Network Security

    
Attacks:
1. TCP/IP Attacks
2. Denial-of-Service Attacks
3. Spoofing attacks
4. Man-in-the-middle data interception and modification attacks

Checklist:
- Place webserver in network separate from production network (DMZ or perimeter network)
- Use separate address space/subnet
- Use secure border devices (firewall, external filtering router) to stop unauthorized access
- Limit inbound/outbound ports and protocols through firewall directed at web server
- Filter IP source addresses allowed to access servers ('blacklist' IPs)
- Whitelist IPs
- Filter applications allowed through firewall to server - limit to http, ssh, etc
- Don't run extraneous apps on server if not necessary(eg: SMTP, ftp, etc...)
- Encrypt authentication data and sensitive data to/from webserver by using SSL, ssh, IPSec, etc to prevent man-in-the-middle attacks
- Keep webserver/application server/database server on separate boxes if possible - use multi-tiered configuration