-2.pcl-gw01.plus.net (212.159.0.185) 43.899 ms 35.356 ms 34.980 ms
4 * * *
5 * * *
6 * * *
^C
[adw@skynet ~]$ traceroute 212.159.13.49
traceroute to 212.159.13.49 (212.159.13.49), 64 hops max, 52 byte packets
1 lo0-plusnet.pte-ag2.plus.net (195.166.128.72) 40.569 ms 37.281 ms 38.240 ms
2 ge0-0-0-504.pte-gw1.plus.net (84.92.4.89) 33.981 ms 35.896 ms 34.923 ms
3 te2-2.pcl-gw01.plus.net (212.159.0.185) 33.059 ms 38.365 ms 52.488 ms
4 * * *
5 * * *
6 * * *
^C
[adw@skynet ~]$ traceroute 212.159.13.50
traceroute to 212.159.13.50 (212.159.13.50), 64 hops max, 52 byte packets
1 lo0-plusnet.pte-ag2.plus.net (195.166.128.72) 36.174 ms 33.332 ms 34.509 ms
2 ge0-0-0-504.pte-gw1.plus.net (84.92.4.89) 36.023 ms 40.840 ms 36.701 ms
3 te2-2.pcl-gw01.plus.net (212.159.0.185) 35.932 ms 38.286 ms 42.659 ms
4 * * *
5 * * *
6 * * *
^C
[adw@skynet ~]$ exit
Script done, output file is typescript
Looks like there is something down somewhere ...
Re: DNS weirdness
07-07-2009 9:16 PM
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Re: DNS weirdness
07-07-2009 9:19 PM
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ipconfig /flushdns
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