May 011999

Verifying an email address

This morning I was told about a method which can be used to verify a mailing address.   Not all mail servers will accept this command as it can be disabled.

This method make use of the SMTP (Simple Mail Transport Protocol) command VRFY (VeRiFY).  In the following example, we connect to port 25 (smtp).  What I typed is highlighted in bold.

This example shows that the user mike exists but the user xyz doesn’t.

$ telnet smtp
Connected to
Escape character is '^]'.
220 ESMTP Sendmail 8.9.3/8.9.3; 
                         Fri, 30 Apr 1999 15:00:14 -0700 (PDT)
VRFY mike
250 Mike Hoskings <>
VRFY xyz
550 xyz... User unknown
telnet> quit
Connection closed.