Domain Name System


Domain Name System (DNS) is a distributed database system for managing host names and their associated Internet Protocol (IP) addresses.

Using DNS means that people can use simple names, such as to locate a host, rather than using the IP address ( A single server might only be responsible for knowing the host names and IP addresses for a small subset of a zone, but DNS servers can work together to map all domain names to their IP addresses. DNS servers working together is what allows computers to communicate across the Internet.

For IBM® OS/400® Version 5 Release 1 (V5R1), DNS services are based on the industry-standard DNS implementation, known as Berkeley Internet Name Domain (BIND) version 8. Previous IBM OS/400 DNS services were based on BIND version 4.9.3. To use the new BIND version 8 DNS server, have i5/OS® option 31 (DNS) and option 33 (PASE) installed on your IBM System i™ model. If you do not have PASE installed, you can still run the same DNS server based on BIND version 4.9.3 that was available in previous releases. However, the migration to BIND 8 provides improved functions and incorporates better security for your DNS server.

This topic discusses new features based on BIND 8. If you are not using PASE to run DNS based on BIND 8, see the V4R5 DNS book for information regarding DNS based on BIND 4.9.3.