Problem: Verizon renews DNS every 15 minutes, which the crappy westell modem they gave me couldn't handle, would time out, and I'd lose connection,
Solution: I installed a Linksys router and I have it handle the DNS, no problems since.
Problem: Verizon's DNS servers Died constantly.
Solution: I switched to using OpenDNS (http://www.opendns.org) and no DNS problems since.
I am not saying these aren't the only solutions but they sure helped. Just thought I would share.