Remote Sendmail

[Matthew Carpenter]

Hi Tim-
Your machine needs to be named something that resolves in DNS.  When email servers check for valid email, they will often verify that the sending email domain exists.  Yours, according to this email, is "localhost.localdomain"  pretty typical for a Red Hat install.  

* Both Postfix and Sendmail allow the manual setting of the domain name for outgoing mail.  Set this to something that resolves (like @myschool.edu).

* Or, both Postfix and Sendmail allow for outgoing address mapping.  Postfix calls it "sender_canonical" and sendmail calls it "genericstable" but RedHat doesn't include it in the default config.  

If you are using Sendmail on Red Hat, you'll probably wish to use the first option.  Assuming you know nothing about m4, we'll make the configuration change directly to the sendmail.cf file (often in /etc/mail, but possibly just in /etc).  Look for the following (or similar):
#Dj$w.Foo.COM

And make it:

Djmyschool.com

If you wish to always use your school's email servers as your first relay (if they allow that from your network or host address), you may also look for:

DS

and make it:

DS153.23.53.44   (whatever your school's mail server address or name is)

Hope this helps.  If you do NOT use your school's or ISP's mail server as the first relay (aka "Smart Host"), you may wish to have your IP address (if NAT'ed you'll want the public IP address) resolve both forward and backward by whoever owns the IP range.  They are getting tougher and tougher on SPAM and Dynamic addressing is one big killer.  Most systems allow delivery only from permanent hosts, and even they have to jump through hoops like DNS resolution and possibly even being an MX record for a given email domain...

Good luck!



On Tue, 9 Dec 2003 22:58:28 +0000
"Tim Raggatt" <raggtimejunky at tiscali.co.uk> wrote:

> 
> 
> >-- Original Message --
> >Date: Tue, 9 Dec 2003 13:30:40 -0500 (EST)
> >From: Net Llama! <netllama at linux-sxs.org>
> >To: linux-users at linux-sxs.org
> >cc: linux-users at smtp.linux-sxs.org
> >Subject: Re: Remote Sendmail
> >Reply-To: linux-users at linux-sxs.org
> >
> >
> >On Tue, 9 Dec 2003, Tim Raggatt wrote:
> > Hi,
> >
> > I'm a bit of a newbie, so bear with me!
> >
> > I have a remote email account with my college and I want to set my computer
> > at home up so that I can send mail through it. I've already managed to
> set
> 
> >> up mutt to access it using IMAP, but when I send a mail from my machine,
> > it has the wrong source IP in it (ie. mine, rather than my colleges),
> which
> > causes some mailservers to treat it as spam! How can I set it all up so
> > that it contains the
> >correct IP? (I figured it would mean accessing sendmail
> > on the remote server??)
> >
> > If anyone could help, that'd be great!
> 
> I'm somewhat confused by your setup.  Are you using your box, or your
> college's SMTP server as the MTA?  Do you really m
> >an IP (address), or do
> you mean domain name?  And can you give an example of the wrong & correct
> result?
> 
> Here's the email I got back from the uni when I tried to send an email to
> my uni account (from home, through my uni account). I assume it has something
> to do with the error 550 "Sender verify failed"...
> 
> 
> >From MAILER-DAEMON at localhost.localdomain  Mon Dec  8 00:34:30 2003
> Return-Path: <MAILER-DAEMON at localhost.localdomain>
> Received: from localhost (localhost)
>     by localhost.localdomain (8.12.8/8.12.8) id hB80YUlO004725;
>     Mon, 8 Dec 2003 00:34:30 GMT
> Date: Mon, 8 Dec 2003 00:34:30 GMT
> From: Mail Delivery Subsystem <MAILER-DAEMON at localhost.localdomain>
> Message-Id: <200312080034.hB80YUlO004725 at localhost.localdomain>
> To: <raggatt2 at localhost.localdomain>
> MIME-Version: 1.0
> Content-Type: multipart/report; report-type=delivery-status;
>     boundary="hB80YUlO004725.1070843670/localhost.localdomain"
> Subject: Returned mail: see transcript for details
> Auto-Submitted: auto-generated (failure)
> Status: RO
> Content-Length: 1928
> Lines: 57
> 
> This is a MIME-encapsulated message
> 
> --hB80YUlO004725.1070843670/localhost.localdomain
> 
> The original message was received at Mon, 8 Dec 2003 00:34:30 GMT
> from timbox [127.0.0.1]
> 
>    ----- The following addresses had permanent fatal errors -----
> <raggatt2 at cs.man.ac.uk>
>     (reason: 550-Verification failed for <raggatt2 at localhost.localdomain
> >)
> 
>    ----- Transcript of session follows -----
> ... while talking to t8.cs.man.ac.uk.:
> >>> DATA
> <<< 550-Verification failed for <raggatt2 at localhost.localdomain>
> <<< 550-Unrouteable address
> <<< 550 Sender verify failed
> 550 5.1.1 <raggatt2 at cs.man.ac.uk>... User unknown
> <<< 503 valid RCPT command must precede DATA
> 
> --hB80YUlO004725.1070843670/localhost.localdomain
> Content-Type: message/delivery-status
> 
> Reporting-MTA: dns; localhost.localdomain
> Received-From-MTA: DNS; timbox
> Arrival-Date: Mon, 8 Dec 2003 00:34:30 GMT
> 
> Final-Recipient: RFC822; raggatt2 at cs.man.ac.uk
> Action: failed
> Status: 5.1.1
> Remote-MTA: DNS; t8.cs.man.ac.uk
> Diagnostic-Code: SMTP; 550-Verification failed for <raggatt2 at localhost.localdomain>
> Last-Attempt-Date: Mon, 8 Dec 2003 00:34:30 GMT
> 
> --hB80YUlO004725.1070843670/localhost.localdomain
> Content-Type: message/rfc822
> 
> Return-Path: <raggatt2 at localhost.localdomain>
> Received: from localhost.localdomain (timbox [127.0.0.1])
>     by localhost.localdomain (8.12.8/8.12.8) with ESMTP id hB80YNlO004723
>     for <raggatt2 at cs.man.ac.uk>; Mon, 8 Dec 2003 00:34:30 GMT
> Received: (from raggatt2 at localhost)
>     by localhost.localdomain (8.12.8/8.12.8/Submit) id hB80YMLt004721
>     for raggatt2 at cs.man.ac.uk; Mon, 8 Dec 2003 00:34:22 GMT
> Date: Mon, 8 Dec 2003 00:34:22 +0000
> From: Tim Raggatt <raggatt2 at cs.man.ac.uk>
> To: raggatt2 at cs.man.ac.uk
> Subject: hoho!
> Message-ID: <20031208003422.GA4715 at cs.man.ac.uk>
> Mime-Version: 1.0
> Content-Type: text/plain; charset=us-ascii
> Content-Disposition: inline
> User-Agent: Mutt/1.4i
> 
> hosdfksdj hoho!
> 
> --hB80YUlO004725.1070843670/localhost.localdomain--
> 
> 
> 
> 
> 
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