Talking about server side security will come down to firewall or filter connections from and to your server. Close unnecessary ports, block unwanted connection and blacklist spammers are the things that your server admin should do in their everyday life. If you pay attention to your server log, you will found that lot of malicious request and brute force bot attack to find your server vulnerabilities. You should block it with firewall.
One of the good and free Firewall module is ConfigServer Security and Firewall. It have compatibility with most known Linux server and integration with WHM/Cpanel.
Some ConfigServer Security and Firewall features:
- Straight-forward SPI iptables firewall script
- Daemon process that checks for login authentication failures.
- Courier imap, Dovecot, uw-imap, Kerio
- openSSH
- cPanel, WHM, Webmail (cPanel servers only)
- Pure-ftpd, vsftpd, Proftpd
- Password protected web pages (htpasswd)
- Mod_security failures (v1 and v2)
- Suhosin failures
- Exim SMTP AUTH
- Custom login failures with separate log file and regular expression matching
- POP3/IMAP login tracking to enforce logins per hour
- SSH login notification
- SU login notification
- Excessive connection blocking
- UI Integration for cPanel, DirectAdmin and Webmin
- Easy upgrade between versions from within cPanel/WHM, DirectAdmin or Webmin
- Block traffic on unused server IP addresses – helps reduce the risk to your server
- Alert when end-user scripts sending excessive emails per hour – for identifying spamming scripts
- Suspicious process reporting – reports potential exploits running on the server
- Suspicious file reporting – reports potential exploit files in /tmp and similar directories
- Directory and file watching – reports if a watched directory or a file changes
- Block traffic on the DShield Block List and the Spamhaus DROP List
- BOGON packet protection
- Pre-configured settings for Low, Medium or High firewall security (cPanel servers only)
- Works with multiple ethernet devices
- Server Security Check – Performs a basic security and settings check on the server (via cPanel/DirectAdmin/Webmin UI)
- Allow Dynamic DNS IP addresses – always allow your IP address even if it changes whenever you connect to the internet
- Alert sent if server load average remains high for a specified length of time
- mod_security log reporting (if installed)
- Email relay tracking – tracks all email sent through the server and issues alerts for excessive usage (cPanel servers only)
- IDS (Intrusion Detection System) – the last line of detection alerts you to changes to system and application binaries
- SYN Flood protection
- Ping of death protection
- Port Scan tracking and blocking
- Permanent and Temporary (with TTL) IP blocking
- Exploit checks
- Account modification tracking – sends alerts if an account entry is modified, e.g. if the password is changed or the login shell
- Country Code blocking – Allows you to deny or allow access by ISO Country Code
- Port Flooding Detection – Per IP, per Port connection flooding detection and mitigation to help block DOS attacks
Install ConfigServer Security & Firewall:
- Login as root to your server via SSH
- Download CSF:
wget http://www.configserver.com/free/csf.tgz
- Extract it:
tar -xzf csf.tgz
- Install it:
cd csf sh install.sh
The CSF will available under your WHM menu > Plugins > ConfigServer Security&Firewall. As soon as you go to CSF page, check your server security and increase your security point based on what the wizard says. After that configure your Firewall level, i will go to Medium to high setting. And turn on your CSF from Firewall Configuration and set “TESTING” to 0.
cool