On Thu, 2007-11-01 at 10:11 -0700, Rick Stevens wrote: > On Thu, 2007-11-01 at 17:00 +0000, tony.chamberlain@xxxxxxxxx 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: (210) 656-0355 e-mail: akonstam@xxxxxxxxxxxxx
