I can't seem to find a public daytime server

See Set Your Computer Clock Via the Internet and NIST Internet Time Servers.

Your next challenge is to write a DAYTIME server, and configure launchd on your own system to run it on demand.

The following modification of your code will parse the NIST standard DAYTIME format.

use strict;
use warnings;
#use 5.010;

use IO::Socket;

#my $host = 'localhost';
#my $host = 'time.nist.gov';
#my $host = 'nist1-sj.ustiming.org';
my $host = 'time-nw.nist.gov';      # pester microsoft
my $port = 'daytime(13)';

my $sock = IO::Socket::INET->new(
    Proto       => 'tcp',
    PeerHost    => $host,
    PeerPort    => $port,
) or die "cannot connect: $!";

while (<$sock>) {
    s/^[[:space:]]+//;
    s/[[:space:]]+\z//s;
    next if /^$/;

    # NIST Daytime Protocol format
    # http://tf.nist.gov/service/its.htm
    # JJJJJ YR-MO-DA HH:MM:SS TT L H msADV UTC(NIST) OTM
    if ($_ =~ /^(\d+)\s+(\d{2})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2}):(\d{
+2})\s+(\d{2})\s+(\d)\s+(\d)\s+([0-9\.]+)\s+UTC\(NIST\)\s+(.)/)
    {
        my ($mjd, $yr, $mo, $da) = ($1,$2,$3,$4);
        my ($hour, $min, $sec, $dst, $lsec) = ($5,$6,$7,$8,$9);
        my ($health, $msADV, $otm) = ($10,$11,$12);
        print "NIST: $yr-$mo-$da $hour:$min:$sec\n";
    }
    else
    {
        print "$_\n";
    }
}
[download]

Before asking my question here, I visited all the links in your post while looking for public daytime servers, but I couldn't get any host to work. My program just hung. Now things seem to be working.

All I was trying to do was retrieve a line of text from a remote host to see if I could get a simple networking program to work.

Thanks.

mahbe should have tried HTTP instead, your browser conn seems to work :)

#!/usr/bin/perl
use warnings;
use strict;
use IO::Socket;

# su to root first, unless sudo is setup correctly for the commands 

my $datecommand='date -s';  #'set system time' command

my $request ="HEAD / HTTP/1.0\r\nHost: \r\nUser-Agent:zzzdate\r\nPragm
+a: no-cache\r\n\r\n";

my $socket = IO::Socket::INET->new    (
    Proto        => 'tcp',
    PeerAddr    => 'www.google.com',
    PeerPort    => 80
) or die "Can't connect $!\n";

# Send HEAD requests
print "$request\n";
print $socket $request;

while (defined (my $res = <$socket>) ) {
    print "$res\n";
    if ( $res =~ /Date: / ) {
        # Like-> Date: Wed, 22 Oct 2008 18:30:46 GMT
        $res =~ s/Date: //;
        #print "$res\n";
        print "Setting time... ", `$datecommand \"$res\"`;
    }
}

close $socket;

#zero out adjtime if time keeps getting thrown off unexpectedly
#open (TH,"> /etc/adjtime") or die "$!\n"
#close TH;
[download]

It's my computer, and I have full admin privileges, so I would like to welcome my script with open arms.

So you are connecting to your own machine and asking for information from daytime. In that case, you need to be running a daytime service. 'Connection refused' means any of several things, including that there is nothing listening on the port that you connected to (or, per AM's comment, that you are being blocked or ...). OS X does not provide such a service by default. IOW, you also need to find code for a daytime service (or write your own) that listens on port 13.

You are at your home, and ask Bob for the time. There is no response, and a light bulb goes off in your head saying "Connection refused". Being at home, you have full admin privileges, but that means nothing to Bob. Is bob even in your house?