DNS

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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.