Fix port number in docs, and add to FAQ

site/faq.md

@@ -85,6 +85,12 @@ See [Using Fast Datapath](/site/using-weave/fastdp.md) for more information
 Yes, of course!  Weave allows you to run isolated networks and still allow open communications between individual containers from those isolated networks. You can find information on how to do this in [Application Isolation](/site/using-weave/application-isolation.md)
 
 
+**Q: Which ports does Weave Net use (e.g. if I am configuring a firewall) ?**
+
+You must permit traffic to flow through TCP 6783 and UDP 6783/6784,
+which are Weave’s control and data ports.
+
+
 **See Also**
 
  * [Troubleshooting Weave](/site/troublehooting.md)

site/using-weave.md

@@ -55,7 +55,7 @@ As noted above, the same steps are repeated for `$HOST2`. The only difference, b
 
 You can also peer with other hosts by specifying the IP address, and a `:port` by which `$HOST2` can reach `$HOST1`. 
 
->**Note:** If there is a firewall between `$HOST1` and `$HOST2`,  you must permit traffic to flow through TCP 6783 and UDP 6783/6798, which are Weave’s control and data ports.
+>**Note:** If there is a firewall between `$HOST1` and `$HOST2`,  you must permit traffic to flow through TCP 6783 and UDP 6783/6784, which are Weave’s control and data ports.
 
 There are a number of different ways that you can specify peers on a Weave network. You can launch Weave Net on `$HOST1` and then peer with `$HOST2`, or you can launch on `$HOST2` and peer with `$HOST1` or you can tell both hosts about each other at launch. The order in which peers are specified is not important. Weave Net automatically (re)connects to peers when they become available.