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

!CVerifyDB().VerifyDB(
                                chainparams, &chainstate->CoinsDB(),
                                args.GetArg("-checklevel", DEFAULT_CHECKLEVEL),
                                args.GetArg("-checkblocks", DEFAULT_CHECKBLOCKS))) {
                            strLoadError = _("Corrupted block database detected");
                            failed_verification = true;
                            break;
                        }
                    }
                }
            } catch (const std::exception& e) {
                LogPrintf("%s\n", e.what());
                strLoadError = _("Error opening block database");
                failed_verification = true;
                break;
            }
            if (!failed_verification) {
                fLoaded = true;
                LogPrintf(" block index %15dms\n", GetTimeMillis() - load_block_index_start_time);
            }
        } while(false);
        if (!fLoaded && !ShutdownRequested()) {
            
            if (!fReset) {
                bool fRet = uiInterface.ThreadSafeQuestion(
                    strLoadError + Untranslated(".\n\n") + _("Do you want to rebuild the block database now?"),
                    strLoadError.original + ".\nPlease restart with -reindex or -reindex-chainstate to recover.",
                    "", CClientUIInterface::MSG_ERROR | CClientUIInterface::BTN_ABORT);
                if (fRet) {
                    fReindex = true;