List flag: check-addrs

If this flag is set, submissions and subscription requests (including
addresses added by "auto-subscribe") must appear to come from an
address that is reasonably formatted so that replies are likely to
reach the original subscriber.

If "auto-subscribe" is set on a list as well as "check-addrs", and a
submission arrives from an address for which the "check-addrs" test
fails, "auto-subscribe" is ignored for that submission.

The "check-addrs" test divides the address into a user part and a host
part, and will pass if and only if all of the following are true:

	- the user part and the host part both exist (e.g. not just a
	  userid; there must be an "@" or "%" in there someplace)
	- the host part does not end with a period
	- the host part contains only letters, numbers, hyphens and dots,
	  with no adjacent dots and no terminating dot (as per RFC1034
	  section 3.5)
	- the user part and the host part both contain 
	- the user part and the host part must not contain any non-printable
          characters
	- the user part must contain at least one alphanumeric character

NOTE: This flag is obsolete and will be removed in a near-future version
of listmanager.

See also: addrcheck auto-subscribe
