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

{
    const std::string URL_SOURCE_CODE = "<https:github.com/bitcoin/bitcoin>";
    return CopyrightHolders(strprintf(_("Copyright (C) %i-%i").translated, 2009, COPYRIGHT_YEAR) + " ") + "\n" +
           "\n" +
           strprintf(_("Please contribute if you find %s useful. "
                       "Visit %s for further information about the software.").translated,
               PACKAGE_NAME, "<" PACKAGE_URL ">") +
           "\n" +
           strprintf(_("The source code is available from %s.").translated,
               URL_SOURCE_CODE) +
           "\n" +
           "\n" +
           _("This is experimental software.").translated + "\n" +
           strprintf(_("Distributed under the MIT software license, see the accompanying file %s or %s").translated, "COPYING", "<https:opensource.org/licenses/MIT>") +
           "\n";
}
static bool fHaveGenesis = false;
static Mutex g_genesis_wait_mutex;
static std::condition_variable g_genesis_wait_cv;
static void BlockNotifyGenesisWait(const CBlockIndex* pBlockIndex)