Whether the HTTP port (port 80) should be open depends entirely on the network's purpose and security needs. It's not a simple yes or no answer.
In most networks, outgoing traffic on port 80 needs to be open for users to access websites. Any web server that is accessible from the internet almost always requires port 80 to be open for incoming traffic. However, opening any port introduces potential security risks.
Outgoing vs. Incoming Traffic
- Outgoing (Client Requests): Users on a network need to be able to send requests to web servers on the internet. Closing port 80 for outgoing traffic would prevent them from accessing most websites.
- Incoming (Server Responses): Web servers must listen for incoming connections on port 80 (or 443 for HTTPS). If port 80 is closed to incoming traffic, the web server cannot serve web pages.
Risk Mitigation
While opening port 80 does present risks, these can be significantly mitigated:
- Firewall Rules: Implement strict firewall rules to allow only necessary traffic.
- Intrusion Detection/Prevention Systems (IDS/IPS): Monitor traffic for malicious activity and block suspicious connections.
- Regular Security Audits: Regularly assess the security posture of the network and servers.
- Keep Software Updated: Regularly update web servers and associated software to patch security vulnerabilities.
- Consider HTTPS: Whenever possible, use HTTPS (port 443) instead of HTTP (port 80). HTTPS encrypts the traffic, making it more secure. You can configure your webserver to redirect all HTTP requests to HTTPS.
When to Consider Closing Port 80
There are specific scenarios where closing port 80 might be appropriate:
- Internal Networks with No Web Server: If a network is entirely internal and does not host any web servers accessible from the outside, closing port 80 for incoming traffic can reduce the attack surface.
- Web Server Using Only HTTPS: If a web server is configured to use HTTPS exclusively and redirects all HTTP traffic to HTTPS, then technically port 80 can be closed. However, many admins leave it open with a redirect, due to client configuration issues.
Summary
Generally, port 80 is a necessary evil, especially for web servers. While it introduces risk, proper security management practices can significantly reduce the chances of exploitation. The key is to understand the traffic flow, implement strong security controls, and continually monitor for vulnerabilities.
