Current bitcoin-master on testnet, `maxconnections=8` in the config file. Running in VM that doesn't have public IP and is not reachable from the Internet.

Wait until you have 8 peers.

```
telnet localhost 18333
```

It will result in:

```
Assertion failed: (nMaxInbound > 0), function AcceptConnection, file net.cpp, line 973.
```

First found in https://github.com/bitcoin/bitcoin/pull/8996, but can be reproduced on master.

if (HaveNameProxy()) {
            AddOneShot(seed.host);
        } else {
            std::vector<CNetAddr> vIPs;
            std::vector<CAddress> vAdd;
            ServiceFlags requiredServiceBits = nRelevantServices;
            if (LookupHost(GetDNSHost(seed, &requiredServiceBits).c_str(), vIPs, 0, true))
            {
                BOOST_FOREACH(const CNetAddr& ip, vIPs)