Verify that firewall is disabled

[root@server ~]$ service iptables status
[root@server ~]$ /sbin/iptables -L -v -n

 

Stop/ Disable

[root@server ~]$ systemctl stop iptables
[root@server ~]$ systemctl disable iptables
[root@server ~]$ systemctl stop firewalld
[root@server ~]$ systemctl disable firewalld

 

[root@server ~]$ service iptables stop
[root@server ~]$ service ip6tables stop
[root@server ~]$ service firewalld stop

 

[root@server ~]$ chkconfig iptables off
[root@server ~]$ /etc/init.d/iptables save

 

Check connection to the server

[root@server ~]$ ss -an | grep tcp
[root@server ~]$ nstat
[root@server ~]$ iptables -L INPUT -v -n

 

Port info

[root@server ~]$ netstat -anp | grep 8080
[root@server ~]$ netstat -an | grep 1521

 

Check if the port is associated with the official list of known services

[root@server ~]$ cat /etc/services | grep 8080

 

Allow ports

[root@server ~]$ vi /etc/rc.d/init.d/network
iptables -I INPUT 1 -p TCP --destination-port 1521 -j ACCEPT