TCP/TCP Gateways

[mcvax!jungfrau!ceb@uunet.uu.net]

I have run this problem by the German Lispm users group, and the
comp.protocols.tcp-ip newsgroup on uucp, with no response.  I have
also asked my Symbolics rep.  Please help if you can.

We have a number of Symbolics 3670's running 7.1 with IP-TCP version
52.16.  These Symbolics hang on an Ethernet, which is interfaced
through several unix gateways to other Ethernets, which are in turn
interfaced to others, etc. etc.  TCP runs on all of these.

Problem: Even though I believe I have set up the namespaces right, I
cannot get the Symbolics to route to machines not directly on the
Ethernet to which it is connected.  I can try to establish a
connection from the other direction, and this gets routed to the
Symbolics, but since the Symbolics doesn't somehow find the  host
acceptable, the connection gets refused.

How I set it up:
1. There is a separate (namespace,site,network) triple for each
   individual physical network.  [This was my Symbolics' reps advice
   to me, and indeed there are variables in the IP-TCP code with names like
   "network-and-site-name" or some such which imply that whoever wrote
   it planned for it to be that way.  It didn't work any better when all
   the hosts were in one namespace, the way I set it up initially.]
2. Each gateway host has an entry for both networks, and the services 
    - gateway ip internet-gateway
    - gateway ip internet-gateway-prime
   This is the same service list configuration that a German university
   is using with an external gateway, but their configuration is somehow
   different, and all of a sudden they don't want to give out more details.
3. Hosts on the same network can establish connections with each other with
   no problem, so they have all the end user right services.

Yet when I try to connect to a host on the other network, I get an
error message stating that the connection service I am requesting is
not supported by the remote host, followed by a lists of the services
supported by the local and remote hosts (both of which contain the
requested service!).

Has anyone succeeded in getting a non--trivial network configuration
to work with the Symbolics software?  Even Symbolics?  The "ARPAnet"
interface software they deliver seems to be "hardwired" for a single
network of Symbolics on a Chaosnet interface to the big monolithic
ARPAnet via a Symbolics machine serving as a Chaosnet-to-TCP-net
gateway.  That is just not the case here.  I hacked it around to fit
our situation, but I seem to be missing the proper incantation.

What's the secret?  Tracing through the code, it seems that a new
network protocol is needed, (when I substitute the TCP/Chaos protocol
in, it does the routing ok, and then crashes because the streams don't
have the right properties), however certain TCP hackers (who only know
Unix) around here tell me this is nonsense --- that routing takes
place in the IP layer, and I should never see it.

What gives?

Charles Buckley				uucp: mcvax!ethz!ceb
					earn: BUCKLEY@CZHETH5A
                                        arpa: mcvax!ethz!ceb@uunet.uu.net
					      cb@sail.stanford.edu
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