Troubleshoting DDNS with zoneedit and nslookup

Today I was playing around with some remote services I installed on a server at home.  While using the software, I stared getting connection errors.  I opened up CMD and did a ping of my ddns hostname.  Sure enough I received a wrong IP address.  Now I have ran into a similar issue with zoneedit before when my IP address would renew with my ISP.  It might take a few minutes but DNS is eventually updated and everything would be working again.  This time though I wasn’t getting an IP from the range of my current ISP (lets say 172.x.x.x), I was getting an IP address from the range of my old ISP (142.x.x.x).

So after a few “What the hell is going on here?” ‘s I started going through scenarios.  Was the DNS server at work to fault?  or perhaps the ISP DNS server?  Perhaps it was zoneedit reporting incorrect IPs?

First off I checked my zoneedit account.  After logging in I found that all my ddns records were up to date with a 172.x.x.x IP, so that ruled zoneedit out.

Next I opened up CMD and ran nslookup.  Now nslookup is a pretty handy tool for those who havn’t used it.  Microsoft’s discription of the tool is “Nslookup.exe is a command-line administrative tool for testing and troubleshooting DNS servers” (http://support.microsoft.com/kb/200525).

I started with typing my domain name into the nslookup prompt. Lone behold my correct IP (172.x.x.x) was resolving.  Hold on a second….  I opened another CMD window and pinged my dns address. Sure enough it resolved the proper IP (127.x.x.x).  Always love problems that fix themselves!

Sadly this wasn’t to be the case for long.  I started up the software again but after a while I stared getting disconnects.  “That was too easy” I thought as I pinged my ddns hostname and sure enough it was showing up as 142.x.x.x.

This time I jumped right into nslookup and this time my ddns hostname was resolving to 142.x.x.x.  So I typed in lserver to get a list of the DNS servers my PC is using to resolve IP addresses.  I then typed in lserver 192.x.x.x (the ip of my first DNS server) and tried resolving my dns name, same 142.x.x.x IP.  I went through the list and got the same IP each time.  I then typed in lserver 8.8.8.8 (google’s publicly available DNS server) and tried resolving my ddns name, and I got my 172.x.x.x IP.

So now I though it was a local dns problem.  I changed the order of my dns servers to include google as first reference and went back to my software.  After a little while longer though more disconnects!

Back to nslookup and sure enough setting lserver 8.8.8.8 and then typing in my ddns name was returning the dreaded 142.x.x.x!  The only thing I could think of now was to go back to zoneedit.

Zoneedit uses 2 name servers with your account for redundancy.  I set  lserver server1.zoneedit.com in nslookup and tried resolving my ddns name and got my correct 172.x.x.x.  I then set lserver server2.zoneedit.com and sure enough got back the 142.x.x.x record.  I fired up the support page on zoneedit.com and sent in a trouble ticket explaining that server2 was keeping a cached record for my ddns account.  Hopefully I get a reply soon!

 

UPDATE

 

I did get a reply and zoneedit fixed their server.  I did however had to republish my domain on their web portal to update the problem server with the correct information.