From: Kevin Brown <blargity@...>
Date: 2005-12-09T00:51:43+09:00
Subject: Re: DRb connection issues

Thanks for the reply!

On Wednesday 07 December 2005 18:13, Eric Hodel wrote:
>[...]
> Your ping host names and druby URI host names do not match.  Try ping
> with the full host name.

kevin@nicaragua:~$ ping costarica.fylz.com
PING costarica.fylz.com (192.168.2.105) 56(84) bytes of data.
64 bytes from costarica.fylz.com (192.168.2.105): icmp_seq=1 ttl=64 time=0.317 
ms

kevin@costarica:~$ ping nicaragua.fylz.com
PING nicaragua.fylz.com (192.168.2.102) 56(84) bytes of data.
64 bytes from nicaragua.fylz.com (192.168.2.102): icmp_seq=1 ttl=64 time=0.183 
ms

> On each machine try:
> $ ruby -rsocket -e 'p Socket.gethostname'
> "kaa.coop.robotcoop.com
> $ ruby -rsocket -e 'p Socket.gethostbyname("kaa.coop.robotcoop.com")'
> ["kaa.coop.robotcoop.com", [], 2, "\300\250\001F"]
> $ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\001F")'
> ["kaa.coop.robotcoop.com", [], 2, "\300\250\001F"]
> $ ruby -rsocket -e 'p Socket.gethostbyname("rur-1.coop.robotcoop.com")'
> ["rur-1.coop.robotcoop.com", [], 2, "\300\250\001\v"]
> $ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\001\v")'
> ["rur-1.coop.robotcoop.com", [], 2, "\300\250\001\v"]
>
> Where 'kaa.coop.robotcoop.com' is the local machine and
> 'rur-1.coop.robotcoop.com' is the remote machine.

== Server ==
kevin@costarica:~$ ruby -rsocket -e 'p Socket.gethostname'
"costarica.fylz.com"

kevin@costarica:~$ ruby -rsocket -e 'p 
Socket.gethostbyname("costarica.fylz.com")'
["costarica.fylz.com", ["localhost.localdomain", "localhost", "costarica", 
"costarica"], 2, "\177\000\000\001", "\300\250\002i"]

kevin@costarica:~$ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\002i")'
["costarica.fylz.com", ["costarica"], 2, "\300\250\002i"]

kevin@costarica:~$ ruby -rsocket -e 'p 
Socket.gethostbyname("nicaragua.fylz.com")'
["nicaragua.fylz.com", ["nicaragua"], 2, "\300\250\002f"]

kevin@costarica:~$ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\002f")'
["nicaragua.fylz.com", ["nicaragua"], 2, "\300\250\002f"]

== Client ==
kevin@nicaragua:~$ ruby -rsocket -e 'p Socket.gethostname'
"nicaragua.fylz.com"

kevin@nicaragua:~$ ruby -rsocket -e 'p 
Socket.gethostbyname("nicaragua.fylz.com")'
["nicaragua.fylz.com", ["localhost.localdomain", "localhost", "nicaragua", 
"nicaragua"], 2, "\177\000\000\001", "\300\250\002f"]

kevin@nicaragua:~$ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\002f")'
["nicaragua.fylz.com", ["nicaragua"], 2, "\300\250\002f"]

kevin@nicaragua:~$  ruby -rsocket -e 'p 
Socket.gethostbyname("costarica.fylz.com")'
["costarica.fylz.com", ["costarica"], 2, "\300\250\002i"]

kevin@nicaragua:~$ ruby -rsocket -e 'p Socket.gethostbyaddr("\300\250\002i")'
["costarica.fylz.com", ["costarica"], 2, "\300\250\002i"]


> Line 1 should match `hostname`

It does.

> Lines 2 and 3 should be identical

They're obviously not.  So what do I change to get them to be?

> Lines 4 and 5 should be identical

They are.

> In lines 2 through 5 the last item should not match:
> "\177\000\000\001"

It's not the last item, but is there.

And just to make sure that it's still happening, I tried running the dchats 
and dchatc programs again and got the same error.

> Note:
>
> "\177\000\000\001".scan(/./).map { |c| c[0] }.join '.'
> => "127.0.0.1"

Makes sense.

> > And here are the contents of both of their /etc/hosts files:
> >
> > kevin@nicaragua:~/ruby/drb$ cat /etc/hosts
>
> I would set up DNS instead of relying on hosts files, I've found
> hosts files fragile.