Newsgroups: vmsnet.networks.tcp-ip.multinet
Subject: Re: DECwindows over IP problem and an FDDI problem.
From: LPZ@LUDWIG.CTD.ORNL.GOV
Date: 10 SEP 92 19:57:49 GMT
Organization: The INFO-MULTINET Community
X-Gateway-Source-Info: INTERNET
X-Return-path: <info-multinet-relay@TGV.COM>
X-RFC822-From:    LPZ@LUDWIG.CTD.ORNL.GOV (Lawrence MacIntyre)
X-Vmsmail-To: SMTP%"R.E.Sonneveld%research.ptt.nl"

>We've two problems. Hope you can help us.
>
>1. The first problem is related to the opening of a DECwindows window
>   over TCP/IP on  a  Multinet  host.  We  get  the  following  error
>   message. I can't find it neither in the Multinet  manual,  nor  in
>   the DECwindows User Guide.
>
>> dectermport failed to find language, XOpenDisplay("") returned NULL
>> %DECW-F-CANT_OPEN_DISPL, Can't open display
>
>Anyone triggered?
        The only time I ever saw this was in an early DECnet/OSI field
        test.  From the context, I inferred that the transport wasn't
        loaded when DECwindows server was started, but this wasn't the
        case.  A later update solved the problem.  Perhaps you are
        starting DECwindows before Multinet is fully running.

>2. On our Multinet host we've both an ethernet and an FDDI interface.
>   The default route is via ethernet. Changing the default  route  to
>   FDDI gives me a lot of unreachable systems on the ehternet  behind
>   our cisco. Hope someone can tell me  how  to  make  the  FDDI  the
>   default route?
>
>   Another  problem is, that the fddi interface is not reachable from
>   other  systems.  However,  if  I first do a ping from the multinet
>   host  towards such a system, than that system (if it's on fddi) is
>   placed  in  the  ARP  table,  and  then  the  fddi  interface *is*
>   reachable  from  that  system.  This  trick  doesn't  work from an
>   ethernet  host,  because  the ethernet cisco interface is the only
>   (default)  route  in  the  ARP table. What should I do to make the
>   FDDI interface available towards any system on our LAN?

        This one gets me too.  The problem is bad code in your Cisco box.
        They are aware of it and promise a fix.  You probably have a
        bridge between your ethernet and your FDDI ring and your Cisco
        has both FDDI and ethernet interfaces.  The problem is that an
        ARP reply is seen by the router on both sides, and the ethernet
        (almost) always sees it last.  If you login to the Cisco and type
        SHOW ARP, you will see that your FDDI interface is seen on the
        ethernet side.  Interestingly, if an ethernet interface is seen
        on the FDDI side, it works...  Anyway, the workaround is to put a
        permanent ARP entry for your FDDI interfaces (all of them that
        you wish to be able to talk through the Cisco) in the router.
        There are many strange behaviors associated with this problem,
        and I don't wish to keep typing for the next two days, I will
        merely tell you that this workaround has proved 100% effective
        for us.
                                    Lawrence
                                        ~
        p.s.  I have used the words "router" and "Cisco" interchangeably
              in the above text.  Sorry for any confusion...
Newsgroups: vmsnet.networks.tcp-ip.multinet