> What do the following fido mailer options in sendmail.cf
> mean ?
> F=mDMFhu, S=52/31, R=21
> " Nothing can stop an idea whose time has come !!!"
Here is an explanation of what "F=mDMFhu, S=52/31, R=21" means in
your sendmail.cf's fidonet delivery agent definition:
The F section contains the flags which describe a delivery agent's
behavior. Here is a breakdown of what your flags mean:
m = allow delivery to multiple recipients
D = force inclusion of date information in mail header
M = force inclusion of message identification information in mail
F = force inclusion of sender (From) information in mail header
h = preserve case in hostname
u = preserve case for username
This looks pretty reasonable. My flags section also contains the C
flag, which causes sendmail to append a domain to recipients without one
(the domain of the sender. Useful when sending to someone on your own
BBS); and the S flag which causes sendmail to invoke the delivery agent
(in this case ifmail) with the user and group id specified by the U=
equate. If the U= equate is missing or 0 sendmail runs the delivery agent as
root (note: in sendmail versions prior to v8.7, there was no U= equate, so the
S flag causes sendmail to always run the delivery agent as root). I don't
have a U= equate, so ifmail runs as root which seems to be fine for me.
The S section specifies the Sender rewriting rule set, with rule
51 being used for the envelope and rule 31 used for the header. Finally
the R section specifies the Recipient rewriting rule set. In this case
rule set 21 is used for rewriting both headers and the envelope. Look
around in your sendmail.cf file to find these rules and see what they do.
By the way, this information comes from the book "sendmail, 2nd
edition" by Bryan Costales and Eric Allman (who is the author of sendmail)
published by O'Reilly & Associates (ISBN 1-56592-222-0). I strongly
recommend it to anyone who is working with sendmail. It is very thourough
and well written, with many examples.