I'm trying to send a DHCP DISCOVER message in accordance with the WPAD procedure given in Wikipedia and an old IETF draft. Following hints in the POD for Net::DHCP::Packet I have the following code:
use IO::Select;
use IO::Socket::INET;
use Net::DHCP::Constants;
use Net::DHCP::Packet;

my $socket = IO::Socket::INET->new(Proto => 'udp',
                                   Broadcast => 1,
                                   PeerPort  => '67',
                                   LocalPort => '4111',
                                   PeerAddr  => '255.255.255.255')
  or die ($@);

# create and send DHCP Packet
my $disc = Net::DHCP::Packet->new(
              xid => int(rand(0xFFFFFFFF)),
              Flags => 0x8000, # ask for broadcast answer
              DHO_DHCP_MESSAGE_TYPE() => DHCPDISCOVER())
    or die "Can't create DHCP discover packet: $!";

$socket->send($disc->serialize())
    or die "Can't send DHCP discover packet: $!";

my @ready = IO::Select->new($socket)->can_read(5);
if (@ready) {
  my $newmsg;
  $socket->recv($newmsg, 1024)
      or die "Can't recv DHCP discover packet: $!";
  my $packet = Net::DHCP::Packet->new($newmsg);
  # site-local option 252 "auto-proxy-config"
  my $wpad = $packet->getOptionValue(252);

[download]
On my home Mac OS X machines and work Windows XP machine, there is no answer to the discover packet: @ready is always empty after 5 seconds. Without the select and if statements, the recv hangs interminably.

For those into tcpdump output, here are one case and another.

Suggestions will be much appreciated, even if they just suggest a more appropriate forum on which to ask for help.

Thanks,
cmac

In reply to No reply to DHCP DISCOVER by cmac

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