Wesley wrote:
Right I was looking at it differently :)
If there is going to be a check anyway why not put it in your
subscription page
or whatever it is you use and deny the address to be listed with a
waiting period
so "not so friendly" users can't abuse this.
This is problematic:
- it requires implementing mail routing in the subscription page. so
you're going to duplicate mx lookup and transports functionality in
php/perl/python/java/... etc.
- if the system must use specific outbound relays, there is no way to
validate addresses in real time. Many people don't allow smtp
connections from web servers except to specific mail relays.
- what if there is a temp failure? even with ajax, it is still not
possible to "pause" the user (my brain dumps core if it gets a ctrl-z,
except in drunk daemon mode, but then I don't surf the net :)
- it is easier to do more checks offline. no need to worry about latency
and usability.
- in particular, it is easier to fight robots offline.
- if a million users subscribe at the same time, you don't want to start
one million smtp connections in real time. some people don't even check
the domain validity for this reason.
