DNS

Domain Name Servers are how clients are able to get automatic hostname-to-IP-address resolution. Since all servers and clients on our network must be set up with static IP addresses, the settings for DNS are very important for getting communication to function properly. Currently, einstein and roentgen are set up as DNS servers.

Server Configuration

The related RPMs installed on einstein are:

bind

includes DNS server, named

bind-utils

utilities for querying DNS servers about host information

bind-libs

libraries used by the bind server and utils package

caching-nameserver

config files for a simple caching nameserver

(more info)

Client Configuration

The important config files are /etc/host.conf, /etc/hosts, and /etc/resolv.conf. The information in these files can also be safely editied via the graphical system-config-network program.

/etc/host.conf

Defines the oder in which the client will search for hostname resolution. This typically contains only order hosts,bind, which means to first check the "hosts" file, then try bind to a DNS server and get the answer there.

/etc/hosts

Contains a list of IP addresses and their associated hostnames. This typically constains info for localhost, einstein, and the machine's own hostname(s).

/etc/resolv.conf

Contains the subnet to search and a list of DNS servers' IP addresses. This typically contains "farm.physics.unh.edu" along with einstein and roentgen's IP addresses.