From 73c133c91dbd4ed8dba4496ce764fee90906fa62 Mon Sep 17 00:00:00 2001
From: 3D-I <480857+3D-I@users.noreply.github.com>
Date: Tue, 2 Jun 2020 12:14:16 +0200
Subject: [PATCH] [ticket/16508] Fix WhoIs lookup

PHPBB3-16508
---
 phpBB/includes/functions_user.php | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index d39dbed5ff..a44b92dd8d 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1470,8 +1470,11 @@ function user_ipwhois($ip)
 
 	$ipwhois = '';
 
-	// Limit the query to all possible flags (whois.arin.net)
-	$ip = 'z ' . $ip;
+	if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6))
+	{
+		// Limit the query to all possible flags (whois.arin.net)
+		$ip = 'z ' . $ip;
+	}
 
 	if (($fsk = @fsockopen($whois_host, 43)))
 	{