hostname

 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)

[Aaron Konstam]

On Thu, 2007-11-01 at 10:11 -0700, Rick Stevens wrote:
>  On Thu, 2007-11-01 at 17:00 +0000, tony.chamberlain(a)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".
>  >  
The host command also does this.
--
=======================================================================
E Pluribus Unix
=======================================================================
Aaron Konstam telephone: [phone] e-mail: akonstam(a)sbcglobal.net

[Rick Stevens]

On Thu, 2007-11-01 at 17:00 +0000, tony.chamberlain(a)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".
>  
>  
>  
>  -- 
>  fedora-list mailing list
>  fedora-list(a)redhat.com
>  To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
----------------------------------------------------------------------
- Rick Stevens, Principal Engineer             rstevens(a)internap.com -
- CDN Systems, Internap, Inc.                http://www.internap.com -
-                                                                    -
-            The gene pool could use a little chlorine.              -
----------------------------------------------------------------------