Hello all,
again the list prooved to be quick and helpful.
Special Thanks to : Thomas Blinn, Tom Webster, William J. Bochnik (William,
that was the second or third time you helped me out!), and Serguei
Patchkovskii.
---------------------------- Problem Description
--------------------------------
System COnfiguration:
2 x DEC Alpha 1000 4/266, hardware completely identical, Digital Unix 4.0 D
Each has two Ethernetcards, 1 pci (tu1) and 1 ISA (tu0).
Both machines are connected to our local intranet using tu1 and everything
is working fine.
PROBLEM:
Now i wanted to connect both machines via tu0, assigning an ip address
using ifconfig and connecting the cards using a 5 feet coax wire with T -
connectors and terminal resistors (so it should work i guess). (REASON:
Both machines are syncing their data using rsync and thus swapping a lot of
data. I dont want to use the intranet for that cause it slows the traffic
there considerably down).
I used lan_config to switch the tu0īs to bnc mode and ifconfig to set the
ip adresses (xxx.yyy.105.80 and xxx.yyy.105.90), netmasks (255.255.255.0)
and broadcast adresses (xxx.yyy.105.255).
Interfaces are up and running.
Now added the entry "-host xxx.yyy.105.80 xxx.yyy.105.90" and vice versa in
the /etc/routes, the lan_config and ifconfig lines in /etc/inet.local and
the entry for tu0 in /etc/rc.config, rebooted - and the machine was stuck.
I could telnet it from another machine, but the CDE didnt start, and the
samba and httpd services were unreachable (except from the subnet
xxx.yyy.105.nnn - from where (strange enough) obviously everything worked,
i.e. all machines in subnet 105 COULD use httpd, smbd and so on while
machines from other subnets could NOT). Connecting via telnet to the
machine trying to ping another server FROM the machine resulted in an error.
---------------------------- SOLUTION -------------------------------------
The problem had three levels:
a) Hardware configuration
The card used for tu0 ( Digital EtherWORKS Turbo EISA ) defaults to TP
rather than to bnc mode; i used lan_config -i tu0 -m bnc to fix that (entry
in /etc/inet.local created)
b) Adress space used:
It is not possible (i should have guessed that!) to use both cards on the
same adress space, even though not both are connected to the local ethernet
backbone. So I assigned "internal" IPs to the tu0īs (192.128.xxx.yyy) using
netconfig. SPECIAL THANKS here to Tom Webster, who spent a lot of lines in
explaining to me the basic rules of correct adressing!
c) Routing:
It is not necessary to add the internal adresses of the tu0īs to
/etc/routes - this confuses the routing. Deleting the entry from
/etc/routes and leaving the routing to the internal TPC/IP stack who does
it simply depending on the ifconfig . SPECIAL THANKS here to William Bochnik.
----------------------------------------------------------------------------
----------------------------------------
YS, CW
------------------------------------------
Dr. Christian Wessely
christian.wessely_at_kfunigraz.ac.at
url: www-theol.kfunigraz.ac.at
PGP Public Keys deposed there
Received on Fri Jan 19 2001 - 11:24:22 NZDT