install and run apache2 in centos 7


1. download the latest apache2 from http://httpd.apache.org/download.cgi
2. the current lastest version is https://www-eu.apache.org/dist//httpd/httpd-2.4.41.tar.gz
3. tar -zxvf httpd-2.4.41.tar.gz; cd httpd-2.4.41; ./configure; make; make install
4. the installed apache is located at /usr/local/apache2
5. to activate it, use /usr/local/apache2/bin/apachectl -f /usr/local/apache2/conf/httpd.conf

6. If you want your server to continue running after a system reboot, add a call to apachectl to your system startup files. This will start Apache at boot time.

Refer to https://geekflare.com/systemd-start-services-linux-7/

for managing and starting processes on boot


vi /etc/systemd/system/chat_server.service

and then the following is needed.

##################
[Unit]
Description=Chat Server Service
After=network.target

[Service]
Type=simple
User=ankush
ExecStart=/usr/local/apache2/bin/apachectl -f /usr/local/apache2/conf/httpd.conf
Restart=on-abort

[Install]
WantedBy=multi-user.target
##################

Save the file and the next step is to reload the systemd daemon

 systemctl daemon-reload

and to start the service we just created:

 systemctl start chat_server

check the selinux status (/etc/sysconfig/selinux) using sestatus

refere to https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands
to set iptables

refer to https://linuxize.com/post/how-to-install-iptables-on-centos-7/:
yum install iptables-services

firewall-cmd --state  ## to check firewall state

To check what zones are used by your network interface(s) type:

firewall-cmd --get-active-zones

firewall-cmd --zone=public --list-all

must edit /etc/hosts so that it reads similar to 

127.0.0.1   comsics comsics.usm.my localhost4 localhost4.localdomain4
::1         comsics comsics.usm.my localhost6 localhost6.localdomain6
10.205.19.208 comsics comsics.usm.my