1 files changed, 8 insertions, 3 deletions
diff --git a/systrace/catapult/telemetry/third_party/web-page-replay/dnsproxy.py b/systrace/catapult/telemetry/third_party/web-page-replay/dnsproxy.py
index a913d84..171b996 100644
--- a/systrace/catapult/telemetry/third_party/web-page-replay/dnsproxy.py
+++ b/systrace/catapult/telemetry/third_party/web-page-replay/dnsproxy.py
@@ -34,11 +34,16 @@ class DnsProxyException(Exception):
   pass
 
 
+DEFAULT_DNS_PORT = 53
+
+
 class RealDnsLookup(object):
-  def __init__(self, name_servers):
-    if '127.0.0.1' in name_servers:
+  def __init__(self, name_servers, dns_forwarding, proxy_host, proxy_port):
+    if (proxy_host in name_servers and proxy_port == DEFAULT_DNS_PORT and
+        dns_forwarding):
       raise DnsProxyException(
-          'Invalid nameserver: 127.0.0.1 (causes an infinte loop)')
+          'Invalid nameserver: %s (causes an infinte loop)'.format(
+              proxy_host))
     self.resolver = resolver.get_default_resolver()
     self.resolver.nameservers = name_servers
     self.dns_cache_lock = threading.Lock()