$_ = "permit ip 10.11.1.0  0.0.0.255 192.168.100.0 0.0.0.255";

while (/(?:host){0}\s+(\d+\.\d+\.\d+\.\d+)\s+(\d+\.\d+\.\d+\.\d+)/g){
    say "$1 $2";
}
__END__
10.11.1.0 0.0.0.255
192.168.100.0 0.0.0.255