We have problems with internet connection speed with our 70 pcs in our company since we migrated the server from Windows Server 2003 to Windows Server 2008. Everytime I clear cache on the Cashed Lookups folders on the DNS servers, the connection speed gets faster. I have to clear cache twice a day everyday for this problem. We never had this problem when we used the Windows Server 2003. I checked the bandwidth on the router and it was in the normal range. I tested the computer which was not in the domain and had no anti-virus software, so that I am suspecting that the DNS server may be the cause.