Why the '+' sign in the packet data? I tried this:

$sock->print("n 8.8.8.8.\n");
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And it works fine. Windows 7 x64, Strawberry 5.18.1:

VinsWorldcom@C:\Users\VinsWorldcom\tmp> cat test.pl
use strict;
use warnings;

use Data::Dumper;
use IO::Socket;

my %whois_servers = (
  "RIPE"=>"whois.ripe.net",
  "APNIC"=>"whois.apnic.net",
  "KRNIC"=>"whois.krnic.net",
  "LACNIC"=>"whois.lacnic.net",
  "ARIN"=>"whois.arin.net",
  "AFRINIC"=>"whois.afrinic.net",
);

my $sock = IO::Socket::INET->new(
  PeerAddr=>$whois_servers{ARIN},
  PeerPort=>'43',
  Timeout=>'60',
);

$sock->print("n 8.8.8.8\n");
my @ret = <$sock>;
@ret = grep {length($_)} map { s/\n//; $_ } @ret;

print Dumper(\@ret);

VinsWorldcom@C:\Users\VinsWorldcom\tmp> test.pl
$VAR1 = [
          '#',
          '# ARIN WHOIS data and services are subject to the Terms of 
+Use',
          '# available at: https://www.arin.net/whois_tou.html',
          '#',
          '#',
          '# The following results may also be obtained via:',
          '# http://whois.arin.net/rest/nets;q=8.8.8.8?showDetails=tru
+e&showARIN=false&ext=netref2',
          '#',
          'Level 3 Communications, Inc. LVLT-ORG-8-8 (NET-8-0-0-0-1) 8
+.0.0.0 - 8.255.255.255',
          'Google Incorporated LVLT-GOOGL-1-8-8-8 (NET-8-8-8-0-1) 8.8.
+8.0 - 8.8.8.255',
          '#',
          '# ARIN WHOIS data and services are subject to the Terms of 
+Use',
          '# available at: https://www.arin.net/whois_tou.html',
          '#'
        ];
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