hostname

[Rick Stevens]

On Thu, 2007-11-01 at 17:00 +0000, tony.chamberlain at lemko.com wrote:
>  Someone wants to use java and get a host name from an IP address.
> 
> I know how to do it lcoally through /etc/hosts BUT the host file does
> not
> 
> have names for every IP address reachable.
> 
>  
> 
> Someone found http://www.faqs.org/rfcs/rfc953.html which looks like
> you are supposed to be
> 
> able to use port 101 of a machine and connect to it and echo a command
> and it should respond.
> 
> It also says HNAME should give the host name so I tried (from
> 192.168.5.191)
> 
>       echo HNAME | nc -e cat 192.168.5.15 101 
> 
> which I would guess should return the host name for machine
> 192.168.5.15, but I got
> 
> no response and a return code of 1.  There is probably something I am
> overlooking.
> 
> Anyone know how to query this port?  (both machines are CentOS 4.5) 

I've seen very few systems that implement that server (the one on port
101).  The correct thing to do is to use a reverse DNS lookup such as
"dig -x 192.168.0.1" (assuming that the machine is registered in DNS).
This is reasonably easy to do in Java.  Look for functions such as
"gethostbyaddr".
> 
> 
> 
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- Rick Stevens, Principal Engineer             rstevens at internap.com -
- CDN Systems, Internap, Inc.                http://www.internap.com -
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-            The gene pool could use a little chlorine.              -
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