Superticker2 (Mark) wrote: > >If there's a service or utility that can verify a list of email addresses >(prior to a mass operation), please suggest it.
There are some. See for example <http://www.tienhuis.nl/php-email-address-validation-with-verify-probe> or try this google search <http://www.google.com/#q=verify+email+address>. There are problems with trying to do address verification without actually sending mail. The obvious way to verify an address is to send an SMTP VRFY command to the MX of the domain of the address, but these days most SMTP servers either don't implement VRFY or won't accept VRFY from untrusted sources. The alternative is to begin an SMTP dialog with the MX and send MAIL FROM and RCPT TO commands. As long as you don't send DATA, no mail will actually be sent, but this is not reliable. If the MX rejects the RCPT, you may know from the status that the address is bad, but some MXs will accept an invalid RCPT address and not respond with failure until after DATA, and you can't continue to that point if you don't want to actually send mail. For example, consider the following two SMTP sessions $ telnet a.mx.mail.yahoo.com 25 Trying 67.195.168.31... Connected to a.mx.mail.yahoo.com (67.195.168.31). Escape character is '^]'. 220 mta178.mail.ac4.yahoo.com ESMTP YSmtp service ready HELO msapiro.net 250 mta178.mail.ac4.yahoo.com MAIL FROM: <m...@msapiro.net> 250 sender <m...@msapiro.net> ok RCPT TO: <totally_bogus_mark_sap...@yahoo.com> 250 recipient <totally_bogus_mark_sap...@yahoo.com> ok DATA 354 go ahead . 554 Transaction failed: empty DATA not allowed Connection closed by foreign host. and $ telnet a.mx.mail.yahoo.com 25 Trying 67.195.168.31... Connected to a.mx.mail.yahoo.com (67.195.168.31). Escape character is '^]'. 220 mta112.mail.ac4.yahoo.com ESMTP YSmtp service ready HELO msapiro.net 250 mta112.mail.ac4.yahoo.com MAIL FROM: <m...@msapiro.net> 250 sender <m...@msapiro.net> ok RCPT TO: <totally_bogus_mark_sap...@yahoo.com> 250 recipient <totally_bogus_mark_sap...@yahoo.com> ok DATA 354 go ahead From: me To: you body . 554 delivery error: dd This user doesn't have a yahoo.com account (totally_bogus_mark_sap...@yahoo.com) [0] - mta112.mail.ac4.yahoo.com Connection closed by foreign host. -- Mark Sapiro <m...@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan _______________________________________________ Mailman-Developers mailing list Mailman-Developers@python.org http://mail.python.org/mailman/listinfo/mailman-developers Mailman FAQ: http://wiki.list.org/x/AgA3 Searchable Archives: http://www.mail-archive.com/mailman-developers%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-developers/archive%40jab.org Security Policy: http://wiki.list.org/x/QIA9
