Mail to Valid Users Is Bouncing or Disappearing
If you use users/assign as described in Chapter 15, a common mistake is to add a user to the system without updating the users file. Fortunately, this oversight is easily remedied:
# cd /var/qmail/users; make
Delivering Mail on Intermittent Connections
If your qmail system is a hub host for remote systems that connect intermittently by dialup, it is straightforward but messy to deliver the mail while the remote systems are connected.
One approach is to create a flag file in a known directory when a host connects and delete the file when the host disconnects. Then run a script periodically from cron that loops over all of the flag files to push out mail to currently connected hosts.
To flesh out this example, assume there are three dialup hosts called red.example.com, blue.example.com, and green.example.com. Create virtualdomains that give them different virtual domain prefixes:
red.example.com:alias-dial-red
blue.example.com:alias-dial-blue
green.example.com:alias-dial-green
You can put all of the alias-dial mail into one Maildir since the Delivered-To: prefixes keep them separate. To put all the mail for the three hosts into ~alias/dialmail/, create ~alias/.qmail-dial-default containing the line ./dialmail/.
To track the currently connected hosts, put the flag files into ~alias/dialflags and have the dialup connection script create a file with the host's simple name (red, blue, or green) in that directory containing the host's current IP address. Then run this script from cron to push out the mail to whichever hosts are currently connected:
#!/bin/sh
# run this every 15 minutes from cron to push out the mail
cd /var/qmail/alias/dialflags
for hn in *
do
ip=$(cat $hn) # IP address in the flag file
setlock ../$hn.lock \ # lock deliveries to this host
maildirsmtp /var/qmail/alias/dialmail \
alias-dial-$hn- $ip my.example.com 2>&1 |
splogger serial
done
If you also want to push out any waiting mail as soon as a host connects, also put a call to maildirsmtp into the host's connection script. Be sure to use the same lock file to avoid confusion if the cron job happens to run at the same time. If you add another host called purple, you only need to add another line to virtualdomains:
purple.example.com:alias-dial-purple
The remote hosts can use a similar setup to forward their mail to the main host, using a single smarthost entry in virtualdomains.
Code in extra.h to copy everything to log
#define QUEUE_EXTRA "Tlog\0"
#define QUEUE_EXTRALEN 5
Now every message will be copied to the address log, so you can create ~alias/.qmail-log to save the mail:
./logmaildir/
The .qmail file must save the mail but cannot forward it. Why not? Because forwarding mail invokes qmail-queue again, which will redeliver the mail to log, creating a nasty mail loop.
Deleting Stale Mail
cd /home
{
# unread mail over a month old
find /home/*/Maildir/new -type f -mtime +30 -p
# read mail over three months
find /home/*/Maildir/cur -type f -mtime +90 -p
# any mail marked deleted
find */Maildir -type f -name "*:2,*T*" -print
# any mail in Trash/new or cur
find */Maildir/.Trash/??? -type f -print
} | xargs -t rm
Web Sites
There are several excellent sources of qmail information online.
http://cr.yp.to
Dan Bernstein's web site, the official source for qmail and all of his ad-on packages.
http://www.qmail.org
Russ Nelson's qmail resource site, intended to have links to all of the other resources on the Web.
http://qmail.gurus.com
The author's companion site for this book, containing scripts, updates and corrections, links to other resources, and ordering info for more copies.
http://www.lifewithqmail.org
Dave Sill's Life with qmail, an online guide to setting up and using qmail. It offers specific advice about where to install qmail, and where to put all of the files and directories that qmail needs. This is by far the most widely used setup and the one that qmail experts are the most familiar with, so it's the one you should use. The file and directory locations used in this book are consistent with these.
http://www.lifewithqmail.org/ldap/
Henning Brauer's Life with qmail-ldap, a guide to setting up qmail-ldap. Indispensable for qmail-ldap users.
http://www.ezmlm.org
The home page for the ezmlm-idx mailing list manager, with software and documentation.
http://tinydns.org
Russ Nelson's site for Dan Bernstein's djbdns, a DNS package that relates to BIND roughly as qmail relates to sendmail. Not required for qmail, but if you're setting up a DNS server along with your mail server, it's probably the software you want to use.
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