Agreed that it's too restrictive. FWIW we have been using this in
production. It was based on careful checking of the various RFCs
(though I've just noticed it should also restrict the domain name to
255 characters):
_email_rgx =
Charlie Clark wrote at 2006-10-20 15:50 +0200:
...
There is a module for testing domains against a DNS
which is much more reliable. Regarding the rest I normally check with
the responsible MX server as negatives are usually reliable.
DNS queries can take quite a long time -- and we have seen
