On Sun, 29 Oct 2000 brflgnk@cotse.com wrote:

Quoting "Alex B. Shepardsen" <abs@squig.org>:

Many SMTP servers disable EXPN and VRFY for security reasons, typically by returning failure messages.

True. (Well, most actually return access denied messages.) But in this case, the user most likely doesn't exist. I was on the wrong trail with mail.bend.com. mail.bendnet.com exists as well, and is a sendmail server. Note the successful EXPN operation for "root" on that server, but the failed VRFY and EXPN for mueller. abs@snuffy abs]$ telnet mail.bend.com 25 Trying 199.2.205.69... Connected to mail.bend.com. Escape character is '^]'. 220 X1 NT-ESMTP Server mail.bend.com (IMail 6.04 64563-1) helo squig.org 250 hello mail.bend.com mail from: nobody@squig.org 250 ok rcpt to:mueller 550 unknown user <mueller> rcpt to:mueller@bendnet.com 550 not local host bendnet.com, not a gateway rcpt to:mueller@bend.com 550 unknown user <mueller@bend.com> quit 221 Goodbye Connection closed by foreign host. [abs@snuffy abs]$ telnet mail.bendnet.com 25 Trying 199.2.205.68... Connected to mail.bendnet.com. Escape character is '^]'. 220 mail.bendnet.com ESMTP Sendmail 8.10.0/8.10.0/BENDNET-MX.wh; Sun, 29 Oct 2000 20:08:10 -0800 (PST) helo squig.org 250 mail.bendnet.com Hello adsl-63-202-76-26.dsl.snfc21.pacbell.net [63.202.76.26], pleased to meet you expn mueller 550 5.1.1 mueller... User unknown vrfy mueller 550 5.1.1 mueller... User unknown expn mueller@bendnet.com 550 5.1.1 mueller@bendnet.com... User unknown expn root 250-2.1.5 Spencer Dahl <sdahl@mail.bendnet.com> 250 2.1.5 <vince@blue-box.net> quit 221 2.0.0 mail.bendnet.com closing connection Connection closed by foreign host. [abs@snuffy abs]$ Alexandra