Firewall configuration in Linux (CentOS/Red Hat)

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Really thanks to you for your interest in this topics. :)

Hope that you are enjoying Linux learning. So lets see, what is in todays post? Today I’m going to share about some knowledge about the configuration of Firewall in Linux (CentOS/Red Hat)

So lets start the firewall configuration:

Firewall configuration in Linux (CentOS/Red Hat)

At first we’ll log in as super user. (By “su-” or “su root”)

[ece@localhost Desktop]$ su –

Password:

Last login: Mon May 9 10:33:15 EDT 2016 on pts/1

 

just checked our firewal is working well or not.

 

[root@localhost ~]# systemctl enable firewalld

[root@localhost ~]# systemctl restart firewalld

[root@localhost ~]# systemctl status firewalld             ; =>> Recent status of firewall

So we got the output of the system:

 

• firewalld.service – firewalld – dynamic firewall daemon

Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)

Active: active (running) since Tue 2016-05-10 00:22:22 EDT; 7s ago

Main PID: 4299 (firewalld)

CGroup: /system.slice/firewalld.service

└─4299 /usr/bin/python -Es /usr/sbin/firewalld –nof…

 

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:23 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:24 localhost.localdomain firewalld[4299]: 2016-05-…

May 10 00:22:24 localhost.localdomain firewalld[4299]: 2016-05-…

Hint: Some lines were ellipsized, use -l to show in full.

 

Now we’ll examine the status of IP table:

 

[root@localhost ~]# systemctl status iptables

 

• iptables.service

Loaded: not-found (Reason: No such file or directory)

Active: inactive (dead)

 

[root@localhost ~]# systemctl mask iptables

 

Created symlink from /etc/systemd/system/iptables.service to /dev/null.

 

[root@localhost ~]# firewall-cmd –state

running

 

[root@localhost ~]# firewall-config

[root@localhost ~]# firewall-cmd –get-default-zone

public

 

[root@localhost ~]# firewall-cmd –permanent –zone=public –list-all

public (default)

interfaces:

sources:

services: dhcpv6-client ssh

ports: 53/tcp 80/tcp 53/udp

masquerade: no

forward-ports:

icmp-blocks:

rich rules:

 

[root@localhost ~]# firewall-cmd –zone=public –list-all

public (default)

interfaces:

sources:

services: dhcpv6-client ssh

ports: 80/tcp 53/udp 53/tcp

masquerade: no

forward-ports:

icmp-blocks:

rich rules:

 

[root@localhost ~]# firewall-cmd –set-default-zone public

Warning: ZONE_ALREADY_SET: public

[root@localhost ~]# firewall-cmd –set-default-zone public

Warning: ZONE_ALREADY_SET: public

[root@localhost ~]# echo ‘welcome to https’ > /var/www/html/index.html

[root@localhost ~]# firewall-cmd –permanent –zone=public –add-port 443/tcp

success

 

[root@localhost ~]# firewall-cmd –reload

success

[root@localhost ~]# firewall-cmd –permanent –zone=public –add-service=https

success

 

Finally we’ve reloaded firewall.

[root@localhost ~]# firewall-cmd –reload

success

[root@localhost ~]#

 

Screenshots:

 

So hope that you’ve learn some thing about the configuration of firewall in Linux (CentOS/Red Hat).