It's surprising that using a non-standard listening port will cause peers to actively avoid connecting to you, is it sensible to add this to the help message and the warnings on startup if people have changed the default? I can't find this behavior mentioned anywhere except for the comments in net.cpp. 

```
// do not allow non-default ports, unless after 50 invalid addresses selected already
if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50)
continue;
```

https://github.com/bitcoin/bitcoin/blob/master/src/net.cpp#L1369

int nRelevant = 0;
                    {
                        LOCK(cs_vNodes);
                        for (const CNode* pnode : vNodes) {
                            if (pnode->fSuccessfullyConnected && pnode->IsOutboundOrBlockRelayConn()) ++nRelevant;
                        }
                    }
                    if (nRelevant >= 2) {
                        if (found > 0) {
                            LogPrintf("%d addresses found from DNS seeds\n", found);
                            LogPrintf("P2P peers available. Finished DNS seeding.\n");
                        } else {
                            LogPrintf("P2P peers available. Skipped DNS seeding.\n");
                        }
                        return;
                    }
                }
            }
        }
        if (interruptNet) return;
        
        if (!fNetworkActive) {
            LogPrintf("Waiting for network to be reactivated before querying DNS seeds.\n");
            do {
                if (!interruptNet.sleep_for(std::chrono::seconds{1})) return;
            } while (!fNetworkActive);
        }
        LogPrintf("Loading addresses from DNS seed %s\n", seed);
        if (HaveNameProxy()) {
            AddAddrFetch(seed);