I added custom DNS addresses:
- 184.108.40.206 (Google DNS)
- 220.127.116.11 (Open DNS)
and DNS lookups became faster and much more available (no more a few minute lag every now and then, and no more need to powercycle router and modem!)
P.S. As a bonus, no more redirect to Comcast's adware if you mistype an address.
Update: to observe Comcast adware phenomenon, try http://www.google.om/