apt-get install libapache-mod-security

Create the folder for the mod-security configuration files

mkdir /etc/apache2/mod-security
chmod 600 /etc/apache2/mod-security

Download and unpack the mod-security rules

cd /tmp
wget http://www.modsecurity.org/download/modsecurity-core-rules_2.5-1.6.1.tar.gz
tar fvx modsecurity-core-rules_2.5-1.6.1.tar.gz
mv *.conf /etc/apache2/mod-security/
ln -s /var/log/apache2 /etc/apache2/logs

Configure apache to load the activated mod-security rules

vi /etc/apache2/conf.d/mod-security.conf

Include /etc/apache2/mod-security/*.conf

To enable mod-security, edit the file

vi /etc/apache2/mod-security/modsecurity_crs_10_config.conf

and remove the # in front of the line:

SecDefaultAction “phase:2,log,deny,status:403,t:lowercase,t:replaceNulls,t:compressWhitespace”

Then reload apache.

/etc/init.d/apache2 force-reload

Mod security will now start to block hack attempts to your websites and log the actions in the file /var/log/apache2/modsec_audit.log.

tail /var/log/apache2/modsec_audit.log

You will see very likely some falsely blocked URL’s. To whitelist them, you can add the ID’s of the rules that should not be used in the whitelist file.

Example:

vi /etc/apache2/mod-security/modsecurity_crs_99_whitelist.conf

SecRuleRemoveById 960015
SecRuleRemoveById 960016

 413 Request Entity Too Large

The configuration variable for this option is “client_max_body_size” and it can be set in the http, server and location sections of the nginx configuration file. To set the Limit globally to 25 MB, edit the nginx.conf file and add:

client_max_body_size 20M;

in the http section.

Example for Ubuntu Linux:

user www-data;
worker_processes 4;
pid /var/run/nginx.pid;

events {
        worker_connections 768;
        # multi_accept on;
}

http {
        geoip_country  /etc/nginx/geoip/GeoIP.dat; # the country IP database
        geoip_city     /etc/nginx/geoip/GeoLiteCity.dat; # the city IP database
        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;

        client_max_body_size 20M;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;
        gzip_disable "msie6";

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}

In Detail:

• Reject sender hostnames with invalid syntax
• Reject sender hostnames that are no fully qualified domains (e.g. reject “server1″ but allow server1.domain.tld)
• Reject sender domains that have no DNS records
• Check sender IP addresses against realtime blacklists.

First make a backup of the postfix main.cf file in case that you want to reverse the changes later:

cp -pf /etc/postfix/main.cf /etc/postfix/main.cf.bak

Then execute this command to enable the additional spam protection functions (the command is one line!).

postconf -e ‘smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_invalid_hostname, reject_non_fqdn_hostname, reject_unknown_recipient_domain, reject_non_fqdn_recipient, reject_unauth_destination, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_rbl_client cbl.abuseat.org,reject_rbl_client dul.dnsbl.sorbs.net,reject_rbl_client ix.dnsbl.manitu.net, check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf, reject_unauth_destination’

Then restart postfix:

/etc/init.d/postfix restart

The message has this format:

————————————————————————
From: ISPConfig <postmaster@localhost.localdomain>
Subject: Welcome to your new email account.

Welcome to your new email account. Your webmaster.
————————————————————————

The first line starts with “From: ” followed by the sender email address. The second line starts with “Subject: ” followed by the email subject. The third line should be empty. All following lines are the email text.

The email text files are named “welcome_email_<language>.txt” where <language> has to be replaced with the system language like “en” for English or “de” for German language, e.g. “welcome_email_en.txt” for the english welcome email.

The customized language file should be stored in the folder /usr/local/ispconfig/server/conf-custom/mail/ so that it does not get overwritten by ISPConfig updates.

Error Opening file /usr/share/GeoIP/GeoIP.dat

The solution is to install the missing package manually:

apt-get install geoip-database

Edit the postfix main.cf file:

vi /etc/postfix/main.cf

and add the line:

smtp_bind_address = 192.168.0.1

were 192.168.0.1 has to be replaced with the primary IP address of the server. Then restart postfix:

/etc/init.d/postfix restart

postfix/master[5309]: fatal: 0.0.0.0:smtps: Servname not supported for ai_socktype

On a OpenSuSE server when you enable smtps in postfix master.cf file. The reason for the error is that the definition of the smtps port in /etc/services is missing.

Solution

Edit the /etc/services file

vi /etc/services

and add the following lines:

smtps 465/tcp # Secure SMTP
smtps 465/udp # Secure SMTP

Then restart postfix

/etc/init.d/postfix restart

ssh root@192.168.0.110

Enter the target SSH-Server’s root password afterwards. To exit the server’s shell, enter

exit

The following rewrite rules can be added into a .htaccess file in the website directory or in the vhost configuration.

RewriteEngine on
RewriteRule ^olddir/(.*)$ newdir/$1 [R=301,L]

This rewrite rule redirects automatically all requests to pages or subdirectorys of “olddir” to the same page or subdirectory in “newdir”.

On Linux systems there are two shell utilitys available to set the I/O and CPU Scheduling for a appliaction or script. The utilitys are named nice and ionice.

Reduce the I/O priority of the script “/usr/local/bin/backup.sh” so that it does not disrupt other processes:

/usr/bin/ionice -c2 -n7 /usr/local/bin/backup.sh

The -n parameter must be between 0 and 7, where lower numbers mean higher priority.

To reduce the CPU priority, use the command nice:

/usr/bin/nice -n 19 /usr/local/bin/backup.sh

The -n parameter can range from -20 to 19, where lower numbers mean higher priority

Nice and ionice can also be combined, to run a script at low I/O and CPU priority:

/usr/bin/nice -n 19 /usr/bin/ionice -c2 -n7 /usr/local/bin/backup.sh