DNS Help

suarve · 1 Apr 2009 at 13:07

Hi,

Can't figure this out, so i'll just list exactly what I did:

Moved a website from old web host to new web host
Changed nameservers for domain name to new web host
To avoid downtime I kept the zone file active for the old host and setup everything with my new host.
Later that day, DNS had updated and the site was now poinbnting at the new host ip -a all good.

That was 2 days ago. I've now gone to the client's site in querstion and and old version is loading. Also, when I ping the domain name the ip now points toi the old hosting.

I used some online ping tools and ping ing the site shows the correct ip (E.g. the new hosting). I also get the latest version of the site when viewing it via an online proxy.

Is this just my ISP having some sort of DNS caching issue or am I missing something?

May Thanks

csmager · 1 Apr 2009 at 13:20

Either DNS caching locally or your ISPs DNS server caching it. The TTL on the old zone file will determine how long the DNS server will likely keep the old information until refreshing it.

You could try an ipconfig /flushdns and, if that doesn't fix it, try using a different DNS server to confirm.

mejinks · 1 Apr 2009 at 13:27

I came across this issue with a dlink router that did basic dns caching. I would suggest its that or your ISP, although unlikely after 2 days.

suarve · 1 Apr 2009 at 13:49

mejinks said:
I came across this issue with a dlink router that did basic dns caching. I would suggest its that or your ISP, although unlikely after 2 days.

Well that's weird thing.

I know for a fact the site was working as normal and pointing at the new hosting yesterday as I checked it myself.

Sin_Chase · 1 Apr 2009 at 14:46

What is the client environment?

If its windows check the DNS entries yourself and either update them or manually remove them.

ipconfig /flushdns on the server should propagate down to any clients performing new lookups but you can be doubly sure and do it on clients too.

Does the gateway have a ping tool in its web management? If so, try from there and see what it resolves.

adeq1 · 1 Apr 2009 at 19:42

If the website is using the same domain as the client do on site they may be operating a "split DNS" config. I.e. two nameservers both authoritative for the same domain, one internal one, and one external one.

At some point in time, the admin may have placed an entry in the internal DNS server (quite likely to be in AD) pointing www.company.com to the IP used for the website. Now, despite the fact that the external DNS is all updated, the internal clients are going to this internal DNS server, which thinks its authoritative for company.com, and its just dishing out the address it knows.