Node.js server only listening on ipv6 - node.js

Question

I am running a node.js server on port 5403. I can telent to the private ip on this port but cannot telnet to the public ip on the same port.
I assume the cause of this is because node.js is only listening on ipv6. This is the result of
netstat -tpln
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
PID/Program name
tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN
-
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
-
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
-
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN
-
tcp6 0 0 :::5611 :::* LISTEN
25715/node
tcp6 0 0 :::22 :::* LISTEN
-
tcp6 0 0 ::1:631 :::* LISTEN
-
tcp6 0 0 :::5403 :::* LISTEN
25709/node
How do I make the node server listen on ipv4

Answer 1

You need to specify an IPV4 address when you call the listen(), I had the same issue with the http module. If I use this:
var http = require('http');
var server = http.createServer(function(request, response) {
...
});
server.listen(13882, function() { });
It only listen on IPV6, as you can see from netstat output:
$ netstat -lntp
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp6 0 0 :::13882 :::* LISTEN
However, if I specify an IPV4 address like this:
var http = require('http');
var server = http.createServer(function(request, response) {
...
});
server.listen(13882, "0.0.0.0", function() { });
netstat will report the server as listening on IPV4:
$ netstat -lntp
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0 0.0.0.0:13882 0 0.0.0.0:13882 LISTEN
I'm using Ubuntu 16.04 and npm 5.3.0.
HTH