A zone file is stored on a name server and provides information about one or more domain names. Each zone file contains a list of DNS records with mappings between domain names and IP addresses. These records define the IP address of a domain name, the reverse lookup of an IP to other domains, and contain DNS and mail server information.
Because zone files are plain text files, they can be edited quickly and easily. However, this also means that if unauthorized users gain access to zone files, the files can be easily modified. This could cause websites to not respond, or worse yet, redirect to the wrong Web server. For this reason, it is important to keep the zone files on a highly secured server and always have a recent backup of zone files on another machine.