
One quirky thing about RedHat is that they are _very_ conservative as to the packages they include in their repositories. In this case, PHP 5.1.6 was the latest version and I needed at least 5.2 for a Drupal 6 installation.

Step 1
------

[atomicorp.com](http://atomicorp.com/) hosts a repository which we'll add:  

wget -q -O - http://www.atomicorp.com/installers/atomic.sh | sh

Step 2
------

Then we'll install the latest version of PHP using yum:  

```
yum install php
```

Or if an older version of php is already installed:  

```
yum update php
```

Step 3
------

Restart the webserver:  

```
/etc/init.d/httpd restart
```
  
And that's it! Now you should have PHP 5.2 installed.  
  
Resources:  

*   [http://bluhaloit.wordpress.com/2008/03/13/installing-php-52x-on-redhat-es5-centos-5-etc/](http://bluhaloit.wordpress.com/2008/03/13/installing-php-52x-on-redhat-es5-centos-5-etc/)
*   [http://mayurchaudhari.wordpress.com/2009/02/23/upgrade-php-to-5-2-x-using-yum/](http://mayurchaudhari.wordpress.com/2009/02/23/upgrade-php-to-5-2-x-using-yum/)
*   [http://iptrees.wordpress.com/2009/10/11/how-to-upgrade-to-php-5-2-x-on-centosrhelfedoraedora/](http://iptrees.wordpress.com/2009/10/11/how-to-upgrade-to-php-5-2-x-on-centosrhelfedoraedora/)
*   [http://netfirms.com/community/threads/35-Upgrade-to-PHP-5-2-x-on-CentOS-5-Plesk](http://netfirms.com/community/threads/35-Upgrade-to-PHP-5-2-x-on-CentOS-5-Plesk)


Installing PHP 5.2 on CentOS 5


I decided to try out HostGator's VPS Hosting for a new Drupal project I'm working on. This is the first post in a series that will touch on various aspects of VPS management, Drupal, and video distribution.  
  
I wanted to set up a custom nameserver partially for the learning experience and partially to gain total control over load balancing, if necessary in the future. First of all, I signed up for the Level 1 VPS at HostGator. The low cost and scalability of their plans attracted me, though I've never used them before. After doing some research, I decided to setup a simple nameserver hosted on the VPS that points to my domains on the server. Keep in mind that this is a very simple setup that is not necessarily secure. Check out the resources at the end of this post if you want to dig deeper.  
  
The three files we will need to create or edit are:  

*   /etc/resolv.conf
*   /etc/named.conf
*   /var/named/chroot/var/named/example.com.db

This assumes that you're running BIND in a chroot jail (which is the default setup for HostGator's VPS at the moment).

Step 1
------

Create or edit resolv.conf so that it looks like this:  

File: /etc/resolv.conf
```
nameserver 127.0.0.1
```

You should comment out any other lines if they exist. This tells the host to look at its own nameserver for domain name lookups.  

Step 2
------

Next, create or edit named.conf so that it contains:  

File: /etc/named.conf
```
options {  
  listen-on port 53 { any; };  
};  
zone "example.com" {  
 type master;  
  notify no;  
  allow-query { any; };  
  file "/var/named/chroot/var/named/example.com.db";  
};
```

This tells BIND to listen on port 53 (the default DNS port number) from any IP. The _zone_ section should be repeated for every domain you're serving. The _file_ part should point to each zone file.  
  

Step 3
------

Now we need to create a zone file for the domain:  

File: /var/named/chroot/var/named/example.com.db
```
$TTL 14400  
@ 86400 IN SOA ns1.example.com. admin@example.com. (  
    2008021501 ; serial, todays date+todays  
    86400 ; refresh, seconds  
    7200 ; retry, seconds  
    3600000 ; expire, seconds  
    86400 ) ; minimum, seconds  
example.com. 86400 IN NS ns1.example.com.  
example.com. 86400 IN NS ns2.example.com.  
ns1 IN A 111.222.333.444  
ns2 IN A 111.222.333.445  
example.com. IN A 111.222.333.444  
localhost.example.com. IN A 127.0.0.1  
example.com. IN MX 0 example.com.  
mail IN CNAME example.com.  
www IN CNAME example.com.  
ftp IN A 111.222.333.444
```

Basically, this file sets up each nameserver as ns1.example.com (111.222.333.444) and ns2.example.com (111.222.333.445). This matches the nameservers to each IP.  

Step 4
------

Then, restart BIND:  
```
service named restart
```

Step 5
------

Finally, you need to contact your registrar and register your new nameservers ns1.example.com and ns2.example.com. [Here are some step-by-step instructions](http://www.whsupport.net/register_nameservers.php) for the most common registrars.  
  
And that should do it! Please check out the following resources, as this short example just barely scratches the surface of DNS configuration:  

*   [Quick HOWTO : Ch18 : Configuring DNS](http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch18_:_Configuring_DNS#BIND)
*   [DNS/BIND: Create a basic zone file](http://www.tech-recipes.com/rx/305/dnsbind-create-a-basic-zone-file/)
*   [Chroot-BIND HOWTO](http://www.faqs.org/docs/Linux-HOWTO/Chroot-BIND-HOWTO.html)
*   [Bind: Quick install guide to install and setup Bind (DNS server) in secure (chroot) environment in Linux (CentOS, Redhat Enterprise (RHEL), Fedora).](http://crazytoon.com/2007/06/21/bind-quick-install-guide-to-install-and-setup-bind-dns-server-in-secure-chroot-environment-in-linux-centos-redhat-enterprise-rhel-fedora/)


How to Set Up a Simple BIND Nameserver on CentOS


As I was setting up my home testing server (Ubuntu Server 9.04), I kept running into issues with Deny Hosts while testing my server's authentication methods. It was a real pain to find out how to remove an IP that has been blocked.  
  
First of all, references to WORK\_DIR point to /var/lib/denyhosts/ or something similar on your system.  
The default location for the hosts.deny file is /etc/hosts.deny.  
  
Here's the method I used to unblock an IP:  

1.  Stop DenyHosts
2.  Remove the IP address from hosts.deny
3.  Remove all lines containing the IP address from the following files:  
    *   WORK\_DIR/hosts
    *   WORK\_DIR/hosts-restricted
    *   WORK\_DIR/hosts-root
    *   WORK\_DIR/hosts-valid
    *   WORK\_DIR/users-hosts
4.  Consider adding the IP address to WORK\_DIR/allowed-hosts
5.  Start DenyHosts


Unblocking an IP from Deny Hosts


Since installing Ubuntu on my home machine about a year ago, I've compiled a list of simple commands that I frequently need, but always have to look them up in the man pages:  

  

scp /path/to/local/file username@host:/path/to/remote/location
- copies a local file to a server via ssh

find . -name filename | xargs -I % rm -rf %
- finds all instances of filename and remove them (CAREFUL!)

ln -s /target/path/to/file /path/to/link
- creates a symbolic link

ls -d \*/
- lists all directories in cwd

du -hs /path/to/directory
- prints the size of directory

du -h --max-depth=1 /path/to/directory
- prints the size of each folder and file in directory


Handy Linux Commands

To hide page elements without IE showing them for a split second when the page loads, add an id to your body tag as soon as the DOM loads. You'll want to do this even before you load any JavaScript libraries like jQuery or Prototype.  
  
This is what your page layout should look like:  

<Code language="html">
{`<!DOCTYPE HTML>  
<html>  
<head>  
    
</head>  
<body>  
    
  <script type="text/javascript">  
document.getElementsByTagName('body')\[0\].id = 'js';  
  </script>  
    
</body>  
</html>
`}
</Code>
  
This will add the 'js' id to your body tag only if the user has Javascript enabled. Adding the script right away makes sure that the elements are hidden as soon as possible, rather than having to wait for jQuery/Prototype to load, etc...  
  
Then, in your CSS file create a selector for your element like so:  

<Code language="css">
{`#element {  
  /\* css for all users \*/  
}  
body#js #element {  
  /\* css for javascript enabled browsers \*/  
  display: none;  
}
`}
</Code>
  
This will hide the element so you can display it later with your JavaScript code, but show it for non-JavaScript users. Ahhh, beautiful degradation.

linux

Installing PHP 5.2 on CentOS 5

How to Set Up a Simple BIND Nameserver on CentOS

Unblocking an IP from Deny Hosts

Handy Linux Commands

Instantly Hide Page Elements