Programm welches Ports überwacht

[¬¬]

#!/usr/bin/perl

This is a simple script that scans a machine for reachable TCP ports.

usage : tcpscan <hostname> [maxtcp]

Apr 96 Rob J Meijer  [e-mail]

my  ($name,$aliases,$type,$len,$thataddr);
my  ($srv_name,$srv_aliases,$srv_port,$srv_proto);

$|=1;
$tghost=$ARGV[0];
if ($#ARGV>0) {
   $maxprt=$ARGV[1];
}
else {
   $maxprt=1023; #The well-known ports of 65535
}

if ($tghost eq "") {
  print "scans a machine for reachable TCP ports\n",
 "usage: tcpscan <hostname> [maxports to scan]\n";
 }
else {
  print "scanning $maxprt ports on $tghost\n";

$AF_INET=2;
$SOCK_STREAM=1;
$sockaddr='S n a4 x8';
($name,$aliases,$proto)=getprotobyname('tcp');
foreach $port (1 .. $maxprt)
{
 ($name,$aliases,$port)=getservbyname($port,'tcp')
   unless $port=~ /^\d+$/;;
  ($name,$aliases,$type,$len,$thisaddr)=gethostbyname($hostname);
 ($name,$aliases,$type,$len,$thataddr)=gethostbyname($tghost);
 $this=pack($sockaddr,$AF_INET,0,$thisaddr);
 $that=pack($sockaddr,$AF_INET,$port,$thataddr);
 if (!socket(S,$AF_INET,$SOCK_STREAM,$proto))
 {
  die $!;
 }
 if (!bind(S,$this))
 {
  die $!;
 }

if (connect(S,$that))
 {
   ($srv_name,$srv_aliases,$srv_port,$srv_proto)=getservbyport($port,'tcp');
   print "\r$port  $srv_name\n";
   close(S);
 }
 else
 {
  print "\r($port)";
 }
}
print "\r               \n";
}