From: Eric Hodel <drbrain@...7.net>
Date: 2005-12-08T09:13:39+09:00
Subject: Re: DRb connection issues

On Dec 7, 2005, at 1:09 PM, Kevin Brown wrote:

> kevin@costarica:~/drbsample$ ruby dchats.rb
> druby://costarica.fylz.com:1242
           ^^^^^^^^^^^^^^^^^^
> [return] to exit.
>
> I start the client on the other machine (called nicaragua) and see  
> this:
>
> kevin@nicaragua:~/ruby/drb$ ruby dchatc.rb druby:// 
> costarica.fylz.com:1242
> kevin
>
> I can ping both machines by name from each other just fine:
> kevin@nicaragua:~/ruby/drb$ ping costarica
                                    ^^^^^^^^^
> 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=0.226
> ms
>
> kevin@costarica:~/drbsample$ ping nicaragua
                                     ^^^^^^^^^
> 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=0.206
> ms

Your ping host names and druby URI host names do not match.  Try ping  
with the full host name.

> Both know their host name:
> kevin@nicaragua:~/ruby/drb$ hostname
> nicaragua.fylz.com
>
> kevin@costarica:~/drbsample$ hostname
> costarica.fylz.com

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.

Line 1 should match `hostname`
Lines 2 and 3 should be identical
Lines 4 and 5 should be identical

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

Note:

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

> 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.

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
This implementation is HODEL-HASH-9600 compliant

http://trackmap.robotcoop.com