Security as a condition is the degree of resistance to, or protection from, harm. It applies to any vulnerable and valuable asset, such as a person, dwelling, community, nation, or organization. Establishing or maintaining a sufficient degree of security is the aim of the work, structures, and processes called “security.”

Wikipedia

Contents

1 Here are some best practice
- 1.1 For you server
- 1.2 For your applications
2 Backup your data

Here are some best practice

For you server

Firewall : You must close ALL ports except the ones you need. If possible restrict the access to a list of IP adress.
ICMP : Configure your server to not answer to ping requests.
Passwords
- change default passwords for all your applications (specially some visible from outside!)
- use strongs passwords

For your applications

Apache server : user Proxypass to expose only url you choose.

Backup your data

Mysql

Look here

Rsync

rsync -r -t -p -v -h -b --progress --delete --force --filter "- mydirectory1" --filter "- mydirectory2" --filter "- myFile1" --suffix .rsync-backup /etc/directoryToBackup/ /opt/backup

lftp (sync to a ftp server)

Create file.lftp:

# open connection:
open login:pwd@myftpserver
 
# syncronize with remote:
# directoryToSend : relative working directory path
# www/project : relative remote directory path to sync.
# Options are : 
#    -v       : verbose
#    -R       : Reverse (from working copy to remote)
#    -e       : remove missing files in remote
#  --no-perms : skip changing permissions
#  --exclude  : exclude pattern to sync.
#
mirror "/mylocal/directory" my/ftp/directory -v -R -e --no-perms --exclude .tmp

lftp -f ./file.lftp

sql server

echo install Node.js package manager
yum -y install npm
 
echo install Cross platform command line interface for SQL Server
npm install sql-cli

Now you can use it like this:

mssql --server myserver --user myuser --pass mypassword --database mydatabase

My linux world

Security-commons Survival Guide

Here are some best practice

For you server

For your applications

Backup your data

Mysql

Rsync

lftp (sync to a ftp server)

sql server