remote cups printing + 'firewall'

[Alexander Volovics <awol home nl>]

I have a small home network connected to the internet via a router
with NAT and a printer connected to my main pc.

For reasons that are not relevant here I use aliases (eth0:1) to
define my home network (172.16.x.x numbers).  I connect to the router
via dhcp (192.168.x.x numbers). As I only communicate between the pc's
with ssh and ftp over ssh this is adequate for my needs.
I use the RH "medium security" 'firewall' to get some extra 'protection'.

In principle I can print files from my laptop, say, by ftping the
file to my main pc and then printing it from there.

But now with Shrike installed on all pc's I wanted to use cups/sharing
to print directly from the 'remote' pc.
Just like I had used it with cups on RH-8.0. But then I had a dedicated
pc as firewall/router with 2 ethernet cards (one for the 'internet' and
one for the 'home network'). And I experienced no problems configuring
cups through the browser (or by hand) and adding the few necessary
browse and address items to cupsd.conf by hand.

Now with Shrike I decided to use the 'redhat-config-printer' tool
to configure cups printing/sharing (as advised).

This works perfectly for my main pc. I can print without problems.

But I can't print from a remote pc. 

I see two possible problems:

1) redhat-config-printer does not seem to produce a correct cupsd.conf
   file. These are the last lines of cupsd.conf:
   </Location>
   Browsing On
   BrowseProtocols cups
   BrowseOrder Deny,Allow
   BrowseAllow from @LOCAL
   Listen 127.0.0.1:631
   
   Some other posts on this list have also mentioned this. Can cups
   function in a local network by only listening on 127.0.0.1:631 or
   should the adress of the pc with the printer be included here (like
   I had it when in the situation described above last year).

   Editing cupsd.conf by hand has no effect.

2) the "medium security firewall".
   I added an ACCEPT rule to RH-Lokkit-0-50-INPUT to enable packets
   for udp port 631 but printing remotely then still does not work.
   So I suspect that the main problem is 1).

Can somebody give me some hints on how to solve this?
I suspect that both problems will have to be adressed.

Alexander