Assume : domain to be accessed is accessible via the url domain.com
Varnish caching engine will run infront of Apache in port 80, and internally forward the requests to Apache.

Installation of Varnish:

1. Download Varnish source file from sourceforge.net
2. Install libraries below via yum, as well as any other dependencies.

yum install logrotate libgomp gcc cpp binutils kernel-headers glibc-headers glibc-devel pcre-devel

3. Do ./configure, make, make install to install varnish
4. Configure Apache to listen on another port 8080 and restart Apache for changes to reflect.
5. Start Varnish as below, before that you can configure the default config file /usr/local/etc/varnish/default.vcl as mentioned in (6)
If varnish available under services, configure the file below with the parameters below:

Code:

DAEMON_OPTS=”-a :80 \
-T localhost:6082 \
-f /usr/local/etc/varnish/default.vcl\
-S /etc/varnish/secret \
-s malloc,200M \

And do

Code:

/etc/rc.d/init.d/varnish start

If its not available under services, start it as below:

Code:

varnishd -f /usr/local/etc/varnish/default.vcl -T 127.0.0.1:6082 -a 0.0.0.0:80 -s malloc,200M

If you want to connec to the commandline interface use

varnishd -f /usr/local/etc/varnish/default.vcl -T 127.0.0.1:6082 -a 0.0.0.0:80 -s malloc,200M -d

6. A sample config file for Apache is as below. It can be tweaked as per customization required as outlined in http://www.varnish-cache.org/trac/wiki/Introduction

Code:

backend default {
.host = “69.50.217.14″;
.port = “8080″;
}

acl purge {
“localhost”;
“69.50.217.14″;
}

sub vcl_recv {

// Strip cookies for static files:
if (req.url ~ “\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$”) {
unset req.http.Cookie;
return(lookup);
}

// Remove has_js and Google Analytics __* cookies.
set req.http.Cookie = regsuball(req.http.Cookie, “(^|;\s*)(__[a-z]+|has_js)=[^;]*”, “”);

// Remove a “;” prefix, if present.
set req.http.Cookie = regsub(req.http.Cookie, “^;\s*”, “”);

// Remove empty cookies.
if (req.http.Cookie ~ “^\s*$”) {
unset req.http.Cookie;
}

if (req.request == “PURGE”) {
if (!client.ip ~ purge) {
error 405 “Not allowed.”;
}
purge(“req.url ~ ” req.url ” && req.http.host == ” req.http.host);
error 200 “Purged.”;
}
}

sub vcl_hash {
if (req.http.Cookie) {
set req.hash += req.http.Cookie;
}
}

sub vcl_fetch {

// Strip cookies for static files:
if (req.url ~ “\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$”) {
unset beresp.http.set-cookie;
}

// Varnish determined the object was not cacheable
if (!beresp.cacheable) {
set beresp.http.X-Cacheable = “NO:Not Cacheable”;
}

// You don’t wish to cache content for logged in users
elsif(req.http.Cookie ~”(UserID|_session)”) {
set beresp.http.X-Cacheable = “NO:Got Session”;
return(pass);
}

// You are respecting the Cache-Control=private header from the backend
elsif ( beresp.http.Cache-Control ~ “private”) {
set beresp.http.X-Cacheable = “NO:Cache-Control=private”;
return(pass);
}

// You are extending the lifetime of the object artificially
elsif ( beresp.ttl < 1s ) {
set beresp.ttl = 300s;
set beresp.grace = 300s;
set beresp.http.X-Cacheable = “YES:Forced”;
}

// Varnish determined the object was cacheable
else {
set beresp.http.X-Cacheable = “YES”;
}

return(deliver);
}

7. Varnish Cache log can be started using the command below:

Code:

/usr/local/bin/varnishlog -w /tmp/vlog &

And tailing /tmp/vlog to see the dump of the requests handled by Varnish.

8. Any other problems with Apache can be checked from Apache error log, for instance http://domain.com shows a blank page.
9. You can also benchmark the difference in performance before and after using Varnish using the Apache bench marking tool ab and the commandline below:

Code:

ab -n1000 -c100 http://domain.com/

Issue :

How to enable SuPHP ?

Solution :

Login to WHM.

Go to “Service Configuration >> Apache Configuration >> Configure PHP and Suexec” and check if SuPHP is available in the drop down menu. If it is available then select it and save the configuration after a dry run.
SuExec should also be available in the same drop down with an on/off option.

If SuPHP is not available then you need to run EasyApache via “WHM >> Software >> EasyApache (Apache Update)” and select SuPHP in the available options. You can also run EasyApache via console by using the following cPanel scipt :

/scripts/easyapache

Issue :

How can you access cPanel like, say, http://domainname.com/xyz ? This is for security purposes.

Solution :

This can be done but not recommended as it would not be of much effect security-wise.
Even if you change it, cPanel/WHM would still run on the standard ports (2082/2083 & 2086/2087) which is known to everyone. If you have a valid cPanel license then you can contact their support and get the ports changed. This coupled with a strong password (change regularly) should be good enough.

However, coming back to the original question, you can achieve it in the following way :

Go to /usr/local/apache/conf/httpd.conf
Find the following line :

ScriptAliasMatch ^/?cpanel/?$ /usr/local/cpanel/cgi-sys/redirect.cgi

Comment it out by adding a ‘#’ at the beginning and add the following line below that line :

ScriptAliasMatch ^/?xyz/?$ /usr/local/cpanel/cgi-sys/redirect.cgi

Issue :

Need to redirect https://domain.com to https://www.domain.com for SSL purposes.

Solution :

Use the following code in the htaccess file under the public_html folder for the concerned domain :

RewriteEngine On
RewriteCond %{HTTP_HOST} ^domain.com [NC]
RewriteRule ^(.*)$ https://www.domain.com/$1 [L,R=301]

Issue :

How to change Apache Time Out for a single website ?

Solution :

Even though Apache Timeout is a global environment directive, you can still change that for a single domain by modifying the corresponding VirtualHost entry for the domain.

It should look something like this :

ServerName domainname.com
ServerAlias www.domainname.com
DocumentRoot /home/user/public_html
ServerAdmin webmaster@domainname.com
Timeout xxx
.
.
.

Do restart the httpd service after making the alterations.

Issue :

An application requires execution of a binary file. A separate account has been created but do not want to turn on the exec() function citing security concerns. What is the best way to go about this ?

Solution :

If it is a php suexec server then you can place a custom php.ini file under the concerned folder in the account created. Copy the content from the server php.ini but remove the required function from the ‘disable_function’ list in the custom php.ini. This will affect only the account and not the entire server.

If it is not a php suexec server then place the following code in the VirtualHost entry for the domain and restart apache.

< IfModule mod_php5.c >
php_admin_value disable_functions ” ”
< /IfModule >

Include the functions that you want to keep disabled for the account within the quotes in the above code.

Issue :

On a brand new server with a clean cPanel install, apache does not want to start.

root@server [~]# service httpd start
Syntax error on line 416 of /usr/local/apache/conf/httpd.conf:
UserDir “enable” keyword requires a list of usernames
root@server [~]#

Fix :

This usually happens when Apache mod_userdir Tweak is enabled in WHM before adding any accounts. This creates blank UserDir directives in the httpd.conf file which will not let Apache start.
To get around this, simply disable the tweak until the first account is created.
However, cPanel is reviewing this and should be fixed soon.

Issue :

After the migration of IPs between two servers, sites are coming up with the default cPanel page.

Solution :

This can be due to an IP mismatch. Make sure that the DNS records and the Apache VirtualHost for the domains are configured on the same IP.
Check the IP in “WHM >> Show IP Address Usage” and see if it matches with the IP you get on pinging the site from your local system.

If there is no mismatch then it should just be a case of propagation delay.

Issue :

When accessing the IP, it brings up the apache/cPanel success page instead of the website.

Solution :

If it is a shared IP then apache serves that generic page which is the default.
You can manually change that by editing /usr/local/apache/htdocs

OR

In newer versions of cPanel, you can do that via WHM > Web Template Editor > Default Website Page.

Issue :

The DNS has not yet propagated. Meanwhile, need to access the account via serverIP/~username but it does not work.

Fix :

1. Log in to the server WHM as ‘root’.
2. Go to Main >> Security Center >> Apache mod_userdir Tweak.
3. Make sure that it is allowed for the particular domain and/or the entire server.

Issue :

When you create a sub-domain, cPanel points it to the corresponding folder under public_html by default. How to point it to a folder outside the public_html?

Solution :

This cannot be done via cPanel/WHM but can be achieved if you have ‘root’ SSH access to the server.

1. Open the apache configuration file — /usr/local/apache/conf/httpd.conf
2. Search for the virtual host entry for your sub-domain.
3. Edit the document root of your sub-domain to match the desired location.
4. Save and Exit. Restart apache.

Note : cPanel rebuilds httpd.conf from userdata files and its overwritten on every cPanel update, on every account creation, subdomain addition, or any such activity related to apache and any manual changes you make will be overwritten. To make permanent changes to a subdomain’s root folder :

1. Edit the file /var/cpanel/userdata/username/subdomain.domain.com file, change the path and save it.
2. Run /scripts/rebuildhttpdconf
3. Restart apache.

To learn how you can preserve the changes in httpd.conf during EasyApache, click here.

Issue :

How to enable the PHP extension–FreeType on a server running cPanel/WHM and apache?

Solution :

You need to re-compile apache and php with freetype . This can be done via the command line or through WHM.

Command line :
Run /scripts/easyapache and select “ttf” for freetype.

WHM:
You can enable freetype via WHM >> software >> Apache Update >> Load Previous Config and select TTF(FreeType)
Start Build

Issue :

While some construction is going on the site, all pages on the website should go to the index page.

Solution :

This can be easily achieved by using the following code in your .htaccess file :

< IfModule mod_rewrite.c >
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.html [L]
< /IfModule >

Issue :

How to disable access to /whm and /cpanel for all domains except the server hostname?

Solution :

This would need customization of the httpd.conf file.

First, edit the httpd.conf and remove any lines pertaining to forwarding of domains to /cpanel and /whm.
Secondly, run the following command to distill the file :

/usr/local/cpanel/bin/apache_conf_distiller –update –main

Finally, restart Apache.

service httpd restart

Issue :

Regardless of somebody accessing the site with or without the ‘www’ , it should always go to http://domain.com

Solution :

Use the following htaccess code :

RewriteEngine on
RewriteCond %{HTTP_HOST} ^www.domain.com
RewriteRule ^(.*) http://domain.com/$1 [R]