|MAIL.LOCAL(8)||System Manager's Manual||MAIL.LOCAL(8)|
mail.local — store
mail in a mailbox
mail.local reads the standard input up to
an end-of-file and appends it to each user's
mail file. The user must be a
valid user name.
The options are as follows:
- Specify the sender's name.
- Don't create a username.lock file while locking the spool.
- For compatibility, request that files named username.lock be used for locking. (This is the default behavior.)
Individual mail messages in the mailbox are delimited by an empty
line followed by a line beginning with the string
“From ”. A line containing the string
“From ”, the sender's name and a timestamp is prepended
to each delivered mail message. A blank line is appended to each message. A
greater-than character (‘
prepended to any line in the message which could be mistaken for a
“From ” delimiter line.
Significant efforts have been made to ensure that
mail.local acts as securely as possible if the spool
directory is mode 1777 or 755. The default of mode 755 is more secure, but
it prevents mail clients from using username.lock
style locking. The use of 1777 is more flexible in an NFS shared-spool
environment, so many sites use it. However, it does carry some risks, such
as attackers filling the spool disk. Some of these problems may be
alleviated by making the spool a separate filesystem, and placing quotas on
it. The use of any mode other than 1777 and 755 for the spool directory is
recommended against but may work properly.
The mailbox is always locked using flock(2)
while mail is appended. Unless the
-L flag is
specified, a username.lock file is also used.
- Used to set the appropriate time zone on the timestamp.
- temporary files
- user's mailbox directory
mail.local utility exits 0 on
success, and >0 if an error occurs.
A superset of
mail.local (handling mailbox
reading as well as mail delivery) appeared in
Version 7 AT&T UNIX as the program
Using quotas in /var/mail can be
problematic if using sendmail(8) as an MTA, since it asks
mail.local to deliver a message to multiple
recipients if possible. This causes problems in a quota environment since a
message may be delivered to some users but not others due to disk quotas.
Even though the message was delivered to some of the recipients,
mail.local will exit with an exit code > 0,
causing sendmail(8) to attempt redelivery later. That
means that some users will keep getting the same message every time
sendmail(8) runs its queue. This problem does not exist
for smtpd(8) users.
If you are running sendmail(8) and have disk quotas on /var/mail it is imperative that you unset the “m” mailer flag for the ‘local’ mailer. To do this, locate the line beginning with “Mlocal” in /etc/mail/sendmail.cf and remove the “m” from the flags section, denoted by “F=”. Alternately, you can override the default mailer flags by adding the line:
to your “.mc” file (this is the source file that is used to generate /etc/mail/sendmail.cf).
|September 16, 2014||Debian|