DNS Deployments with ClearOS
This guide covers best practices of deploying name services within an infrastructure when using ClearOS. It covers single site deployments, deployments with AD, and multi-site deployments of ClearOS. This guide is intended to be used by admins with a good understanding of DNS.
How DNS works on ClearOS
There are two main elements to DNS resolution on ClearOS:
NOTE: Usage of 3rd party DNS servers like BIND are not addressed by this deployment guide but the concepts presented should be beneficial.
The behavior of ClearOS for name server lookups is determined by the /etc/nsswitch.conf file. In this file, the default behavior is defined as:
hosts: files dns
The settings listed here should typically be left alone to whatever mode is configured by Webconfig. The defualt behavior is for hosts to be looked up in files (ie. /etc/hosts) and then queried through the settings in dns (ie. /etc/resolv.conf) if the files does not resolve the DNS.
ClearOS comes with a caching DNS server called DNSMasq. This service handles both DNS services and DHCP services.