sendmail and SMTP client-side authentication
strick at covad.net
Tue Dec 2 00:02:13 PST 2003
(Please forgive me if you see this twice. I think I may have
accidentally already emailed this without a subject, but I am
not sure. Sendmail is giving me a very hard time these days.)
My ISP assigns my IP address dynamically. For this and other
reasons I have to relay all my outgoing email through my ISP's
SMTP email relay. I tried to enable sendmail SMTP client-side
authentication on my FreeBSD 4.9 system by adding this line to
my sendmail.mc file:
FEATURE(`authinfo', `text -o -k0 -v1 /etc/mail/authinfo')
and creating the file /etc/mail/authinfo with these contents:
AuthInfo:mail.covad.net "U:userid" "P:password"
(of course "userid" and "password" are not the real values).
When my sendmail connects to the email relay, the email relay says
(in SMTP speak):
250-AUTH LOGIN PLAIN
but there is no obvious exchange of authentication information
and my ISP's email relay sometimes rejects my attempts to submit
email for relay. This is a typical SMTP rejection message:
553 sorry, that domain isn't allowed to be relayed thru this MTA (#5.7.1)
Sometimes my email gets through. I don't know why.
When I send email via Netscape, Netscape does authenticate itself
to the email relay.
Note: I did do a "make sendmail.cf" in /etc/mail after changing
the .mc file and I did restart the sendmail daemons before sending
the rejected email. The authinfo file belongs to root:wheel and
has mode 640. I also tried it with mode 644 just in case. I also
tried creating the file /etc/mail/access with the same contents and
doing "makemap hash /etc/mail/access". The sendmail.mc file
contains the standard line:
FEATURE(access_db, `hash -o -T<TMPF> /etc/mail/access')
Can someone who knows how this is supposed to work help me out?
Is there an SMTP authentication protocol that protects the
authentication information from network snoopers?
strick at covad.net
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