Resolvconf

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In Linux and related computer operating systems, the resolvconf program keeps track of system information about the currently available nameservers. It should not be confused with the configuration file resolv.conf, which unfortunately has a nearly identical name.

Before a computer can connect to an external network resource (say, for example, a web server), it must have a means of converting any alpha-numeric names (e.g. wikipedia.org) into numeric network addresses (e.g. 66.230.200.10). (The Internet uses these structured numeric IP addresses as network addresses.)

The configuration file resolv.conf normally contains information about the the nameservers to be used by the system. However, when multiple programs need to dynamically modify the resolv.conf configuration file they can step on each other and the file can become out-out-sync. The resolvconf program addresses this problem. It acts as an intermediary between programs that supply nameserver information (e.g. dhcp clients) and programs that use nameserver information (e.g. resolver).

When resolvconf is properly installed, the resolv.conf configuration file at /etc/resolv.conf is replaced by a symbolic link to /etc/resolvconf/run/resolv.conf and the resolver instead uses the dynamically generated resolver configuration file at /etc/resolvconf/run/resolv.conf.

The resolvconf program is only necessary when a system has multiple programs that need to dynamically modify the nameserver information. In a simple system where the nameservers do not change often or are only changed by one program, the resolv.conf configuration file is adequate.