10 tips to improve computer network security

1. Apply all security patches to software,continuously.
   
2. Harden passwords. Make users create passwords that are at least 8 characters with upper and lower case characters, numbers and punctuations.
   
3. Harden systems. Turn off unnecessary services and lock down shares.
   
4. Harden firewall rules. Stop unnecessary outbound traffic and close unneeded ports.
   
5. Implement an SMTP (mail server) proxy and filter out dangerous attachments.
   
6. Secure VPN users with personal firewalls.
   
7. Audit users. Systematically go through your user accounts, and make sure people don't have access or rights they should not have.
   
8. Build redundancy into your network in case of failure. Implement and test your disaster recovery plan.
   
9. Outsource web servers or lock them down.
   
10. Outsource security audits to specialised security service providers if your core business isn't security.