Configure sendmail for SMTP relay with your ISP

2009-09-26 4 min read Linux

I have copied the document from the above link without modifications

Author: Sven Knispel
Updated: 05-01-2005
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The following article explains the setup of sendmail for forwarding mails to your ISP’s smtp server.
It is assumed that you have sendmail up-to-date and configured properly.
_Note: this setup does not work properly for smtp-server using

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      SASL
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(e.g. like

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      smtp.pobox.com
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)
Most of the commands must be executed with the corresponding rights (using

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      sudo
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1. configure your smtp-server

(this requires that you have the package

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      sendmail-cf
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installed)

1.1. changes to

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      /etc/mail/sendmail.mc
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Uncomment the definition

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      SMART_HOST
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and add the correspondign

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      FEATURE
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to it:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; define(`SMART_HOST\', `your-smtp-server\')<br /> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;FEATURE(authinfo)dnl
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Note: Please note, that these are ”oriented” quotes.

1.2. create the new

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      sendmail.cf
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Stop sendmail by issuing the command

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      /sbin/service sendmail stop
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and log on as

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      root
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to issue this command.

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
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      &nbsp;
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1.3. Define the account information for connecting to the smtp-server

Edit/create

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      /etc/mail/authinfo
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and add the following line:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; AuthInfo:<your-smtp-server> "U:<your-smtp-user>" "P:<your-smtp-password>" "M:DIGEST-MD5"
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_Note:_The

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      M:
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may vary depending on the capabilities of the smtp-server (e.g.

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      CRAM-MD5, PLAIN
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Create

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      authinfo.db
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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; makemap hash /etc/mail/authinfo < /etc/mail/authinfo
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and finally restart sendmail:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; /sbin/service sendmail restart
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1.4. Configure header rewriting (optional)

Header rewriting consists in replacing the

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      From:
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and

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      Reply to:
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in the header of an outgoing mail in order for the recipient to reply to a valid address.
This can be set by editing the file

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      /etc/mail/userdb
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      <local-name>:mailname <email-adsress>
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E.g.:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; # /etc/mail/userdb <br /> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;sven:mailname sven@foo.org
    </div>
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Finally create the corresponding database:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; makemap btree /etc/mail/userdb.db < /etc/mail/userdb
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… and finally restart sendmail:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; /sbin/service sendmail restart
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1.5. Test your settings

Issue following commands and check the trace for verifying the delivery path:

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; /usr/sbin/sendmail -bv root@localhost
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Should show a ”local” delivery.

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      &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; /usr/sbin/sendmail -bv <your-mail>@<your-domain>
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Should show a delivery path through your ISP.

For troubleshooting you should check the mail-log:

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      /var/log/maillog
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2. Forwarding

Forward can be defined in

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      ~/.forward
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. (just enter the e-mail addressto forward to). _Note:_The permissions of that file must be adjusted correspondingly in order to avoid sendmail ignoring it (see

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      /var/log/maillog
    </div>
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in case of problems).

3. References

For further information I recommend to check following link:

<a linkindex="3" href="http://www.pl-berichte.de/work/server/mailserver.html">http://www.pl-berichte.de/work/server/mailserver.html
<a linkindex="4" href="http://www.sendmail.org/%7Eca/email/auth.html">http://www.sendmail.org/~ca/email/auth.html