doc: warn that incoming conns are unlikely when not using default ports

Github-Pull: #20668
Rebased-From: 010eed3ce03cf4fc622a48f40fc4d589383f7a44

1 files changed, 5 insertions, 1 deletions

diff --git a/src/net.cpp b/src/net.cpp
index cf987b6995..1fd913eb64 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2050,7 +2050,11 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
                 continue;
             }
 
-            // do not allow non-default ports, unless after 50 invalid addresses selected already
+            // Do not allow non-default ports, unless after 50 invalid
+            // addresses selected already. This is to prevent malicious peers
+            // from advertising themselves as a service on another host and
+            // port, causing a DoS attack as nodes around the network attempt
+            // to connect to it fruitlessly.
             if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50)
                 continue;