From 2c6666cb349dc14950ff8ae328334f2f7c07aadb Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Thu, 1 Sep 2016 03:34:22 +0000
Subject: [PATCH] Avoid crash if Npcap is not present when doing reverse DNS.

---
 nmap_dns.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nmap_dns.cc b/nmap_dns.cc
index d075abf63..634abfd6f 100644
--- a/nmap_dns.cc
+++ b/nmap_dns.cc
@@ -965,7 +965,8 @@ void win32_read_registry() {
 
     for (i=0; sz = sizeof(buf), RegEnumKeyEx(hKey, i, buf, &sz, NULL, NULL, NULL, NULL) != ERROR_NO_MORE_ITEMS; i++) {
 
-      if (!interface_is_known_by_guid(buf)) {
+      // If we don't have pcap, interface_is_known_by_guid will crash. Just use any servers we can find.
+      if (o.have_pcap && !interface_is_known_by_guid(buf)) {
         if (o.debugging > 1)
           log_write(LOG_PLAIN, "Interface %s is not known; ignoring its nameservers.\n", buf);
         continue;