Most ISP's do deliver DNS to their clients but are not experts nor is it their core business to have the fastest and most reliable DNS lookup infrastructure. You will see slow updates on the DNS front, while your friends using another provider where already browsing your pages.
DNS is not only something 040 Hosting supplies for your domain names,
but it is also a part you use on your machine, on default you most
certainly use your Internet Service Providers DNS servers but as
written above, they are not the experts nor is it their intention to
make it the best of the best.
However there is hope, with
openDNS you have a stable, and professional organisation which is its
core business to serve your DNS.
If you have problems with DNS lookups or the speed DNS changes are picked up, give them a try. It's free!
http://www.opendns.com
