For example, SMTP and UUCP support can be included in your file by using the following two commands:
The delivery agent
M definitions that correspond to
MAILER() commands are kept in the _CF_DIR_/mailer directory
(_CF_DIR_ is described in Section 19.2.1, "Maintain local files with _CF_DIR_").
See Table 19.3 in Section 20.3.2, define() for
a list of all the available agents.
In general, the files in the _CF_DIR_/mailer
directory should never be modified. If one
of the definitions needs to be tuned, use the special keywords
described under the individual equates (see Section 30.4, "The Equates"). For example, the following
modifies the maximum message size (the
M= equate see
Section 30.4.7, M=) for the UUCP agent:
Here, the maximum size of a UUCP message has been increased from the default of 100,000 (one hundred thousand) bytes to a larger limit of 1,000,000 (one million) bytes.
Unfortunately, not all equates can be tuned with m4 defines.
U= equate for the
usenet agent is one example.
To change such a value, you need to copy the original definition, modify
it, and put the modified definition in your local mc file.
For example, to add a
equate to the Usenet delivery agent, you might do the following:
 We are fudging here. The grep(1) won't work because the
Musenetdefinition is split over three lines. Instead, you need to use your editor to cut and paste.
grep -h Musenet mailer/*Musenet, P=USENET_MAILER_PATH, F=USENET_MAILER_FLAGS, S=10, R=20, _OPTINS(`USENET_MAILER_MAX', `M=', `, ')T=X-Usenet/X-Usenet/X-Unix, A=USENET_MAILER_ARGS $u
Here, the prototype definition for the
usenet delivery agent is found.
Copy that definition into your mc file and add the missing equate:
MAILER(usenet)dnl MAILER_DEFINITIONS Musenet, P=USENET_MAILER_PATH, F=USENET_MAILER_FLAGS, S=10, R=20,
U=news:news, _OPTINS(`USENET_MAILER_MAX', `M=', `, ')T=X-Usenet/X-Usenet/X-Unix, A=USENET_MAILER_ARGS $u
First, the MAILER() m4 command causes
initial support for the
usenet delivery agent to be included.
MAILER_DEFINITIONS section (see Section 19.6.40, MAILER-DEFINITIONS)
then introduces your new delivery agent definition.
Your new definition follows, and thus replaces, the original definition.
Create a new configuration file, and run grep(1) to check the result:
m4 our.mc > our.cf%
grep ^Musenet our.cfMusenet, P=/usr/lib/news/inews, F=rlsDFMmn, S=10, R=20, Musenet, P=/usr/lib/news/inews, F=rlsDFMmn, S=10, R=20, U=news:news,
From time to time you may need to create a brand-new delivery agent. To create a new delivery agent with the m4 system, first change to the cf/mailer directory. Copy an existing m4 file, one that is similar to your needs. Then edit that new file, and include it in your configuration file with
Note that the MAILER m4 command automatically prefixes the name
(_CF_DIR_ is described in Section 19.2.1)
and adds the suffix .m4, here forming
But be aware that creation of a new delivery agent is not for the
faint of heart. In addition to the delivery agent definition you
will also need to create brand new
and rule sets.