While trying to get apache jserv to work, I kept getting errors about not being
able to resolve the hostname "localhost".
Thus I went browsing and found a few simple programs, none of which I could get
to work properly. Here is the one that I found most useful:
import java.net.*;
class HostCheck
{
public static void main(String argv[])
{
String hostname = argv[0];
try
{
System.out.println(InetAddress.getByName(hostname));
}
catch(Exception e)
{
System.out.println("Exception caught: " + e.toString());
}
}
}
And here are the results I had from running this program:
production:~/projects/inet>java HostCheck www.blackdown.org
www.blackdown.org/192.41.21.66
production:~/projects/inet>java HostCheck production
Exception caught: java.net.UnknownHostException: production
production:~/projects/inet>java HostCheck localhost
Exception caught: java.net.UnknownHostException: localhost
It seems like the java runtime is not trying to resolve the name via /etc/hosts,
but is instead going directly to the DNS!
I have included an attachment file which details my routing and name resolution
information.
Some other messages I found revealed that users were able to get this progam to
run properly:
/*
* Program: GetName.java
* @author: Qusay H. Mahmoud
* @version: Oct 29, 1996
*/
import java.net.*;
public class GetName {
public static void main(String argv[]) throws Exception {
InetAddress host = null;
host = InetAddress.getLocalHost();
System.out.println(host.getHostName());
}
}
However the result fails on my machine:
production:~/projects/inet>java GetName
java.net.UnknownHostException: production
at java.net.InetAddress.getAllByName0(InetAddress.java)
at java.net.InetAddress.getAllByName(InetAddress.java)
at java.net.InetAddress.getLocalHost(InetAddress.java)
at GetName.main(GetName.java:12)
The result here also seems like the java runtime is trying to resolve the name
with DNS instead of /etc/hosts.
Does anyone know the solution to this problem or know where to start looking?
--shawn
Note that some of the ip address has been taken out for security reasons.
AAA.AAA.AAA.AAA = The IP Address of this machine
BBB.BBB.BBB.BBB = The network address of this machine
CCC.CCC.CCC.CCC = The default gateway of this machine
Script started on Sat Oct 2 17:28:07 1999
production:~/projects/inet>cat /etc/host.conf
order hosts, bind
multi on
production:~/projects/inet>cat /etc/hosts
#
# hosts This file describes a number of hostname-to-address
# mappings for the TCP/IP subsystem. It is mostly
# used at boot time, when no name servers are running.
# On small systems, this file can be used instead of a
# "named" name server. Just add the names, addresses
# and any aliases to this file...
#
# By the way, Arnt Gulbrandsen <[EMAIL PROTECTED]> says that 127.0.0.1
# should NEVER be named with the name of the machine. It causes problems
# for some (stupid) programs, irc and reputedly talk. :^)
#
# The name of this host
AAA.AAA.AAA.AAA production
# For loopbacking.
127.0.0.1 localhost
production:~/projects/inet>route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
localhost * 255.255.255.255 UH 0 0 0 lo
BBB.BBB.BBB.BBB * 255.255.255.248 U 0 0 0 eth0
BBB.BBB.BBB.BBB * 255.255.255.248 U 0 0 0 eth0
default CCC.CCC.CCC.CCC 0.0.0.0 UG 1 0 0 eth0
production:~/projects/inet>hostname
production
production:~/projects/inet>ping localhost
PING localhost (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=0.2 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=255 time=0.0 ms
--- localhost ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.0/0.1/0.2 ms
production:~/projects/inet>ping production
PING production (209.198.147.146): 56 data bytes
64 bytes from AAA.AAA.AAA.AAA: icmp_seq=0 ttl=255 time=0.2 ms
64 bytes from AAA.AAA.AAA.AAA: icmp_seq=1 ttl=255 time=0.0 ms
--- production ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.0/0.1/0.2 ms
production:~/projects/inet>uname -a
Linux production 2.2.12 #10 SMP Wed Sep 29 18:48:37 CDT 1999 i686 unknown
production:~/projects/inet>^Dexit
Script done on Sat Oct 2 17:30:37 1999
