Episode 19: How can I control whether incoming email is accepted, denied, or relayed when using Sendmail?

The file /etc/mail/access is used to accept, deny, or relay incoming email. This file controls access to users, entire domains, or an entire IP subnet. The first column specifies a user, domain, or subnet. The second column can be one of the following values:




REJECT
rejects the sender with a general purpose message

OK
accepts mail for receipt (not relay)

RELAY
accept mail for relaying

DISCARD
discard the message completely (harsher than reject)

ERROR:550 your message
like REJECT but returns with your specific message


Here is an example /etc/mail/access file:


user@spammer.org REJECT
spammers.net REJECT
204.168.23 REJECT
192.168 OK
virtualdomain.com RELAY
user@domain.com ERROR:550 mail discarded
nobody@ ERROR:550 bad name


After making changes to this file, execute the following for the changes to take effect:


# make -C /etc/mail
# service sendmail restart


For Example:

I add the following entry in /etc/mail/access :

receiver@intinfra.com REJECT
abhi ERROR:550 mail discarded
ajeet RELAY

Then I ran:
make -C /etc/mail
service sendmail restart

When I tried sending mail from user sender@groupinfra.com as:

[sender@Innova ~]$ echo "hello" | mail -v -s "hi" receiver@intinfra.com
receiver@intinfra.com... Connecting to [127.0.0.1] via relay...
220 Innova.intinfra.com ESMTP Sendmail 8.14.2/8.14.2; Sat, 3 Oct 2009 17:39:59 +0530
>>> EHLO Innova.intinfra.com
250-Innova.intinfra.com Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH DIGEST-MD5 CRAM-MD5
250-DELIVERBY
250 HELP
>>> MAIL From: SIZE=47 AUTH=sender@Innova.intinfra.com
250 2.1.0 ... Sender ok
>>> RCPT To:
>>> DATA
550 5.2.1 ... Mailbox disabled for this recipient
503 5.0.0 Need RCPT (recipient)
>>> RSET
250 2.0.0 Reset state
/home/sender/dead.letter... Saved message in /home/sender/dead.letter
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 Innovation1.groupinfra.com closing connection

And When I tried :

[sender@Innova ~]$ echo "hello" | mail -v -s "hi" abhi@intinfra.com
abhinesh@intinfra.com... Connecting to [127.0.0.1] via relay...
220 Innova.intinfra.com ESMTP Sendmail 8.14.2/8.14.2; Sat, 3 Oct 2009 18:46:32 +0530
>>> EHLO Innova.intinfra.com
250-Innova.intinfra.com Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH DIGEST-MD5 CRAM-MD5
250-DELIVERBY
250 HELP
>>> MAIL From: SIZE=47 AUTH=sender@Innova.intinfra.com
250 2.1.0 ... Sender ok
>>> RCPT To:
>>> DATA
550 5.0.0 ... mail discarded
503 5.0.0 Need RCPT (recipient)
>>> RSET
250 2.0.0 Reset state
/home/sender/dead.letter... Saved message in /home/sender/dead.letter
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 Innova.intinfra.com closing connection
[sender@Innova ~]$

So Both the receiver and abhi were discarded but when I tried mailing ajeet
it went successful.

[sender@Innova ~]$ echo "hello"|mail -v -s "I am here" ajeet@intinfra.com
ajeet@intinfra.com... Connecting to [127.0.0.1] via relay...
220 Innova.intinfra.com ESMTP Sendmail 8.14.2/8.14.2; Sat, 3 Oct 2009 18:54:29 +0530
>>> EHLO Innova.intinfra.com
250-Innova.intinfra.com Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH DIGEST-MD5 CRAM-MD5
250-DELIVERBY
250 HELP
>>> MAIL From: SIZE=51 AUTH=sender@Innova.intinfra.com
250 2.1.0 ... Sender ok
>>> RCPT To:
>>> DATA
250 2.1.5 ... Recipient ok
354 Enter mail, end with "." on a line by itself
>>> .
250 2.0.0 n93DOTF2006201 Message accepted for delivery
ajeet@intinfra.com... Sent (n93DOTF2006201 Message accepted for delivery)
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 Innova.intinfra.com closing connection
[sender@Innova ~]$

So It is working for ajeet.