"John Viega" <jtv2j@cs.virginia.edu> wrote:

1. DNS lookup can be slow. People want instant feedback.

People also want correct operation. Seriously, how long can a DNS lookup take? We're talking about subscribing to a mailing list. This is not an operation one does dozens of times a day. If it takes an extra 15 seconds, who cares?

I would say that perhaps the list of domains *should* stay, but not be a requirement. How about, the list gets checked, and gives you a warning but not a fatal error if your address doesn't have one of the listed endings?

By saying you are going to build a file with the names of the top-level domains in it, you are essentially saying you are going to build your own manually maintained DNS cache. Well, DNS already does cacheing. What makes you think you can do a better job of it? If your DNS cache doesn't already have "edu", "com", etc in it, something is very strange. If you seriously only want to check top-level domains (a procedure which have dubious value), you can do it just as well by looking the top-level domain up in the DNS.

Roy Smith <roy@popmail.med.nyu.edu> New York University School of Medicine 550 First Avenue, New York, NY 10016