Programming Perl, 4th Edition

getnetent

getnetent
setnetent STAYOPEN
endnetent

These functions iterate through your /etc/networks file. The return value in list context is:

($name, $aliases, $addrtype, $net) = getnetent();

In scalar context, getnetent returns only the network name. The Net::netent module supports a by-name interface to this function. See getnetent(3).

The concept of network names seems rather quaint these days; most IP addresses are on unnamed (and unnameable) subnets.