http://ds2.internic.net/cgi-bin/dns.pl?name=netscape.com&type=MX
# telnet xwing.netscape.com smtp
220 xwing.netscape.com ESMTP Tue, 22 Jul 1997 11:04:33 -0700 (PDT)
ehlo...
250-xwing.netscape.com Hello...
help
214-This is Sendmail version 8.8.5
http://ds2.internic.net/cgi-bin/dns.pl?name=lotus.com&type=MX
# telnet lotus.com smtp
220 lotus.lotus.com Sendmail SMI-8.6/SMI-SVR4 ready at Sat, 23 Aug 1997
20:44:32 -0400
http://ds2.internic.net/cgi-bin/dns.pl?name=microsoft.com&type=MX
# telnet mail1.microsoft.com smtp
220 mail1.microsoft.com Microsoft Exchange Internet Mail Service
5.0.1458.49 ready
[* HINT: Sendmail <http://www.sendmail.org> is the most popular
*public-domain* mail server. *]