From: Eric Hodel <drbrain@...7.net>
Date: 2005-09-20T08:54:54+09:00
Subject: Re: nslookup/config question

On 19 Sep 2005, at 16:49, Eric Hodel wrote:

> On 19 Sep 2005, at 13:26, Frank Goodman wrote:
>
>
>> Apologies in advance if this is the wrong place to post,  
>> appreciate any
>> pointers to the right place if I've polluted the wrong thread
>>
>> Specifics:
>>   ruby 1.8.2 (2004-12-25) [i686-linux]
>>   Host: Linux gentoo 2.6.12
>>
>> My linux box does not run a nameserver, as it is a home machine  
>> that I use
>> for development. I connect to the internet through a Dlink router and
>> cable-modem.
>>
>> When I do a Socket/TCPSocket.gethostbyname call from within ruby, for
>> "unknown" hosts it returns an array that corresponds to my DynDNS  
>> domain name
>> with my "public IP address"
>>
>> When I run `nslookup` it returns:
>>
>> ** server can't find foo.foobar.frt: NXDOMAIN
>>
>> With the socket version it is more complicated for me to determine  
>> bad hosts
>> and I certainly can't do it in a portable way, so I'd like to set  
>> things up so
>> the Ruby.Socket code returns a proper error.
>>
>> I'm guessing this has something to do with my (improper)  
>> configuration of my
>> system or router. Any help would be appreciated
>>
>> I am curious why I would get different behaviours from the Ruby  
>> gethostbyname
>> and nsslookup which I would imagine should resolve down to a  
>> gethostbyname
>> call as well.
>>
>> Ideas?
>>
>
> I don't think this is a ruby issue...
>
> $ nslookup foo.foobar.frt
> Server:         192.168.1.15
> Address:        192.168.1.15#53
>
> ** server can't find foo.foobar.frt: NXDOMAIN
>
> $ ruby -rsocket -e 'Socket.gethostbyname("foo.foobar.frt")'
> -e:1:in `gethostbyname': getaddrinfo: hostname nor servname  
> provided, or not known (SocketError)
>         from -e:1
>
> Ruby uses the libc resolver to look up domain names.  (I forget if  
> nslookup uses libc or its own builtin resolver... host does under  
> OS X.)

... host uses its own builtin resolver under OS X ...

> Try also the pure-ruby DNS resolver:
>
> $ ruby -rresolv -e 'p Resolv.getaddress("foo.foobar.frt")'
> /usr/local/lib/ruby/1.8/resolv.rb:89:in `getaddress': no address  
> for foo.foobar.frt (Resolv::ResolvError)
>         from /usr/local/lib/ruby/1.8/resolv.rb:39:in `getaddress'
>         from -e:1
>
>
> -- 
> Eric Hodel - drbrain@segment7.net - http://segment7.net
> FEC2 57F1 D465 EB15 5D6E  7C11 332A 551C 796C 9F04
>
>

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E  7C11 332A 551C 796C 9F04