Merge pull request #710 from pi-hole/tweak/FORCE_LOCAL_RESOLVER

Internal resolver tweaks

src/resolve.c

@@ -39,11 +39,12 @@ static char *resolveHostname(const char *addr)
  return hostname;
  }
 
- // Back up first ns record in _res and ...
- struct in_addr nsbck;
- nsbck = _res.nsaddr_list[0].sin_addr;
+ // Force last available (MAXNS-1) server used for lookups to 127.0.0.1 (FTL itself)
+ struct in_addr nsbck = { 0 };
+ // Back up corresponding ns record in _res and ...
+ nsbck = _res.nsaddr_list[MAXNS-1].sin_addr;
  // ... force FTL resolver to 127.0.0.1
- inet_pton(AF_INET, "127.0.0.1", &_res.nsaddr_list[0].sin_addr);
+ inet_pton(AF_INET, "127.0.0.1", &_res.nsaddr_list[MAXNS-1].sin_addr);
 
  // Test if we want to resolve an IPv6 address
  if(strstr(addr,":") != NULL)
@@ -80,8 +81,8 @@ static char *resolveHostname(const char *addr)
  strtolower(hostname);
  }
 
- // Restore first ns record in _res
- _res.nsaddr_list[0].sin_addr = nsbck;
+ // Restore ns record in _res
+ _res.nsaddr_list[MAXNS-1].sin_addr = nsbck;
 
  // Return result
  return hostname;