diff --git a/README.md b/README.md
index f2745d67..853a747d 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@ With the rise of governmental monitoring programs, Tox, a FOSS initiative, aims
 ## The Complex Stuff:
 ### UDP vs. TCP
 Tox must use UDP simply because [hole punching](http://en.wikipedia.org/wiki/UDP_hole_punching) with TCP is not as reliable.
+However, Tox does use [TCP relays](https://github.com/irungentoo/ProjectTox-Core/blob/master/docs/TCP_Network.txt) as a fallback if it encounters a firewall that prevents UDP hole punching.
 
 ### Connecting & Communicating
 Every peer is represented as a [byte string][String] (the public key [Tox ID] of the peer). By using torrent-style DHT, peers can find the IP of other peers by using their Tox ID. Once the IP is obtained, peers can initiate a [secure](https://github.com/irungentoo/ProjectTox-Core/wiki/Crypto) connection with each other. Once the connection is made, peers can exchange messages, send files, start video chats, etc. using encrypted communications.