How to use app.listen(port, host) with public hostname? - node.js

Question

Can I put public domain name as host argument in app.listen(port, host)?
I know my ip, and I have 3 domain names on this ip. domain1.com, domain2.com all on same ip. Now, I'm using switch in app.get('/') to routing request of different domain names. However, I'm wondering is there a way to route host when setting up app.listen.
I found the entry of app.listen([port[, host[, backlog]]][, callback]) is really vague on expressjs website. There's nothing about the "host" argument. I know it can be set to localhost or 127.0.0.1. But my code failed when I put public domain name in it.
Can anybody explain how the host argument works in app.listen? Thank you.
var express = require('express');
var app = express();
app.get('/', function(req, res) {res.send("hello")});
app.listen(3000, "my.domain");
Error code:
Error: listen EADDRNOTAVAIL: address not available myip:3000
at Server.setupListenHandle [as _listen2] (net.js:1281:19)
at listenInCluster (net.js:1346:12)
at GetAddrInfoReqWrap.doListen [as callback] (net.js:1485:7)
at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:65:10)
Emitted 'error' event on Server instance at:
at emitErrorNT (net.js:1325:8)
at processTicksAndRejections (internal/process/task_queues.js:80:21) {
code: 'EADDRNOTAVAIL',
errno: 'EADDRNOTAVAIL',
syscall: 'listen',
address: 'myip',
port: 3000
}
The server can't run.

Answer 1

Try to start server with hostname 0.0.0.0 and get access from other network points by your IP (check by ifconfig).

Answer 2

Find out the public ip of your public domain, then put it in the app.listen.
Example if your public ip is 1.2.3.4:
app.listen(3000,'1.2.3.4');