	Some hints at using  tcp-wrapper  with ZMailer


		Short:


/etc/hosts.allow:

  smtp-receiver : ALL : allow
  mailq : small-list : allow



		Long:

SMTPSERVER and SCHEDULER programs use tcp-wrapper to check which systems
are allowed to connect to the  SMTP  and  MAILQ  ports.

A bug(?) in autoconfiguration scripts present since times immemorial
caused that  tcpd.h  header file was not found automagically until
system version 2.99.51-patch1.  (Presuming it resides at /usr/include/ )

With that header, and related library ( -lwrap ) available, system does
enable tcp-wrapper a bit sneakily, and you *MUST* supply these explicite
lines into the  /etc/hosts.allow  (or where-ever it is in your system):

	smtp-receiver : ALL : allow
	mailq : small-list : allow

The "small-list" at "mailq" means listing just a few machines from
which you allow mailq to be queried at all.

Make sure these entries are before any wild-card "reject all" entries.

In the long run I will probably remove the wrapper test at SMTPSERVER,
because that program has other more powerfull machinery in place for
access control.


/Matti Aarnio - 17Aug1999
