How to open port in Linux

Question

I have installed and web application which is running on port 8080 on RHEL (centOS). I only have command line access to that machine. I have tried to access that application from my windows machine from which I am connected to server via command-line, but it is giving connection time out error.

Then I have tried to open port 8080. I have added following entry into the iptables.

-A INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -j ACCEPT

After adding this into the iptables I have restarted it with - /etc/init.d/iptables restart

But still I am not able to access that application from my windows machine.

Am I doing any mistake or missing something?

Solution 1

First, you should disable selinux, edit file /etc/sysconfig/selinux so it looks like this:

SELINUX=disabled
SELINUXTYPE=targeted

Save file and restart system.

Then you can add the new rule to iptables:

iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

and restart iptables with /etc/init.d/iptables restart

If it doesn't work you should check other network settings.

Solution 2

The following configs works on Cent OS 6 or earlier

As stated above first have to disable selinux.

Step 1 nano /etc/sysconfig/selinux

Make sure the file has this configurations

SELINUX=disabled

SELINUXTYPE=targeted

Then restart the system

Step 2

iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

Step 3

sudo service iptables save

For Cent OS 7

step 1

firewall-cmd --zone=public --permanent --add-port=8080/tcp

Step 2

firewall-cmd --reload

Comments

[Niraj Chapla]

selinux is disable and selinuxtype is set to targeted and append rule to the iptables. Restarted the iptables as well but still not working. Need to check other network configuration

[kmehta]

@jabaldonedo I get a 9001 socket exception at exactly 2 hours of a mongodb load from a centos server. Could this be a solution to that? If so, in your opinion, do i have to do this on both the remote host and the requesting host or just the remote host? Thanks!

[jabaldonedo]

Maybe your problem is not related with CentOS, are you sure that your application is correctly configured? that error is a connection issue from MongoDB. I don't know what application are you trying to run, but I suggest you to check again its configuration and/or if you can, ask for some support help.

[kmehta]

Yeah it's a mongodb client method "db.cloneCollection". I haven't found any sort of timeout configuration either on the mongo client or the mongod server process.

[blackbird]

Restarting iptables flused my new rule

[AndrewT]

Step 3 fails save is not a valid parameter

[Sireesh Yarlagadda]

Try this for restart iptables-save

[DisplayMyName]

Did you see it's for CentOS 6 or earlier? Works for me.

[manudicri]

Bad argument 'NEW'