OpenDNS replaces the DNS lookup service ISP’s provide as a standard to their customers. DNS lookups are being used to translate hostnames (e.g. forum.avast.com) into IP adrdesses (e.g. 70.84.157.228). Users of OpenDNS will use the OpenDNS nameservers for these lookups, so OpenDNS can prevent users from landing unintendedly on a phishing site whentyping a wrong hostname in the browser. OpenDNS now also has a free adult site filter, based onto the Iguard database.
This is good idea, however I cannot recommend usage of this service. It is against philosophy of distributed DNS - their servers are on slower lines than your ISP’s ones and are also more far from you (not geographically, but from the network view). All services that are using DNS (almost all internet services today including web and e-mail) will be slower because of longer DNS respond times.
I have tested and confirm this… slower email and specially browsing…
I would recommend other content filters: Naomi (for children) and K9Webprotection (for anything and anyone, even for phishing).
I use the OpenDNS, primarily for the potential to stop phishing and I find no appreciable difference (I think the additional security is worth any minor slowdown in resolving), however, that is hard to define on dial-up where slow is a way of life ;D
The other thing is my firewall has DNS IP caching so for regular sites visited and the DNS IP returned from OpenDNS are saved this speeds up DNS resolution (or rather avoids it for those you have visited that remain in the cache), so for many of the sites I visit there is no impact, as the IP is in my firewall DNS cache.