Apache Web Server Information

Since the beginning of 1996 (at least), Apache has been the web server of choice for the planet. It has enjoyed as high as 80% of the market share for publicly accessible webservers.
Note: This area is for Apache version 2. (AKA: Apache2)

Let's start by installing apache2 on an Ubuntu machine. In a terminal type:

sudo apt-get install apache2-mpm-prefork apache2-doc

The dependencies apache2-utils apache2.2-common should be picked up and will ask for conformation to be installed also. It should look something like:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  apache2-utils apache2.2-common
The following NEW packages will be installed:
  apache2-doc apache2-mpm-prefork apache2-utils apache2.2-common
0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 3051kB of archives.
After this operation, 14.7MB of additional disk space will be used.
Do you want to continue [Y/n]?

Type "y", then enter.
When it's finished, you should be able to go to http://localhost on that machine or http://theipaddress of that machine from another machine. You should get a web page the says It works!

The file you are seeing is index.html and the default location is in /var/www/

More

• Howto install “Webmin”
• mod_evasive Apache module
• Error and Access Logs

Howto install “Webmin” on Ubuntu or a Debian based server.

One of the first things to do on your new web server (IMHO, of course), is to set up Webmin. Webmin is a web based application for the server and domain administration of a Linux machine and/or cluster.

First:

Go to the Webmin site and download the .Deb file listed on the top of the home page. (As of this writing, it was top right.)

Second:

If you have some form of display manager (ie, Gnome, KDE, etc.) running on the server, open a web browser and type in https://localhost:10000
Note: https and note the :10000. This is a secure (ssl) connection and is negotiating through port 10000.
If you cannot use a browser on the server, go to a computer on the same network and open a browser with https://yourservername:10000

Third:

This should bring up a login page. You will need to have root access or use an account that can get root access. (Be one of the admin group on the server) Once logged in, go to the Webmin configuration settings page.

Forth:

Do this step as soon as possible. We need to change the port on which webmin is accessed. Change the port Webmin listens on to 10002. You can change it to whatever you want later. We want the webmin service to run on a port that will not conflict with something else. You may want to consult an authoritative port list, if you are unsure. I like to use the official one on IANA port list. When a change of the list happens, (once or twice a year) this is where it will be posted.
Note: IANA seems to be going throught (xml) growing pains and the above link outputs a very slow xml file. You may want to go to the text version instead.

If you had previously installed whitelister (for postfix) which uses port 10000, you will start getting a couple of different errors, all dealing with conflicts with port 10000. Trying to reinstall webmin and you may get errors like “port 10000 already in use” If you are having this problem right now and need answers fast; try running this command in a terminal:

sudo netstat -antupl | grep :10000

If you get an output that looks like:

tcp        0      0 127.0.0.1:10000         0.0.0.0:*               LISTEN      4948/whitelister

you can stop whitelister an any conflicting service with:

sudo /etc/init.d/whitelister stop

Fifth:

For the purpose of this instruction, we'll assume port 10002. Once changed you will have to re-login to your server using the new port number. So, it should now look like: https://yourservername:10002 If you are on that machine you can also use https://localhost:10002

This should give a basic webmin running. I'll cover how to work with Apache within (and outside of) Webmin next. As always; if you need help with something, there's an email link on the bottom of this page. Send me an email and I'll put together what I know and send it out right away.

Module mod_evasive

This module is designed to assist in limiting concurrent conections from the same address. If you are wondering why. Watch your apache log sometime with a command like:
tail -f /var/log/apache2/access.log
Every once in awhile, there will be some annoying bot hit your server a baggazillion times.
This will help.
Install the package libapache2-mod-evasive in either synaptics or in a terminal
sudo apt-get install libapache2-mod-evasive

You'll need to edit your apache2.conf file
Put the following towards the end and restart or reload apache:

<IfModule mod_evasive20.c>
    DOSHashTableSize    3097
    DOSPageCount        2
    DOSSiteCount        50
    DOSPageInterval     1
    DOSSiteInterval     1
    DOSBlockingPeriod   22
#optional
    #DOSEmailNotify      youremail@yourdomain.tld
    #DOSSystemCommand    "run some command"
    #DOSLogDir           "/var/log/mod_evasive/evasive.log"
#If you use the last one, don't forget to make the directory and file
</IfModule>

Error and Access Logs

One of the nicer things about Linux/BSD operating systems is the ability to look at the files of everything installed. One of the utilities that come pre-installed in most distributions is “tail”.
Tail prints out the last ten lines of a file. With the “-f” switch it follows the changes as it happens. The “-v” switch makes the output more verbose.

So you got your pretty web site up and running and you want to see what or who is viewing your site.
Open your favorite terminal either connected via ssh or directly on the web server and put in

You should get something like:

The first two are search engines. The last one is a machine in Japan. “Get /” is requesting the root page (http://www.cruzit.com/). The “200” is the “OK” code back to the browser. They were served up the index page.

An invaluable tool when writing php code is to use the same command with the error log.

Note: Logging errors needs to be turned on in your php.ini file. For Ubuntu it should be in /etc/php5/apache2/php.ini
Look for the section under “Error handling and logging “ and turn on logging with “log_errors = On”

With newer distributions, you can now tail more than one file at the same time. Try this and enjoy!

Note: Your apache logs may be somewhere else. If you are not running your own server, it may be in your /home directory somewhere.