Linux – sendmail: add domain to local usernames, masquerade hostname

emailemail-serverlinuxsendmailUbuntu

I would like to send mails to local users (mail username -s test <<< "test") and let sendmail add the domain. Sending mail to the full address (mail username@domain.tld -s test <<< "test") works, but if I only specify username then the mail is send to username@hostname.domain.tld which is not valid.

I read about masquerading and added this to /etc/mail/sendmail.mc:

MASQUERADE_AS(`domain.tld')dnl
FEATURE(`masquerade_envelope')dnl
FEATURE(`masquerade_entire_domain')dnl
FEATURE(`always_add_domain')dnl
MASQUERADE_DOMAIN(`hostname')dnl
MASQUERADE_DOMAIN(`hostname.domain.tld')dnl
MASQUERADE_DOMAIN(`domain.tld')dnl

restarted sendmail (sendmail.cf is automatically rebuild) but /var/log/mail.log still tells me that sendmail sends to the address with the hostname included.

How can I add @domain.tld to local usernames?

Edit

Requested output:

# as username
$ /usr/sbin/sendmail -Ac -bv username
Notice: -bv may give misleading output for non-privileged user
username... deliverable: mailer relay, host [127.0.0.1], user username@hostname.domain.tld

Best Answer

It turned out that the masquerading options need to be placed in /etc/mail/submit.mc. These were all the lines needed:

MASQUERADE_AS(`domain.tld')dnl
FEATURE(`masquerade_envelope')dnl
MASQUERADE_DOMAIN(`hostname')dnl

Regenerate submit.cf if that isn't done automatically for you and restart sendmail and it works.

Related Solutions

Configuring sendmail to redirect all e-mail to a single user

Please do yourself, and the world, a favour and replace Sendmail with something easier to configure and maintain, like Exim or Postfix. I would normally vote down answers that said "use a different product", but in the case of Sendmail, I think it's worth the risk. Sendmail is very complex to configure compared to modern MTAs and should only be used if you have an existing complex Sendmail infrastructure and you have considerable Sendmail experience.

Also, I don't know if it's a typo or not, but you have

m4 /etc/mail/sendmail.mc > /etc/mail/endmail.cf

Notice the endmail.cf, rather than sendmail.cf.

Centos – Disable local delivery in Sendmail

What I did to disable local delivery. I'll be using the example.com domain.

Requirements:

example.com A entry pointing to IP address assigned to one of the eth interfaces.
/etc/hosts defining example.com assigned to the very same IP address as above
example.com MX records pointing to Google servers (ASPMX.L.GOOGLE.COM, etc)
default sendmail installation (mine was on Ubuntu)

Steps:

vim /etc/mail/sendmail.mc

at the end:

define(`MAIL_HUB', `example.com.')dnl
define(`LOCAL_RELAY', `example.com.')dnl

and then:

sendmailconfig (or /etc/mail/make depending on your distro)
service sendmail restart

testing:

echo -e "To: user@example.com\nSubject: Test\nTest\n" | sendmail -bm -t -v
echo -e "To: user\nSubject: Test\nTest\n" | sendmail -bm -t -v

You should see it connecting to the google server and then you should see your mail being delivered to your Google inbox.

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