[lug] routing

[Charles Morrison]

Hugh Brown wrote:

> I have 4 identical machines that will be part of a cluster eventually
> 
> Each has an onboard 10/100 nic and 3 10/100/1000 cards.
> 
> Each of the three gig cards is connected via crossover cable to one of
> the other three machines.  each machine has all three gig cards sharing
> the same ip address.  I was able to ssh to node2 from node1 yesterday. 
> I was trying to set up rsh/rlogin with rhosts for an oracle clustering
> product that depends on rsh (I know it is insecure...).  The rsh stuff
> from node1 to node2 wouldn't work at all.  I figured that the routing
> was probably all messed up and decided to tackle it today.  I rebooted
> node1 (they were all headless) after putting a keyboard, mouse and
> monitor on it.  Now, I couldn't even ping node2 let alone ssh to it. 
> All the gig cards showed that they were connecting at 1000 and full
> duplex.  I brought a laptop over and connected it to node1 via crossover
> cable to the onboard nic and that worked fine.  I connected the same
> crossover cable to one of the gig nics and the nic recognized that it
> was connected at 100 full duplex.  I pinged from the laptop and node1
> saw the arp requests and even responded a few times but none of the
> responses showed up on the laptop (via tcpdump).
> 

> I'm at a loss.



I can see why. I don't think you can get there the way you have it set 
up. Each gig card must either have it's own IP address OR they would 
have to be bonded and go to the same destination. I think your being 
able to do anything yesterday was a fluke.

If what you're trying to do is have one card dedicated to communicate 
soley to one other machine, use different class C networks for each 
destination and it's associated card and have them be members of one 
network. This way you don't have to muck with routing tables.


> 
> What's the next step?
> 
> Is there a way for a machine to ping itself from eth0 to eth1 (e.g. the
> onboard nic to a gig nic)?
> 
> The nodes right now are vanilla redhat with the updates applied.
> 
> Hugh
> 
> 
> 
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