SMTP authentication is covered in RFC 2554 which can be found here ...
ftp://ftp.isi.edu/in-notes/rfc2554.txt
amongst other places ...
Details of how it works in sendmail can be found here ...
http://www.sendmail.org/~ca/email/auth.html
This also includes some info on how to make sendmail do the AUTH step to other relays which I think is what you are looking for
I've never done this, but have this on a list of stuff to do to my gentoo box at home...
Good luck
tim
(first post - hope its a good one ...)
(Ted Harding) wrote:
Hi Folks,
I've just received the following from my ISP (BT-yahoo.com):
Subject: Warning: Possible misuse of email address
Dear Sir or Madam,
Your email address has been used to send unauthenticated email through BT mail servers. If you are a BT Yahoo! Internet customer, you must take action by 6.00am on 27th April 2005 if you wish to continue to use BT mail servers.
If you are BT Yahoo! Internet customer Please make a simple change: switch on 'SMTP authentication'. This is usually done by ticking a box called 'My server requires authentication' in your email program settings.
[...]
This particular message was sent to my "efh@nessie.mcc.ac.uk" email address (which is a genuine account on nessie).
I guess this arises because I have my home sendmail configured to masquerade as "nessie.mcc.ac.uk" when sending by SMTP, and "efh" is the user on the home machine from which mail is sent out. (I've been using this setup for years with no problems so far, in order to reconcile (a) being able to mail between my different home machines, and (b) being recognisable to the outside world as a mail originator (since my home LAN is not recognisable outside my LAN).
I.e. the following is the start of a typical SMTP dialogue when initiating sending of a mail:
220 smtp807.mail.ukl.yahoo.com ESMTP
EHLO nessie.mc.ac.uk
250-smtp807.mail.ukl.yahoo.com 250-AUTH LOGIN PLAIN XYMCOOKIE 250-PIPELINING 250 8BITMIME
MAIL From:efh@nessie.mcc.ac.uk
250 ok
RCPT To:someone@somewhere.on.the.net
250 ok ETC
The "EHLO nessie.mc.ac.uk" and "MAIL From:efh@nessie.mcc.ac.uk" are composed by sendmail, which is configured to masquerade in this way (for the reasons above). This has, as I say, worked without a hitch for years.
Now, as you can see, I have been given less than 48 hours to activate "SMTP authentication", after which presumably BT's SMTP servers will no longer accept SMTP from me and I would be unable to use this connection to send email any more.
the version of sendmail on the machine whicj looks after my email with the outside world is
sendmail-8.8.5 from January 1997
and as far as I can see has no provision for anything resembling SMTP authentication.
I've been browsing the web a bit on this topic, and it seems to me that setting it up in Linux is, even now, not straightforward, nor -- depending on your email setup -- even possible.
I would be very grateful for good advice about how to grasp this nettle, while there is still time! (Clearly, the advice given in BT's message above is out of the question for me!)
Also: Is there anywhere I can read what the details of the "SMTP authnetication" protocol are?
Best wishes to all, Ted.
E-Mail: (Ted Harding) Ted.Harding@nessie.mcc.ac.uk Fax-to-email: +44 (0)870 094 0861 Date: 25-Apr-05 Time: 15:59:32 ------------------------------ XFMail ------------------------------
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