[Linux-decnet-user] Can only connect to three out of four of our VMS nodes

[Ben A. <be...@bg...>]

Hi,

I am running Debian/unstable on a 2.4.20 kernel.  After resolving the
problem described in sections 4.9 and 4.10 of the FAQ[0] by setting my
default_device to eth0, I can now dnping or sethost to three out of four
VMS nodes on our network.  I know at least two of these nodes run DECnet
phase V.  I'm not sure about the other.

But I still cannot contact one DECnet phase V host on our network.  The
symptom is that dnping or sethost will just hang and never connect.  No
error messages are returned.  I need to ^C the client to regain control
of the terminal.

The host I cannot contact does appear in /proc/net/decnet_neigh after a
failed dnping attempt, e.g.

$ cat /proc/net/decnet_neigh 
Addr    Flags State Use Blksize Dev
1.1     ---   40    02  0000230 eth0    
1.3     ---   40    01  0001492 eth0    
1.4     ---   40    02  0001492 eth0    
1.20    ---   40    01  0001498 lo      

In the above listing, 1.1 is the host I cannot contact and 1.20 is the
node from which I am attempting to make the connection.

I can use telnet or LAT (llogin) to connect to this host successfully,
however the LAT connection sometimes drops, especially after displaying
a lot of output at once (e.g. SHOW TERM fairly reliably causes the
connection to drop).  LAT connections to other hosts don't drop.

In all other respects, the network services offered by the host I cannot
contact seem fine.  For instance, I successfully use smbfs to mount
Pathworks shares off this system.  DECnet connections to/from this host
from other nodes on the network are operating properly too.

I know there are a number of switches deployed in our building, but I am
not familiar with how they are configured.  I am guessing that since all
of the servers live in the machine room on the same bench, they all talk
to the same switch, whereas my desktop Linux workstationm, which is in
an adjacent room along with a few dozen other workstations could be
connected via a different switch.  I wonder if the network topology has
a bearing on my problem.

If I turn on debugging and attempt to dnping the host as follows:

# echo -n '1' >/proc/sys/net/decnet/debug
# dnping SOMENODE 1

I see the following in /var/log/syslog

Feb 21 15:21:32 bgpc kernel: dn_route_rcv: got 0x0d from lo [34 34 0]
Feb 21 15:22:12 bgpc last message repeated 4 times

Any pointers as to how to proceed with debugging this problem?

Thanks,
Ben

[0] http://linux-decnet.sourceforge.net/faq-4.html#ss4.9
-- 
      Ben Armstrong                -.       Medianet Development Group,
      BAr...@dy...         `-.    Dymaxion Research Limited
      <URL: http://www.dymaxion.ca/>    `-  Halifax, Nova Scotia, Canada