Client network socket disconnected before secure TLS connection was established

[Scott Kapelewski]

Hi,

I ran into an error where sometimes when running a server, it fails to secure a socket connection. Here's the stack trace:

{ Error: Client network socket disconnected before secure TLS connection was established
at TLSSocket.onConnectEnd (_tls_wrap.js:1088:19)
at Object.onceWrapper (events.js:277:13)
at TLSSocket.emit (events.js:194:15)
at endReadableNT (_stream_readable.js:1103:12)
at process._tickCallback (internal/process/next_tick.js:63:19)
code: 'ECONNRESET',
path: undefined,
host: null,
port: null,
localAddress: undefined }

Killing and starting the server over again fixes it (does not re-occur), but it happens in about 1 in 3 runs, and happens for every request. This is the trace on the server side:

Server[80]: 3 | Using HandlerTunnelChain
Server[80]: 3 | Connecting to upstream proxy...
Server[80]: 3 | Target socket assigned
Server[80]: 3 | Connected to upstream proxy
Server[80]: 3 | Target socket ended
Server[80]: 3 | Target socket closed
Server[80]: 3 | Source socket ended
Server[80]: 3 | Closing handler
Connection 3 closed
{ srcTxBytes: 203,
srcRxBytes: 139,
trgTxBytes: 143,
trgRxBytes: 205 }

Here's the request I'm making (which goes to an upstream proxy provider):

`
const userAgent = new UserAgent();
const userAgentString = userAgent.toString();
var agent = new HttpsProxyAgent(proxy_url);

request(
{
url: "https://example.com",
agent: agent,
method: 'get',
gzip: true,
headers: {
'User-Agent': userAgentString,
}
},
function(err, res, body) {
console.log(err)
}
)
`

[Jan Čurn]

What upstream proxy are you using, perhaps it disconnects too early? It would be great if you could provide the full code to reproduce this problem.

[Scott Kapelewski]

Thanks for the response, I'm using Smartproxy as the upstream provider. I haven't been able to pinpoint the exact conditions to replicate it, but there are two scenarios from startup of proxy-chain - it either works completely or this error occurs on every request. I'll continue running and monitoring to provide a better idea of what's going on - but right now it seems like if a socket disconnects upstream in an abnormal way, all subsequent connections do so.

[Jan Čurn]

This could also be explained by the upstream proxy being in some broken state. It's really hard to say without a working reproduction. BTW we're using the proxy-chain package on production to handle millions of HTTPS connection, and don't experience this issue...