# initialize your IO::Socket etc...
$SIG{ALRM} = sub { # code here to do something interesting 
                   # if your program isn't getting                      
                   # connections
                  }
my $minutes_to_wait = 5; # wait five minutes
my $alarm_seconds = $minutes_to_wait * 60;

alarm $alarm_seconds; # set the first alarm

while($server->recv($msg,$MAX_LEN) {
     # if we're here we got something
     # do some interesting stuff with the message
     
     #reset the alarm
     alarm $alarm_seconds;
}