If you are on linux, or unix-style os, type 'ifconfig' , and read "man ifconfig"

For example, if you are root or have sudo priviledges for ifconfig:

open DH, "/sbin/ifconfig 'eth0'  | " or die "Could not run ifconfig";
    my $data = join "", <DH>; 
    close DH; 
    close DH;
print "$data
[download]

You can also set properties with ifconfig, as shown in the man page, or google searches.But you will almost certainly need to be root, with all the permissions in the deep network layers.