The mmdftailor file is read by every MMDF application on
startup. The location of the file is the only path name that is fixed
into the system and cannot be changed without recompiling; defaults
for other path names are compiled in, but can be changed in the tailor
On the MIPS machines, the location of the MMDF tailor file is
/etc/mmdftailor; on the Suns, it is
A typical MMDF tailor file is constructed of the following sections:
- Host and domain settings.
- In maths, we hide the names of machines in all external mail, so
we set the name and domain to maths.tcd.ie and the local
machine name to that of the machine. This is one place where each
MMDF tailor file differs from the other.
- Alias tables.
- MMDF tables are used for several purposes. Here we define tables
used for aliases and then declare them as alias tables.
- Domain definitions.
- We'll look at domains in more detail later. Note that the order of the
MDMN entries is vital.
- Channel definitions.
- All MMDF messages are received and transmitted via channels.
We'll return later to discuss channels in
more detail. Again, order is important.
- Misc stuff.
- Such as log level settings, message timeouts and so on.
Because of the complexity of the MMDF message
routing process, it is very easy to break things by making
seemingly innocuous changes to the tailor file. In particular, don't
change the order (or the flags) on the domain and channel tables
unless you are sure you know what you are doing. And, test carefully
and thoroughly after any changes. checkaddr -w is a very
useful tool if you need to test changes.
Up to toplevel, on to path names.