From my understanding, UDP is for simple messaging and they are not gauranteed to make it thru, like TCP is. So if your UDP server is hit with 1000's of messages at the same time, you might want to switch to TCP(with IO::Select) OR have multiple servers listening to lighten the possible simultaneous load.

Anyways, this is from the Cookbook Chapter 17 

#server
#!/usr/bin/perl -w
# udpqotd - UDP message server
use strict;
use IO::Socket;

my($sock, $newmsg, $hishost, $MAXLEN, $PORTNO);

$MAXLEN = 1024;
$PORTNO = 5151;

$sock = IO::Socket::INET->new(
           LocalPort => $PORTNO, 
       Proto => 'udp') or die "socket: $@";
       
print "Awaiting UDP messages on port $PORTNO\n";

while ($sock->recv($newmsg, $MAXLEN)) {
    my($port, $ipaddr) = sockaddr_in($sock->peername);
    $hishost = gethostbyaddr($ipaddr, AF_INET);
    print "Client $hishost said $newmsg\n";
    $sock->send("CONFIRMED: $newmsg ");
} 
die "recv: $!";

# You can't use the telnet program to talk to this server. You 
# have to use a dedicated client.

[download]
#client
#!/usr/bin/perl -w
# udpmsg - send a message to the udpquotd server

use IO::Socket;
use strict;

my($sock, $msg, $port, $ipaddr, $hishost, 
   $MAXLEN, $PORTNO, $TIMEOUT);

$MAXLEN  = 1024;
$PORTNO  = 5151;
$TIMEOUT = 5;

$sock = IO::Socket::INET->new(Proto     => 'udp',
                              PeerPort  => $PORTNO,
                              PeerAddr  => 'localhost')
    or die "Creating socket: $!\n";

$msg = 'testmessage'.time;

$sock->send($msg) or die "send: $!";

eval {
    local $SIG{ALRM} = sub { die "alarm time out" };
    alarm $TIMEOUT;
    $sock->recv($msg, $MAXLEN)      or die "recv: $!";
    alarm 0;
    1;  # return value from eval on normalcy
} or die "recv from localhost timed out after $TIMEOUT seconds.\n";

print "Server $hishost responded $msg\n";

# This time when we create the socket, we supply a peer host and 
# port at the start, allowing us to omit that information in the send.

# We've added an alarm timeout in case the server isn't responsive, 
# or maybe not even alive. Because recv is a blocking system call that
+ 
# may not return, we wrap it in the standard eval block construct 
# for timing out a blocking operation.

[download]
I'm not really a human, but I play one on earth. Cogito ergo sum a bum

In reply to Re: UDP Listener / Server by zentara
in thread UDP Listener / Server by webfreakin

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.