D. J. Bernstein
Internet mail
qmail
Frequently asked questions

How to solve problems

What should I do if I have trouble with qmail?

Answer: Read the documentation! Most questions are answered by

this list of frequently asked questions;
the qmail pictures, which show how qmail handles various types of messages;
the other how-to pages in /var/qmail/doc; and
the qmail manual pages in /var/qmail/man/cat*.

Your system includes a wide variety of monitoring tools to show you what qmail is doing:

the qmail log, as introduced in /var/qmail/doc/TEST.*;
instcheck (in the qmail install directory), which looks for installation problems;
qmail-showctl, which explains your current configuration;
dot-forward -n (if you have installed dot-forward), which lets you see how a .forward file will be interpreted;
fastforward -n (if you have installed fastforward), which lets you see how a forwarding table will be interpreted;
ps, which lets you see what processes are running;
recordio (if you have installed ucspi-tcp) and tcpdump, which let you see what data is flowing over a TCP connection; and
a syscall tracing tool, trace or truss or strace or ktrace, which lets you see exactly how a program is interacting with the system.

If all else fails, you could try asking for help on the qmail mailing list. Your message should give complete answers to the following three questions:

What exactly did you do?
What exactly did the computer do?
What exactly did you expect the computer to do?

For checkpassword and other POP password checkers you should instead try the password mailing list. For serialmail and other part-time-dialup questions you should instead try the serialmail mailing list.

Is there commercial support for qmail?

Answer: Yes. See www.qmail.org.

Where can I find technical information about Internet mail?

Answer: cr.yp.to/im.html explains the Internet mail infrastructure. cr.yp.to/smtp.html explains the Simple Mail Transfer Protocol. cr.yp.to/immhf.html explains the Internet mail message header format.