Tweaking Rulesets

For more complex configurations, you can define special rules. The macro LOCAL_RULE_3 introduces rules that are used in canonicalizing the names. Any modifications made here are reflected in the header.

A common use is to convert old UUCP addresses to SMTP addresses using the UUCPSMTP macro. For example:

	LOCAL_RULE_3
	UUCPSMTP(decvax,	decvax.dec.com)
	UUCPSMTP(research,	research.att.com)

will cause addresses of the form "decvax!user" and "research!user" to be converted to "user@decvax.dec.com" and "user@research.att.com" respectively.

This could also be used to look up hosts in a database map:

	LOCAL_RULE_3
	R$* < @ $+ > $*		$: $1 < @ $(hostmap $2 $) > $3

This map would be defined in the LOCAL_CONFIG portion, as shown below.

Similarly, LOCAL_RULE_0 can be used to introduce new parsing rules. For example, new rules are needed to parse hostnames that you accept via MX records. For example, you might have:

	LOCAL_RULE_0
	R$+ <@ host.dom.ain.>	$#uucp $@ cnmat $: $1 < @ host.dom.ain.>

You would use this if you had installed an MX record for cnmat.Berkeley.EDU pointing at this host; this rule catches the message and forwards it on using UUCP.

You can also tweak rulesets 1 and 2 using LOCAL_RULE_1 and LOCAL_RULE_2. These rulesets are normally empty.

A similar macro is LOCAL_CONFIG. This introduces lines added after the boilerplate option setting but before rulesets, and can be used to declare local database maps or whatever. For example:

	LOCAL_CONFIG
	Khostmap hash /etc/hostmap.db
	Kyplocal nis -m hosts.byname