Should You Ignore Ping Packets from a WAN Port?

The decision to ignore or allow ping packets from a WAN port in your network infrastructure is a critical consideration that involves balancing security, network performance, and policy compliance. Understanding the implications of these factors is essential for making an informed decision.

Security Concerns

The primary security concern associated with allowing ping packets is their potential use in reconnaissance attacks. ICMP Echo Requests, which form the basis of ping packets, can reveal information about active devices on a network. By ignoring or blocking these packets, you can reduce your attack surface, making it more difficult for attackers to gather valuable information.

Network Performance

Allowing an unnecessary amount of ping requests can impact network performance. Bandwidth is a finite resource, and every packet represents a small but measurable amount of network consumption. In high-traffic environments, ignoring ping packets can help alleviate congestion and ensure that bandwidth is allocated efficiently for more critical communications.

Policy Compliance

Several organizational policies may mandate the filtering of ICMP requests for external sources. This can help reduce exposure and minimize potential vulnerabilities. However, policies and security requirements can vary significantly, so it's crucial to align these decisions with your specific security posture and compliance needs.

Allowing Ping Packets

There are scenarios where allowing ping packets can be beneficial, especially for network troubleshooting and service monitoring. Ping responses can be crucial for diagnosing network connectivity, monitoring the availability of external resources, and ensuring the proper functioning of certain applications or protocols.

Best Practices

To strike a balance between security and network performance, consider the following best practices:

Implement Filtering: Configure your firewall to selectively allow or block ICMP packets based on your specific needs. Rate Limiting: If you do choose to allow ping packets, consider implementing rate limiting to prevent potential abuse. Logging: Maintain logs of ping requests to monitor for any unusual activity and ensure that your network remains secure.

Conclusion

Evaluating your security posture, network requirements, and organizational policies is essential to determine whether to ignore or allow ping packets from a WAN port. Balancing these factors can help you achieve a secure and performant network environment. For some use cases, whitelisting specific ICMP packets, such as allowing ping to EBGP neighbors for WAN segment testing, can be beneficial. However, blindly filtering away all ping packets can sometimes break path MTU negotiation, which is critical for network communication.

Additional Considerations

If you are specifically dealing with ping packets from the Internet to your WAN port, it's worth considering the security benefits of ignoring them. By doing so, you can shield your router from being probed by malicious bots, reducing the risk of unauthorized access and vulnerabilities being exploited.