thanks everybody, problem solved! as paul j. schindler pointed out tMacPerl cannot do ICMP echo. but tcp and udp work. in my case this is enough. use Net::Ping; $host = "foo.bar.foo.bar"; $p = Net::Ping->new("udp", 1); print "$host$i is alive.\n" if $p->ping($host.$i); $p->close(); $p = Net::Ping->new("tcp", 1); print "$host$i is alive.\n" if $p->ping($host.$i); $p->close(); the above script does the job. thanks everybody jochen hagenstroem ===== jochen hagenstroem [EMAIL PROTECTED] __________________________________________________ Do You Yahoo!? Yahoo! Auctions - Buy the things you want at great prices! http://auctions.yahoo.com/