Clarify inbound and outbound port requirements
@@ -178,11 +178,14 @@ defaults write com.apple.CrashReporter DialogType none
### Network Ports and Data Usage
-By default, Zebra uses the following inbound TCP listener ports:
+Zebra uses the following inbound and outbound TCP ports:
- 8233 on Mainnet
- 18233 on Testnet
+Outbound connections are required to sync, inbound connections are optional.
+Zebra also needs access to the Zcash DNS seeders, via the OS DNS resolver (usually port 53).
+
Zebra needs some peers which have a round-trip latency of 2 seconds or less.
If this is a problem for you, please
[open a ticket.](https://github.com/ZcashFoundation/zebra/issues/new/choose)
