From: enterpoop.mit.edu!eru.mt.luth.se!lunic!sunic!mcsun!sun4nl!tuegate.tue.nl!eba!ebh!wjw@ucbvax.Berkeley.EDU  (Willem Jan Withagen)
Subject: Re: Apollo TCP woes
Organization: Eindhoven University of Technology, The Netherlands
Distribution: fj
Date: Fri, 18 Dec 1992 09:26:25 GMT
Return-Path: <apollo-list-errors@srvr1.engin.umich.edu>

In article <1992Dec17.002418.6709@ssigv.UUCP> gdonl@sunrise.ssi1.com (Don Lewis) writes:
=>Rlogin connections from a node on the token ring to HP 700 and Sun
=>nodes nodes on our ethernet using an Apollo as a TCP/IP router between
=>the networks are occasionally dropped.  It appears that the Apollo being
=>used as a router is sending an ICMP {NET,HOST} UNREACHABLE to to the token
=>ring only node, which then drops the connection.  We aren't real sure since
=>we don't have a way to sniff packets on the token ring.  We haven't yet
=>seen anything suspicious on the ethernet.  The router node shouldn't be
=>sending these packets, since it is directly attached to both networks.
=>The other node should not drop an existing connection upon the receipt of
=>an ICMP UNREACHABLE since this may be a transient condition.

We had/have so same type of problems in connecting to an SGI/IRIX system.
(Which also want to run -notrailers. :{ )

We've got one main ring, a gateway apollo to the backbone, and several thinnet stretches
which run from an apollo to a PC-router. The PC-router is also connected to the
backbone as backup gateway:

--------------------BACKBONE--------------------------------------------------------
	|                                            |              |
    +--------+   		                +--------+      +--------+
    | apollo |      				|   PC   |      | SUN    |
    |  gate  |				        |  gate  |      | 3/110  |
    +--------+         				+--------+      +--------+
      |    |                                      |
      |  +---+ 900/400s                           |
      |  |   +------------------------------------+-----------------------
      |  +---+         |                  |                ||||||||||||
      |    |         +---+ 9000/        +---+  SGI      +-----------------+
      .    .         |   |  400dl       |   |           |  PC's + PC-NFS  |
      .    .         +---+              +---+           +-----------------+
      .    .

Now the fun part is:
  -	the SUN can get to the SGI no materwhat.
  -	THE SGI refuses to recognise the HP9000's ever!!
  -     the 400s and 400dl talk perfect dds and tcp/ip                 
  -     the PC can use both HP9000's and the SGI (NFS,telnet,ftp,...)
  -	Everything can go through the Apollo-gate, except the SGI
  -	but the PC-router is always in a bad shape
                                                    
Now things improve a little when I switch off, the 400dl
But when we started running '/etc/tcpd -c -b -p0' did all the problems go away.

I'm to much of an TCP/IP illiterate to know what I've violated, but this
works. And our users (Mainly me :-) ) are much happier.
And now I can pull the plug on the Apollo-gate, and thing just get rerouted
through the PC-router. At a lower speed, but traffic doesn't stop :-)

	Willem Jan
Digital Information Systems Group, Room EH 10.35 
Eindhoven University of Technology   
P.O. 513                     		Tel: +31-40-473401,Fax: +31-40-448375
5600 MB Eindhoven            		The Netherlands
Newsgroups: fj.mail-lists.apollo