How can I test whether a computer is visible on the network in a Perl program?

The Net:ing module is probably the best way to do this - available from the CPAN if you don't already have it loaded.

Here's a module I use to test for web servers running on port 80 ... you can also test for icmp (or udp) rather than tcp visibility - icmp is the "normal" ping but has to be run with admin privelidge.

Code:

use Net::Ping; package seehost; # Wrapper around Ping. Wrapper can be amended as need be to tune ping params sub testhost {        $p = new Net::Ping("tcp");        $p->{port_num}=80;        @result = $p -> ping($_[0],2);        $result[0];        } 1;

Built into a program on our inhouse network, this allows us to check all our systems in a few seconds - it does involve a bit of forking (perhaps I should post this as a separate thread?) but we get results like:

Code:

Testing the network (port 80) ... ... ... ... 192.168.200.65 (wind) responded ... ... ... 192.168.200.134 (penguin) responded ... 192.168.200.144 (thursday) responded 192.168.200.145 (friday) responded 192.168.200.160 (mars) responded ... 192.168.200.176 (nan.wellho.co.uk) responded ... 192.168.200.188 (biriani) responded 192.168.200.189 (macdougall) responded 192.168.200.190 (pasanda) responded 192.168.200.193 (tea) responded ... 192.168.200.203 (saturn) responded ... 192.168.200.230 (panther) responded ... ... Testing completed Trainer's console connected via wireless Projection laptop connected via wireless Cable and backup ISDN internet connections both present

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