First question how do you change hostname on centos?

Also is it needed?

Now lets say my website is www.example.com
External IP is 66.19.240.12
Internal IP is 192.168.1.4

hostname servix

I am guessing in /etc/hosts

127.0.0.1 localhost
66.19.240.12 or is it 192.168.1.4 servix.example.com servix

and in FreeDns A Record should point to 66.19.240.12 both example.com and www?

Or this isn't needed?

To change the hostname:

See man hostname for more.

If you want the public to have access to your site, the A Record must point to the public-facing ip address. Beyond that, as for your DNS questions, I must confess I'm not exactly sure what you are asking.

If on CentOS 7:

If on CentOS 6, use the `hostname` command like you just demonstrated. The `hostname` command will still work on CentOS 7, but with the introduction of systemd, the recommendation is to use hostnamectl going forward.

I'm assuming you're using a NAT or PAT (IP address or port translation through a router or firewall), since you provided both a public and a private IP address. If you are using a NAT or PAT, it's usually better to use the private IP address:

Keep in mind this is situational. You may find that with your application, it's better to use the public IP address. The only difference this makes is how the server resolves its own host name.

EDIT: Forgot to answer your final question...

I'm a bit confused about what you're trying to make resolve. In the example you provided, servix was your host name.

In the simplest cases, you have '@' (no subdomain) and 'www' resolve to the same IP address. So yes, you probably want example.com and www.example.com to resolve to 66.19.240.12.

If you also want servix.example.com to load something from your server, it will also need to resolve to 66.19.240.12.

Ok you can name hostname anything you like am I correct? I am just confused on how DNS works.

In FREEDNS A record I have the external Ip of my machine pointing. I got a warning that my A record don't point to servers ip address which I am assuming because I didn't put 192.168.1.4 in /etc/hosts

So if my hostname is Servix I just add that to my domain name in the hosts file?

Yeah, you can name the hostname anything you want. It doesn't have to be the same as a public DNS record, but it often is.

Where did you see the warning that your A record doesn't point to the server's IP address? I don't think that would have anything to do with your hosts file, but I would have to know where it came from to be sure.

I was using a script to configure Magento Server automatically and gave this warning that Servers address is 192.168.1.4 but points to different IP which was my external.

Now I also have a problem with SELinux. I put it in permissive mode and ran the following:

grep "SELinux is preventing" /var/log/messages" and got nothing, but can't access site if I enable SELinux to enforcing.

That should be a warning you can ignore. You may have to add a line that forces (www.)example.com to resolve to localhost or your private IP address, but it's best to leave your /etc/hosts file in its default state if you can.

As for SELinux, I personally have it disabled on many of my servers. I know it's bad practice, but it's just one of those things I haven't looked at doing properly yet. I recommend starting a new thread asking for help with SELinux, since people browsing the topics are seeing this thread as a host name issue. That way you'll catch the attention of the SELinux experts. In fact, you probably want to get everything set up and working with SELinux disabled, then come back and configure it last.

Good luck!

I was told if your not running DNS on your own server /etc/hosts you don't have to do anything. It's only when you run own DNS. Everything is working when I disable SELinux. Thanks for your time.