From dfecb88bd32aeaaa0828cc8680fd244b4cd629e4 Mon Sep 17 00:00:00 2001
From: marius <mmillea@ucdavis.edu>
Date: Wed, 26 Jul 2017 16:14:32 +0200
Subject: [PATCH] skip SFS check for obviously private IP addresses

---
 html/inc/email.inc | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/html/inc/email.inc b/html/inc/email.inc
index cdc5551361..a66425bdcf 100644
--- a/html/inc/email.inc
+++ b/html/inc/email.inc
@@ -93,8 +93,13 @@ For further information and assistance with ".PROJECT.", visit
 //
 function is_valid_email_addr($addr) {
     if (defined("USE_STOPFORUMSPAM") && USE_STOPFORUMSPAM && array_key_exists('REMOTE_ADDR', $_SERVER)) {
-        $ip_addr = $_SERVER['REMOTE_ADDR'];
-        $x = @file_get_contents("https://www.stopforumspam.com/api?ip=".$ip_addr."&email=".$addr);
+        $ip = $_SERVER['REMOTE_ADDR'];
+        // For obviously private IPs check just the email against SFS, otherwise check both IP and email
+        if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
+            $x = @file_get_contents("https://www.stopforumspam.com/api?ip=".$ip."&email=".$addr);
+        } else {
+            $x = @file_get_contents("https://www.stopforumspam.com/api?email=".$addr);
+        }
         if (substr_count($x, '<appears>yes</appears>')) {
             return false;
         }