Transition of Mail System to the Linux Environment
This document describes changes occurring in the way electronic mail is
delivered at a2i communications. Previously mail was delivered in a
FreeBSD or SunOS environment. After the transition is complete, all
mail delivery will occur in a Linux environment. If you are doing any
type of customized mail filtering, then this document will help you
understand what changes you might need to make in order to keep your
mail flowing without problems.
Although some changes are already occurring, the bulk of the transition
is scheduled for: 1:00 pm, Wednesday, December 11, 2002, San Jose
local time. Almost all of the changes described in this document will
take effect all at once at that time. Please watch our official
announcements in the a2i.announce
newsgroup or the corresponding mailing list for last-minute
Status of this Document
This is now a historical document. The transition described in
this document was completed as scheduled.
Who Should Read This Document
If you use mail only from a pop or imap client, and if you do not ever
log into the UNIX shell, then you will most likely not need to read this
If you do any type of customized mail filtering (e.g., using
procmail), you should read this document.
If you have customized Nojunk(tm) mail filtering by directly editing a
.nojunk.patterns file, then you should read this document.
The Old System
In our old mail system, mail delivery was done in a FreeBSD environment (if
Nojunk filtering was not enabled and if you had no .forward file) or in a
SunOS environment (if Nojunk filtering was enabled or if you had a .forward
file). Also mail arriving for the Nojunk-specific domains was delivered in a
SunOS environment. These Nojunk-specific domains are:
The New System
In the new mail system, all mail delivery occurs in a Linux environment.
The machines on which mail delivery will occur in a Linux environment
Your mail might be delivered on either of these machines.
Here is a summary of differences between the old and new environments.
- No more .forward.bsd files. All mail forwarding
will use .forward files only. Any .forward.bsd file
in your home directory will be ignored by the new mail system.
- Recompilation needed. If you are using any compiled
programs (e.g., programs written in C) for mail filtering, you will need
to recompile these on a Linux machine. There is no need to recompile
interpreted programs (e.g., perl and shell scripts), but you should test
your scripts to make sure they work in our Linux environment.
- Procmail always runs. In the new Linux environment, the
procmail program is always used to do final mail delivery, and any
.procmailrc file in your home directory is always used for
filtering. This is different from the behavior of the old system, in
which procmail ran only if you invoked it from a .forward or
.forward.bsd file or via a pipe statement in a
- Only email addresses in .forward files. In the new
environment, if you wish to feed incoming mail to a program, you may do
so by invoking that program from within a .procmailrc file.
Pipe commands within .forward files are not supported. Also
filenames (for file append) are not supported within .forward
files. You may use only email addresses in a .forward file.
Check any .forward or .forward.bsd file in your home
directory. If there is any ``|'' (vertical bar) character in one of
these files, you are probably running a program which must be moved out
of this file into a .procmailrc file.
- Program locations differ. Program locations in the Linux
environment are not necessarily the same as in the FreeBSD and SunOS
environments. Thus you should verify that all programs invoked in your
files related to mail filtering are valid in the Linux environment.
Where possible, avoid using absolute pathnames, so that procmail can
find the program by simply looking in the standard places. Please note
that the correct location of the sendmail program is now
/usr/sbin/sendmail on all machines, including SunOS, FreeBSD,
and Linux. As a transition aid, we have made the following programs
available in the SunOS, FreeBSD, and Linux environments at exactly the
If you have any scripts that need to invoke these programs with full
pathnames, you may edit them now to use the above pathnames. Then,
when the transition occurs, you will not need to change these pathnames
- Recipient in X-Original-To. In the past, most users relied
on looking for a Received: header in email to find the address of the
recipient. In the new system, a header X-Original-To: will
appear in all incoming email that will identify the recipient address.
- No vacation program. The vacation program
available in the SunOS and FreeBSD environments is not directly
available in the Linux environment. You may get the same functionality
with procmail. Please see the online manual called
procmailex(5), which you can read by typing the command
``man procmailex(5)'' at the UNIX shell on a Linux
machine. Look for an autoreply recipe that works the same way as the
Before the transition, you can test mail delivery in the new Linux
environment by simply sending mail to USER@linux.rahul.net, where USER is
your login name. Such test mail will be delivered in a Linux
environment. For these tests, any .forward and
.forward.bsd files will be ignored, but any
.forward.linux file will be active. No Nojunk processing will
This feature is for pre-transition testing only.
Playing it Safe
The safest way to survive the transition with the greatest chance
of not losing mail is to disable any mail forwarding, any mail
filters, and any Nojunk features, well in advance of the change.
Then all your incoming mail will go into your mailbox.
Then, after the change is completed and the new mail system is
known to be stable, you may carefully re-enable the above features.
If during or after the mail system transition you report a mail problem
to us, this is the sequence of steps that we will follow.
- We will disable any Nojunk filtering that might have been active
- We will move any .forward file in your home directory
to a temporary name such as .forward.SAVE.
- We will then check to see if your mail is being properly delivered
into your mailbox. If it is, the problem will be considered resolved in
the short run. Then you may at your convenience re-enable any Nojunk
filtering or any mail forwarding carefully. (Note: If your account
type does not include a local mailbox, then we will leave your mail
forwarding enabled and we will verify that mail is being correctly
- If any problems related to Nojunk filtering or mail forwarding are
observed, and they appear to be due to a problem in our mail system and
not in your own account-specific files, those issues will be addressed
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