Verifying an email address

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