I had this annoying experience this week on our office network. Gmail would not work on any of the PC's connected in the office domain via the Domain Controller. Before I go on, here is a sketch of the network.
The network consists of a Domain Controller (DC) running Microsoft Windows Server 2008 and 16 other client computers running windows 7, connected via a switch. A cisco ADSL modem is connected to the switch for the internet.
The DC has IP 192.168.50.1 and the DC is also the DNS server for the network.
Since a week, all of a sudden, gmail is not working properly on the network. It opens sometimes, doesn't work and sometimes fails to load. Ping gmail.com works sometimes, sometimes sends 2 packets and sometimes doesn't work at all.
When I change the IP configuration of the client/DC and make the Primary DNS server to the IP of the ISP, gmail works fine. So that means gmail is fine and the ISP DNS is fine... I concluded that something is wrong with the DC which is why gmail is not opening through the DC DNS. But can't figure out what.
Well, I still don't know what went wrong but adding a forwarding address for gmail solved the problem.
For this, you will need the IP of the ISP (Internet Service Provider).
Here's how it is done.
1) Open DNS in Administrative Tools
2) Right Click your Domain
3) Configure a DNS Server
4) Create a Forward Lookup Zone
5) Select "This server maintains the zone"
6) Type in the Zone Name. In this case gmail.com
7) Allow Only Secure Dynamic Updates
8) Select "Yes, it should forward queries to DNS servers with the following IP addresses"
9) Below - Key in the IP address of the ISP and click next to finish
In effect what we are doing is that, we ask the browser to contact the ISP's DNS server directly when it wants to access gmail, thereby by-passing the DC in the office. You could do this for just about any website which is having the above problem. If anyone knows why such an issue could happen at all, out of the blue, do share your ideas in the comments.
Thanks for reading and hope I helped!
Good luck and God Speed! :)
