Accessing Internet slow after installing windows 2008

[chicagotech]

Situation: The client just installed windows 2008 server as their first domain controller. After that, accessing the Internet is very slow.

Troubleshooting: 1. Test MTU. It's OK.
2. Upgrading the NIC driver on the server.
3. Nslookup shows no errors.
4. All computers in the office have the same problem.
5. if we switch the DNS from the server to the router, the problem disappears.
6. After checking the DNS settings, we found the problem is the DNS Forwarders was setup to use the router IP.
7. Fixed: delete the router IP from the DNS forwarders and add the ISP DNS.

[chicagotech]

Also check this post: Troubleshooting Internet slow issues - viewtopic.php?f=1&t=9326&p=14470#p14470