Open HTTP port 80 on CentOS

Got from here.

1. Look at the current iptables
# iptables --line -vnL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination
1        0     0 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           udp dpt:53
2        0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           tcp dpt:53
3        0     0 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           udp dpt:67
4        0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           tcp dpt:67
5     195K  212M ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
6        3   252 ACCEPT     icmp --  *      *       0.0.0.0/0            0.0.0.0/0
7       74  5440 ACCEPT     all  --  lo     *       0.0.0.0/0            0.0.0.0/0
8       16   864 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           state NEW tcp dpt:22
9     170K   39M REJECT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           reject-with icmp-host-prohibited

2. Inject rule, as long as it's before the REJECT line
# iptables -I INPUT 5 -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT

3. Save
# service iptables save

4. Add httpd_t to the list of permissive domains (So we don't need to turn off selinux)
# yum install policycoreutils-python
# semanage permissive -a httpd_t

Open up Firewall of Fedora Core 19

Here's the whole write up on FirewallD.
How you would open up http and https, or specific ports for your box:

$ sudo firewall-cmd --permanent --zone=public --add-service=http
$ sudo firewall-cmd --permanent --zone=public --add-service=https

Restart the firewall:

$ sudo systemctl restart firewalld.service

Or on specific ports:

$ sudo firewall-cmd --permanent --zone=public --add-port=9393/tcp

Restart the firewall:

$ sudo systemctl restart firewalld.service