Hi, I had to make a proxy server for a CS class. It uses perl and IO::Sockets. Here is my code. Hopefully it will be useful since it is implements both server and client code (the nature of a proxy server). If you are doing this for a class assignment yourself, please only use the code for reference. Otherwise have fun with it. I'm not that good of a perl programmer so all of the experts I'm sure will find flaws with it :-)

#!/usr/bin/perl -w

#################################
#    Jaz Server Proxy
#################################
#  Joe Jaisnski
#  Networking
#  Due: Oct 5 2004
#################################

$|=1;                      # flush buffer
use strict;                # enable strict mode to require var declara
+tion
use IO::Socket;            # use the IO::Sockets library

my $server_port = 7788;    # define the port that the proxy will run o
+n
my ($server);              # declare the server variable 

# establish the server socket 
my $socket_server = IO::Socket::INET->new( Listen => 5, LocalPort => $
+server_port, 
                                           Reuse => 1, Proto => 'tcp' 
+) 
  or die "cannot connect to port $server_port: $!";

while ($server = $socket_server->accept())  # loop while the file hand
+le is true (infinate loop)
  {
    my ($response_all, $content_length) = ("", 1000);  # declare some 
+vars
    my (@request_headers, @response_all);              # declare some 
+vars
    local $/ = "\015\012";                             # set the loop 
+break string 
    while (<$server>)                                  # while the soc
+ket is being accessed
      { 
    chomp;                                           # remove the newl
+ine at the end of each line
    last if $_ eq '';                                # break loop if i
+nput is empty
    push(@request_headers, $_ . "\n");               # push the input 
+onto an array
      }

    my ($host, $port) = $request_headers[1] =~ m/^Host:\s*([\w\d\.\-]+
+):?(\d*)/mi; # parse host and port
    my ($path) = $request_headers[0] =~ m#^GET (.+) HTTP/1.[01]# ;    
+             # parse out path
    # replace micorsoft.com with sourceforge.com if the host contains 
+MS or is empty
    if (($host =~ "microsoft.com") or ($host eq "")) { $host = "www.so
+urceforge.net"; $path = "/";} 
    if (!defined($port) or ($port eq '')) { $port = "80"; }       # ch
+eck to see if port is defined
    $request_headers[0] = "GET $path HTTP/1.1\n";                 # se
+tup replacement GET header
    $request_headers[1] = "Host: $host:$port\n";                  # se
+tup replacement Host: header

    # establish the client socket with newly determined host
    my $socket_client = IO::Socket::INET->new( PeerAddr => $host, 
                                               PeerPort => $port, Prot
+o => 'tcp') 
      or die "cannot connect to port $port at $host: $!";
    print $socket_client join('', @request_headers) . "\n";       # pr
+int headers to the socket

    my $client;                         # define scalar        
    while($client = <$socket_client>)   # read in retrieved content fr
+om the client socket 
      { print $server $client; }        # print the content to the bro
+wser

    $socket_client->close;              # close the connection
    $server->close;                     # close the connection

    ($host, $port, $path) = (undef, undef, undef);   # undefine the ho
+st port and path vars
  }
[download]