Ubuntu – Port Open to Localhost but Not Actual IP

portUbuntu

I'm running ubuntu inside a virtual machine with VMWare. I'd like to connect to port 8080 from outside the VM. I can't copy and paste text from the VM so you'll have to trust me on this:

The VM's IP address is 192.168.127.129

From the VM:

'nmap localhost' shows ports 22, 80, 1521, and 8080 open.
'nmap 192.168.127.129' only shows ports 22, 80, and 1521 open.

Am I missing something obvious here?

Best Answer

localhost is an internal interface with IP address 127.0.0.1.

192.168.127.129 belongs to your external interface (which in this case happens to be a virtual network interface as opposed to a physical one). localhost and 192.168.127.129 are two different interfaces and so you will get different results, depending on how your network services are configured.

Whatever service you have running on port 8080 only listens on the loopback interface and is not available to the rest of the world, only TCP/IP clients connecting from localhost.

Related Solutions

Node.js – Node.js Not Accessible from External IPs on Ubuntu

Thanks for adding the last netstat output, it really helped. You can't access node.js from outside because it is listening on localhost IP i.e 127.0.0.1. You need to configure node.js to listen on 0.0.0.0 so it will be able to accept connections on all the IPs of your machine.

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n');
}).listen(8080, "0.0.0.0");
console.log('Server running at http://0.0.0.0:8080/');

CentOS – How to Open Port 8080

I always like to add a comment and limit scope in my firewall rules.

If I was opening up tcp port 8080 from everywhere (no scope limiting needed) for Tomcat I would run the following command

iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -j ACCEPT -m comment --comment "Tomcat Server port"

Then make sure to save your running iptables config so that it goes into effect after the next restart

service iptables save

Note: you'll need to have the comment module installed for that part to work, probably a good chance that it is if you are running Centos 5 or 6

P.S.

If you want to limit scope you can use the -s flag. Here is an example on how to limit traffic to 8080 from the 192.168.1 subnet

iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -s 192.168.1.0/24 -j ACCEPT -m comment --comment "Tomcat Server port"

Best Answer

Related Solutions

Node.js – Node.js Not Accessible from External IPs on Ubuntu

CentOS – How to Open Port 8080

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