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

#if !defined(MSG_DONTWAIT)
#define MSG_DONTWAIT 0
#endif
enum BindFlags {
    BF_NONE         = 0,
    BF_EXPLICIT     = (1U << 0),
    BF_REPORT_ERROR = (1U << 1),
    /**
     * Do not call AddLocal() for our special addresses, e.g., for incoming
     * Tor connections, to prevent gossiping them over the network.
     */
    BF_DONT_ADVERTISE = (1U << 2),
};
static const uint64_t SELECT_TIMEOUT_MILLISECONDS = 50;
const std::string NET_MESSAGE_COMMAND_OTHER = "*other*";
static const uint64_t RANDOMIZER_ID_NETGROUP = 0x6c0edd8036ef4036ULL; 
static const uint64_t RANDOMIZER_ID_LOCALHOSTNONCE = 0xd93e69e2bbfa5735ULL; 
static const uint64_t RANDOMIZER_ID_ADDRCACHE = 0x1cf2e4ddd306dda9ULL; 
bool fDiscover = true;
bool fListen = true;
RecursiveMutex cs_mapLocalHost;
std::map<CNetAddr, LocalServiceInfo> mapLocalHost GUARDED_BY(cs_mapLocalHost);
static bool vfLimited[NET_MAX] GUARDED_BY(cs_mapLocalHost) = {};
std::string strSubVersion;
void CConnman::AddAddrFetch(const std::string& strDest)
{
    LOCK(m_addr_fetches_mutex);
    m_addr_fetches.push_back(strDest);
}
uint16_t GetListenPort()