DNS

BIND

ISC LogoIs open source software that implements the Domain Name System (DNS) protocols for the Internet. It is a reference implementation of those protocols, but it is also production-grade software, suitable for use in high-volume and high-reliability applications. BIND is by far the most widely used DNS software on the Internet, providing a robust and stable platform on top of which organizations can build distributed computing systems with the knowledge that those systems are fully compliant with published DNS standards.

Microsoft

Microsoft LogoMicrosoft Windows server operating systems can run the DNS Server service. This is a monolithic DNS server that provides many types of DNS service, including caching, Dynamic DNS update, zone transfer, and DNS notification. DNS notification implements a push mechanism for notifying a select set of secondary servers for a zone when it is updated.

Like various other DNS servers, Microsoft’s DNS server supports different database back ends. Microsoft’s DNS server supports two such back ends. DNS data can be stored either in master files (also known as zone files) or in the Active Directory database itself. In the latter case, since Active Directory (rather than the DNS server) handles the actual replication of the database across multiple machines, the database can be modified on any server (“multiple-master replication”), and the addition or removal of a zone will be immediately propagated to all other DNS servers within the appropriate Active Directory “replication scope”. (Contrast this with BIND, where when such changes are made, the list of zones, in the /etc/named.conf file, has to be explicitly updated on each individual server.)

Prior to Windows Server 2003 and Microsoft Windows 2000 Service Pack 3, the most common problem encountered with Microsoft’s DNS server was cache pollution. Although Microsoft’s DNS Server had a mechanism for properly dealing with cache pollution, the mechanism was turned off by default. In 2004, a common problem involved the feature of the Windows Server 2003 version of Microsoft’s DNS server to use EDNS0, which a large number of firewalls could not cope with.