DNS Problem

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edwar64896
Posts: 13
Joined: Mon Jan 30, 2006 7:25 pm

Re: DNS Problem

Post by edwar64896 » Tue Aug 12, 2008 6:28 pm

Have reset my modem and am connecting at ADSL2+ now. This appears to have brought both maps.google.com and www.abc.net.au back online, although I am one of these lucky customers that gets better performance/speed on ADSL connection than I do when connecting with ADSL2+...

Swings and roundabouts...

I will leave it on ADSL2+ for now and monitor...

So, the question is, if it works when I am connecting at ADSL2+ but not when I am on ADSL, is there possibly something in the DSLAM that is affecting the downstream router?

M

edwar64896
Posts: 13
Joined: Mon Jan 30, 2006 7:25 pm

Re: DNS Problem

Post by edwar64896 » Wed Aug 13, 2008 12:02 pm

update.

I have reset modem and it is now running in ADSL2+ mode. It was previously running in ADSL mode. (I get better connectivity speeds with ADSL than I do with ADSL2+).
Changing back to ADSL2+ has brought these two sites back for me...

cheers,

Mark.

JingW
Posts: 70
Joined: Wed Sep 19, 2007 3:40 pm

Re: DNS Problem

Post by JingW » Wed Aug 13, 2008 2:40 pm

This issue should be fixed now.

edwar64896
Posts: 13
Joined: Mon Jan 30, 2006 7:25 pm

Re: DNS Problem

Post by edwar64896 » Fri Aug 29, 2008 7:39 am

Andrew,

I'm back experiencing the same issue again, with the same sites.
(It's been happening quite regularly but I have been in and out of state with work so havn't been able to deal with it).

The symptoms are the same as before - any attempt to contact www.abc.net.au and/or maps.google.com ends in tears at

traceroute to www.abc.net.au (220.233.2.169), 30 hops max, 40 byte packets
1 router.greenside.local (172.23.1.1) 4.979 ms 5.106 ms 5.060 ms
2 * * *
3 254.0.233.220.exetel.com.au (220.233.0.254) 70.389 ms 71.360 ms 71.776 ms
4 234.0.233.220.exetel.com.au (220.233.0.234) 71.758 ms 71.742 ms 71.727 ms
5 2.4.96.58.exetel.com.au (58.96.4.2) 71.695 ms 71.728 ms 71.706 ms
6 57.1.96.58.exetel.com.au (58.96.1.57) 71.649 ms 129.043 ms 128.779 ms
7 * * *
8 * * *


I am still (at the moment) running on an ADSL2+ protocol on the router.

evidently, its happening on both ADSL and ADSL2+, so there is no reason to suspect the ADSL2 side of things.

I have tried reducing my MTU, but with no success. What ever I reduce it to, it pops back to being 1492 again.

Resetting my modem seems to temporarily fix the issue, but after a period of time, the sites are gone again.
I know of no other sites - other than the ones mentioned - that I am experiencing the problem with.

Is it possible to probe the router at 58.96.1.57 to see why it is dropping packets from 220.233.83.72?

cheers,

Mark Edwards
0408 601107

SysAdmin

Re: DNS Problem

Post by SysAdmin » Fri Aug 29, 2008 8:52 am

edwar64896 wrote:Andrew,

I'm back experiencing the same issue again, with the same sites.
(It's been happening quite regularly but I have been in and out of state with work so havn't been able to deal with it).
I've asked a network engineer to help you.

Andrew.

JingW
Posts: 70
Joined: Wed Sep 19, 2007 3:40 pm

Re: DNS Problem

Post by JingW » Fri Aug 29, 2008 9:15 am

It's a routing issue related to Akamai BGP.

It was resolved.

edwar64896
Posts: 13
Joined: Mon Jan 30, 2006 7:25 pm

Re: DNS Problem

Post by edwar64896 » Fri Aug 29, 2008 8:11 pm

Hi.

glad to see that we are starting to get to the bottom of this.

Unfortunately, it appears that the use of the term 'resolved' may be somewhat subjective in this context.

Doesn't resemble 'fixed' from my end anyway...

[medwards@phones ~]$ date;traceroute http://www.abc.net.au
Fri Aug 29 20:10:00 EST 2008
traceroute to http://www.abc.net.au (220.233.2.169), 30 hops max, 40 byte packets
1 router.greenside.local (172.23.1.1) 4.325 ms 4.270 ms 4.237 ms
2 * * *
3 254.0.233.220.exetel.com.au (220.233.0.254) 45.218 ms 45.204 ms 45.892 ms
4 234.0.233.220.exetel.com.au (220.233.0.234) 45.877 ms 47.324 ms 49.047 ms
5 2.4.96.58.exetel.com.au (58.96.4.2) 51.662 ms 51.723 ms 52.838 ms
6 57.1.96.58.exetel.com.au (58.96.1.57) 58.551 ms 35.633 ms 39.033 ms
7 * * *
8 * * *
9 * * *
10 * * *
11 *
[medwards@phones ~]$

we're still dying in the same place.

any thoughts on how to go forward from here?

M

ymo
Posts: 295
Joined: Sat Sep 10, 2005 4:36 pm
Location: Wollongong NSW

Re: DNS Problem

Post by ymo » Fri Aug 29, 2008 8:31 pm

It seems to be working fine here at the moment (not that this helps you but it may help localize the problem).

Code: Select all

tracert www.abc.net.au

Tracing route to a1632.g.akamai.net [220.233.2.168]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  192.168.1.254
  2     *        *        *     Request timed out.
  3    15 ms    16 ms    15 ms  254.0.233.220.exetel.com.au [220.233.0.254]
  4    16 ms    15 ms    15 ms  234.0.233.220.exetel.com.au [220.233.0.234]
  5    14 ms    13 ms    14 ms  2.4.96.58.exetel.com.au [58.96.4.2]
  6    15 ms    14 ms    15 ms  57.1.96.58.exetel.com.au [58.96.1.57]
  7    17 ms    15 ms    15 ms  168.2.233.220.exetel.com.au [220.233.2.168]

edwar64896
Posts: 13
Joined: Mon Jan 30, 2006 7:25 pm

Re: DNS Problem

Post by edwar64896 » Fri Aug 29, 2008 8:35 pm

unfortunately this issue is intermittent in nature, but consistent in relation to the router in question.

Fortunately Jing W seems to have a handle on the reason for this behaviour - broken BGP.
Now all I can do is hope it can be fixed or my daily fix of ABC.NET.AU will be hard to come by...

For now, I have reset my router and I am back in. I suspect though, it will be off again in an hour or so.
Does this help to understand what the issue might be?

I can't really determine the mechanism by which this is failing - particularly as the failure occurs over time and can be temporarily fixed by resetting the router...

M

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