Conifguring Apache in Linux machine

Here are the detailed steps if its already installed

check if its already installed 


# httpd -v  (you may get command not found ,so try this too)
#  whereis httpd   (output in my machine /usr/sbin/httpd ) so using the output where the command is
# /usr/sbin/httpd -v
This should give some output if its already installed like
 Server version: Apache/2.2.3
 Server built:   May 2 2012 13:21:52


====Now checking part is done =============

Configure


# sudo  /etc/httpd/conf/httpd.conf

It throws this error

Starting httpd: (13)Permission denied: make_sock: could not bind to address [::]:80
(13)Permission denied: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs                [FAILED]

The problem here is that the port is used by some other service or something ,so either you have to kill it or configure new port on which httpd can be used or apache.(I prefer the latter as no risk in that)

For killing 
#  ps -aux | grep httpd
Find the pid which is using this
# kill -9  //make sure you don't kill any important process 

Configuring new port

Run this command

# sudo semanage port -l | grep -w http_port_t  ( To view the ports SELinux allows httpd to listen on:)

    O/p on machine is 80, 443, 488, 8008, 8009, 8443 

Edit /etc/httpd/conf/httpd.conf as the root user. Configure the Listen option so it lists a port that is not configured in SELinux policy configuration for httpd like 12345

Go here and add Listening port info

# sudo vi  /etc/httpd/conf/httpd.conf 

Add this line 

Listen 127.0.0.1:12345

Now you have to configure  SELinux to allow httpd to listen on port 12345,use this command

# sudo semanage port -a -t http_port_t -p tcp 12345

Start apache again

# sudo /etc/rc.d/init.d/httpd start

Note : 1. You may hav to add /usr/sbin and /usr/bin in your path  if its not already

            2. You can set SELinux disabled using setenforce 0 command though never advisable.

====Done=====