Ping by Hostname

[sputniks]

Two linux (Redhat) computers are connected to an ordinary DSL router which runs DHCP service.
A router dynamically assigns 192.168.1.64 IP address to the first computer (hostname DENVER). And another machine (hostname DALLAS) is assigned 192.168.1.65.
The router's settings (site accessed via 192.168.1.1) shows both of those computers listed with their corresponding hostnames and IP addresses:

Connection Type: Ethernet
PC Name: DALLAS
IP Address: 192.168.1.64
MAC Address: 00:19:d1:9f:8d:52

Connection Type: Ethernet
PC Name: DENVER
IP Address: 192.168.1.65
MAC Address: 00:1b:63:ac:45:df



I can ping both machines using their corresponding IP addresses: "ping 192.168.1.64" and "ping 192.168.1.65". That works great.
The problem occurs when I try to ping them using their hostnames instead of their ip addresses. They even don't respond to PING command if I ping the machine with its own name!
I went ahead and "hard coded" (typed) the combination of host names and their ip addresses into the each computer's /etc/hosts configuration files:

192.168.1.64 DENVER.mynetwork DALLAS
192.168.1.65 DALLAS.mynetwork DENVER

To my surprise that fixed one computer. But only one computer.... another is still not reachable by hostname.
I forgot to mention that both computers running a very basic fresh all-by- default Redhat Linux install... meaning no dns servers or dhcp servers or other additional servers or services were installed yet.... Should I stop using DSL Router's DHCP server? Should I instead install Linux's DHCP server on one of the computers and run DHCP server on a computer?
Thanks in advance for any suggestions!

[sputniks]

Spent several hours searching the forum on this subject.
Looks like it is quite common problem.
Many people suggest to tweak /etc/resolv.conf file... but how?

[Lazydog]

Post the output from the following from both machine:

hosts
resolv.conf
host.conf

[sputniks]

/etc/hosts

computer with a hostname DALLAS:
=======================================
127.0.0.1 localhost.localdomain localhost
192.168.1.64 DALLAS.twosdomain DALLAS
192.168.1.65 DENVER.twosdomain DENVER

computer with a hostname DENVER:
=======================================
127.0.0.1 localhost.localdomain localhost
192.168.1.64 DALLAS.twosdomain DALLAS
192.168.1.65 DENVER.twosdomain DENVER

[sputniks]

etc/resolv.conf

DALLAS:
=============================
; generated by /sbin/dhclient-script
search twosdomain
nameserver 192.168.1.1
nameserver 68.238.64.12

DENVER:
=============================
; generated by /sbin/dhclient-script
search twosdomain
nameserver 192.168.1.1
nameserver 68.238.64.12

[sputniks]

/etc/sysconfig/network

DALLAS
==========================
HOSTNAME=DALLAS
NETWORKING=yes
NISDOMAIN=twosdomain


DENVER
==========================
NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=DENVER
NISDOMAIN=twosdomain

[rcgreen]

Run the /sbin/ifconfig command on each one and verify that
they still have the same addresses. It is possible to change on reboot.
To make sure they are always the same, you can, with most routers,
enter the router and reserve those addresses so the same computer
always gets the same address. Also make sure there isn't a typo
in /etc/hosts on one of them.

[sputniks]

# ifconfig

DALLAS:
=============================

eth0 Link encap:Ethernet HWaddr 00:191:9F:8D:52
inet addr:192.168.1.64 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::219:d1ff:fe9f:8d52/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3613 errors:0 dropped:0 overruns:0 frame:0
TX packets:4104 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:2753468 (2.6 MiB) TX bytes:670510 (654.7 KiB)
Memory:93100000-93120000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:1392 errors:0 dropped:0 overruns:0 frame:0
TX packets:1392 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:3675712 (3.5 MiB) TX bytes:3675712 (3.5 MiB)

[sputniks]

# ifconfig

DENVER:
=============================

eth0 Link encap:Ethernet HWaddr 00:C0:9F:37:12:9F
inet addr:192.168.1.65 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::2c0:9fff:fe37:129f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:154 errors:0 dropped:0 overruns:0 frame:0
TX packets:106 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:16495 (16.1 KiB) TX bytes:11144 (10.8 KiB)
Interrupt:22 Base address:0x800

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:6857 errors:0 dropped:0 overruns:0 frame:0
TX packets:6857 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:6111868 (5.8 MiB) TX bytes:6111868 (5.8 MiB)

[sputniks]

#route

I have no idea why ROUTE command's output is slightly different on these machines (mismatched output lines are highlighted with red colors)


DALLAS:
=============================

#route

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use face
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
169.254.0.0 * 255.255.0.0 U 0 0 0 eth0
default dslmodem.domain 0.0.0.0 UG 0 0 0 eth0


DENVER:
=============================
#route

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 0 0 0 eth0
default dslmodem.domain 0.0.0.0 UG 0 0 0 eth0