As of V8.13, sendmail can quarantine messages based on the sender address so that they may be reviewed before being sent (Section 11.1.2 ^[V8.13]). The sendmail program keeps track of the number of messages quarantined by updating the information in the statistics file (24.9.106^[3ed]), while the mailstats program (5.4^[3ed]) summarizes that information.

Prior to V8.13, the output produced by mailstats ended with the column that displayed the number of discarded messages (the msgsdis column). Beginning with V8.13, a new rightmost column has been added (called msgsqur) that shows the number of messages that have been quarantined:

# mailstats
Statistics from Sun Apr  6 09:47:44 2003
 M   msgsfr  bytes_from   msgsto    bytes_to  msgsrej msgsdis msgsqur  Mailer
 0   0       0K           15544     46975K    0       0       0        prog
 3   678     9590K        0         0K        62      0       0        local
 5   21430   264395K      1055      2082K     12969   0       0        esmtp
=====================================================================
 T    22108    273985K    16599     49057K    13031   0       0
 C    28551                          1980                     13031

The msgsqur column shows the number of messages (envelopes), if any, that have been quarantined since the statistics was cleared.

If you upgrade mailstats to V8.13 before you upgrade sendmail, mailstats will produce the following error when run:

mailstats version (4) incompatible with /etc/mail/statistics version (3)

Normally, the makemap program (5.5[3ed]) ignores lines of input that begin with the # character, but this can cause problems because some files use a different comment character. The dig(1) program, for example, produces output that uses a semicolon as the comment character:

;; ANSWERS:
host.domain.com   1845    CNAME   domain.com

To satisfy the need to build database-map files from such input, the -D command-line switch has been added to the makemap program. When you run makemap with the -D command-line switch, makemap will ignore lines of input that begin with a semicolon.

% file.db

Note that, we prefix the semicolon with a backslash to insulate it from interpretation by the shell.

Ordinarily, the vacation program (5.9[3ed]) will only auto-respond to messages that contain the recipient’s address in the To: or Cc: headers. There will be instances, however, perhaps occurring as a result of aliasing or ~/.forward file translation, when mail will be delivered with an address in one of those headers that is something other than the recipient’s address. To illustrate, consider the following aliases file (12.1.1^[3ed]) entries:

root:          bob
bin:           root
sys:           root
webmaster:     root
hostmaster:    root

Here, the system administrator, bob, receives mail that is also sent to root, bin, sys, webmaster, and hostmaster. Normally, vacation will not respond to mail sent to any of these aliases. If bob wants vacation to respond even if the name bob is not found in the To: or Cc: headers, bob may cause it to do so by adding this -j command-line switch to his invocation of vacation in his ~/.forward file:

 |"/usr/ucb/vacation -j bob"

Henceforth, vacation will amend its recipient check^[3] response (when otherwise able) to all messages, no matter to whom each is addressed.

But note, this switch can cause vacation to auto-reply to unexpected addresses so is better limited for use in restricted environments. Instead, when you know all possible addresses ahead of time (as you should, via the aliases file), use the vacation program’s -a switch (5.9.4.1^[3ed]).

There is always a chance that a vacation message will bounce. To prevent that, vacation (5.9^[3ed]) offers the -z command-line switch (5.9.4.13^[3ed]), which sets the return address for the message to be the null address:

<>

If you prefer a different return address, you may use the new V8.13 -R vacation command-line switch to define one. For example:

|"/usr/ucb/vacation -R [email protected] you"

Here, the -R command-line switch causes vacation to mail messages with a return address of [email protected]. Such a return address might be appropriate at a site that has a special address for all bounces.

You can also use this switch to have bounces sent to yourself at a plussed address. That way you can screen such bounces with procmail(1) or slocal(1), using a line like the following in your ~/.forward file:

|"/usr/ucb/vacation -R [email protected] you"