Network adapter failing when using node.js - node.js

Question

I'm having this super bizarre problem at work; I've made two small node.js programs that interact with each other via HTTP get and post requests. Program B monitors some text files and sends a post request to Program A anytime the files change (once a minute). After acknowledging that request, Program A then sends a post request to program B, which then writes another set of text files.
The computer that hosts program B, at some (unpredictable) point in the day, just stops getting proper network connection—we'd be unable to use the browser, unable to remote desktop, and the node program also can't communicate, logging with ECONNRESET errors. It can, however, ping other machines in the network and on the internet. We thought there was a problem with the network card so we actually switched the machine which runs Program B and we still have the same problem.
We've noticed this only happens when Node.js is running, and is actively sending https requests to and from program A. A restart is the only solution we've found that sets things back to normal.
Our next idea was to install Wireshark and see what's up. The first thing that we noticed is this on the 'info' field:
3000→53550 [RST, ACK] Seq=2 Ack=1 Win=0 Len=0
It happens once every minute, and seems to be from the machine hosting Program A. Is this normal behavior? (Wireshark highlights it in red) Network communication is still normal at this point.
Eventually, it zero's out a TCP window and then things get worse:
We started to see duplicate acknowledgements and lots of retransmissions being sent:
and then finally the TCP window being full, and then reset:
Network communication fails at this point (except being able to ping).
I'm totally lost. I don't know whether this is a problem with my programming, or with node's implementation of network tools, or whether it's a driver / hardware issue, or a kernel issue.
We're running Windows 7 on both machines. Node 4.4.1
Any help or advice on what this could be would be really appreciated.
EDIT
Here's the some code snippets regarding the sending and receiving of information in Program B (I'm using Express.js) .
Receiving:
app.post('/eton_call', function (req, res){
logger.info("POST REQUEST: eton_call") //using winston.js to log things
reqCalls_writer.write_file(req.body); //writes the text file in a certain format
res.sendStatus(201);
})
app.post('/USERPRUN_call', function (req, res){
logger.info("POST REQUEST: userprun_call")
userPrun_writer.write_file(req.body);
res.sendStatus(201);
})
Sending: (they all use this prototyped function. The argument, snapshot, is some JSON)
Eton_file_sync.prototype.send_snapshot = function(snapshot) {
logger.info('sending snapshot');
var post_options = {
host: config.fex_server.host,
port: config.fex_server.port,
path: this.post_uri,
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': snapshot.length
}
};
var post_req = http.request(post_options, function(res) {
logger.info("STATUS: " + res.statusCode);
res.setEncoding('utf8');
res.on('data', function (chunk) {
logger.info('Response: ' + chunk);
});
});
post_req.on('error', function(e){
logger.error('Snapshot not sent. Please ensure connectivity to fex-server.js. This snapshot will be lost. Error Message: ' + e.message);
})
post_req.write(snapshot);
post_req.end();
}
Here's the code for writing files
Eton_asc_writer.prototype.write_file = function (data_arr){
logger.info("writing file");
var buffer_data = '';
data_arr.forEach(function (data_element, index, array){
for (prop in data_element){
_.find(this, function(template_element){//finds the template_element with the correct descriptions
return template_element.description == prop; //^
}).datum = data_element[prop];//copies over datum to template element
}
//finds the first then second then third.. nth field.
for (var field_order = 1; field_order < this.length; field_order++){
var current_field = _.find(this, function(template_element){
return template_element.field_order == field_order;
});
if (!current_field.datum && (current_field.datum != 0)){
current_field.datum = "";
}
var required_padding_amount = current_field.required_length - current_field.datum.toString().length;
assert(required_padding_amount >= 0, "invalid length on " + current_field.description);
//assert(current_field.type == typeof current_field.datum, "datum types don't match");
for (var padding = ''; padding.length < required_padding_amount;)
padding += ' ';
if (current_field.type == "string"){
current_field.padded_datum = current_field.datum + padding + ';';
}
else {
current_field.padded_datum = padding + current_field.datum + ';';
}
buffer_data += current_field.padded_datum;
}
buffer_data += '\r\n';//buffer newline
}, this.template_in_use);
//console.log(buffer_data);
write_buffer = new Buffer(buffer_data, 'utf8');
var file = fs.createWriteStream(this.filename);
file.write(write_buffer);
file.end();
}
For Program A, the only post requests that would be happening at the time come from this: (req_calls is an array of objects that share the same key/value pairs)
function exportReqCalls(req_calls){
if (req_calls.length == 0){
return;
}
exported_req_calls = JSON.stringify(req_calls);
var post_options = {
host: config.eton_agent.host,
port: config.eton_agent.port,
path: '/eton_call',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': exported_req_calls.length
}
};
var post_req = http.request(post_options, function(res) {
logger.info("STATUS: " + res.statusCode);
res.setEncoding('utf8');
res.on('data', function (chunk) {
//console.log('Response: ' + chunk);
});
});
post_req.on('error', function(e){
logger.error('ReqCall not sent. Please ensure connectivity to eton-agent.js. Error Message: ' + e.message);
});
post_req.write(exported_req_calls);
post_req.end();
}