Looking at the code, MultiHomed only works when an addresses is specified in PeerAddr/PeerHost (as opposed to using connect like you did), and it only works when a domain name is specified (as opposed to an IP address like you did). Try:

#!/usr/bin/perl

use IO::Socket::INET;

my $sock = IO::Socket::INET->new( 
    Proto      => 'tcp',
    PeerAddr   => 'alistapart.com',
    PeerPort   => 'http',
    MultiHomed => 1,
    Blocking   => 1,
    Type       => SOCK_STREAM,
)
   or die("Unable to connect: $!\n");
  

$sock->send(qq{GET / HTTP/1.0\r\n\r\n});
$sock->recv($buffer, 1024);
print $buffer . "\n";
[download]