The Apache Software Foundation officially released the Apache 2.4 today as the first major update to this leading open-source web-server in more than a half-decade. Apache 2.4 is slated to deliver superior performance to its 2.2 predecessor and better compete with the growingly-popular NGINX web-server.

Besides much faster performance, among the many enhancements to the Apache 2.4 HTTP Server is better a-synchronous support in its core, run-time loadable MPMs, reduced memory usage compared to Apache 2.2.x, several new modules, enhancements to existing modules, and much more.

Apache HTTP Server 2.4 provides a number of improvements and enhancements over the 2.2 version.
List here:   http://httpd.apache.org/docs/2.4/new_features_2_4.html

You can download Apache HTTP Server 2.4.1 from:  http://httpd.apache.org/download.cgi

Apache 2.4 comes with new modules like:

mod_proxy_fcgi

mod_proxy_scgi

mod_proxy_express

mod_remoteip

mod_heartmonitor, mod_lbmethod_heartbeat

mod_proxy_html

mod_sed

mod_auth_form

mod_session

mod_allowmethods

mod_lua

mod_log_debug

mod_buffer

mod_data

mod_ratelimit

mod_request

mod_reflector

mod_slotmem_shm

mod_xml2enc

More info here: http://www.apache.org/dist/httpd/Announcement2.4.html

If you have received this error while you were restarting the Apache2 server on Debian Squeeze:

/etc/init.d/apache2 start
Starting web server: apache2apache2: Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName

To fix this problem  you need to edit the /etc/apache2/apache2.conf.

1. Open the /etc/apache2/apache2.conf file with your favorite editor.

vim /etc/apache2/apache2.conf

2. Now add the following line:

ServerName localhost

 /etc/init.d/apache2 restart
Restarting web server: apache2 … waiting ..

Use the following command:

apache2ctl -M

The output will look like this:

root@debian:~# apache2ctl -M
Loaded Modules:
core_module (static)
log_config_module (static)
logio_module (static)
mpm_worker_module (static)
http_module (static)
so_module (static)
actions_module (shared)
alias_module (shared)
auth_basic_module (shared)
authn_file_module (shared)
authz_default_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cgi_module (shared)
cgid_module (shared)
deflate_module (shared)
dir_module (shared)
env_module (shared)
mime_module (shared)
negotiation_module (shared)
reqtimeout_module (shared)
rewrite_module (shared)
rpaf_module (shared)
setenvif_module (shared)
status_module (shared)
Syntax OK
root@debian:~#

If you have tons of entries like this in apache2 log and you want to get rig of them:

127.0.0.1 – - [07/Feb/2012:02:56:15 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:16 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:17 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:07 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:20 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:21 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:22 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”
127.0.0.1 – - [07/Feb/2012:02:56:23 +0200] “OPTIONS * HTTP/1.0″ 200 152 “-” “Apache/2.2.16 (Debian) (internal dummy connection)”

Here is how to remove them.:

Step1. Edit /etc/apache2/apache2.conf:

vim /etc/apache2/apache2.conf

Here we will create a filter called local or any other name you want:

Here is how to change from apache2-mpm-prefork to apache2-mpm-worker, , when having used mpm-prefork before, and php5, on Debian Squeeze.

Step1. Stop Apache2:

# /etc/init.d/apache2 stop

Step2. Install apache2-mpm-worker:
That will remove some packages, like apache2-mpm-prefork and libapache-mod-php5, and install apache2-mpm-worker, and php5-cgi instead.

# apt-get install apache2-mpm-worker

Step3. Set Apache2 to use php5-cgi: