Question : Problem with internal DNS

I have recently setup an internal DNS Server using Ubuntu Server 10.04 running BIND9.

I have also recently migrated a couple of sites from godaddy to our internal server.

The problem is that some of my users, 3 so far, are having issues. One user is running Vista, the other two are running Windows 7. The issue is that when navigating to our now internal site, my.site.com for example, they are hitting our router's external IP instead of the internal server address.

What's strange is that if you do a "ping my.site.com" or "nslookup my.site.com", they both resolve correctly, using my DNS server.

I checked ipconfig/all, and they are indeed using my DNS server. I've done ipconfig/flushdns as well, no go. An ipconfig/displaydns doesn't even show that the address or site is cached.

I've also attempted to restart the DNS Client service; also a no go. I've even completely stopped it; no go either.

I checked their hosts file: no entry there.

I disabled DNS cachine for Firefox, which seemed to fix it yesterday...but apparently ony for Firefox, since the user tried with IE today and had the same problem. I had to manually type in the URL to get to the page. It would not work if he started typing the URL and then arrowed down to the History entry.

But now today I have two other users who solely use Internet Explorer, and I can not for the life of me fix it this time. I have not restarted their machines, but I should not have to do that, especially since I tried that number yesterday (which fixed it.. yesterday!)

Could it be my DNS Server? Or could there be a pattern with these users using Windows 7/Vista?  Does IE have a DNS cache I don't know about? Is this behavior even normal?

Thanks,

Utterly Confused

Answer : Problem with internal DNS

In the DHCP scope options, it lists my DNS server first, and then an external DNS server. I do not have a slave DNS server for now; just one master.

Here is your problem. Under DHCP scope options you have external DNS servers listed. So, the clients periodically go to outside DNS servers to find INTERNAL Domain services. Wipe all external DNS servers out of DHCP. Then, go to DHCP clients and type IPconfig /release   and    IPconfig renew.

Now your DHCP server will not spit out external DNS servers to the clients.