Modified Bindlib for smail 3.1.28
=================================

Release numbers (look in RCS comments at top of files):-
	bindlib.h	1.4
	bindlib.c	1.5

What is it:-

  This code is a re-implementation of the smail 3.1.28 bindlib router
  which uses MX records to route mail.  It differs from the standard
  version in having additional functionality, mostly aimed at the UK
  mess of mail standards, as well as being vastly different in 
  implementation.

Major Features over and above standard bindlib:-

  + required - (domain) used for fire wall setups
  + mx_domains - list of domains which *must* have MX records
    for their mail hosts
  + rewrite_headers - changes nasty effects it has on headers
  + cname_limit - prevents DNS/cname loops
  + uk_greybook_relay - names a (PP?) mailer which handles mail
    that UK rules say should be sent by greybook/X400
  + uk_greybook_hosts* - attributes for file of contactable
    greybook hosts
  + uk_greybook_hosts_list - like file for limited hosts!
  + uk_suffix - list of domains which are treated in a "uk" like
    manner.

Who needs it:-

  Any UK academic site.  Any site wanting the earlier features.

How to install it:-
  + Replace (save a copy :-) ), bindlib.[ch] with these files.
  + Add the following 2 lines to the end of error.h
	#define ERR_176         176L            /* greybook hosts file lookup error */
	#define ERR_177         177L            /* BIND - CNAME loop */
  + make as usual (make a test version first).
  + modify config files - all the config bits are detailed in the top few pages
    of bindlib.c
  + go for it

Beta Test
  This is beta test software.  Please treat with care.  I have been running
  a substantially similar version at York for many months, as has Philip Hazel
  at Cambridge, but we will not have found all the problems.

  Please report problems to me 
	Nigel Metheringham <nigelm@ohm.york.ac.uk>
  Patches (context and/or unidiffs) are welcome.  Please keep the whitespace
  to be all spaces (no tabs) as this can cause problems applying patches!

Todo:-
  + Manual page requires updating again (not supplied this time!)
  + Modifications to some error messages.
  + Make sure that unecessary DNS lookups are not performed.

						[Nigel Metheringham - 19 Oct 93]