Google Public DNS, with its well-known IP address 8.8.8.8 and 8.8.4.4, is widely used for DNS resolution due to its reliability and speed. However, there are instances where this IP address might be flagged as a port scanner and subsequently listed in firewall deny lists. Here are some reasons why this might happen:
- High Volume of Requests: Google Public DNS handles a massive number of DNS queries from users worldwide. This high volume of traffic can sometimes be misinterpreted by security systems as suspicious activity, such as port scanning.
- Shared IP Usage: The IP address 8.8.8.8 is used by many different users and systems. If any of these users engage in activities that resemble port scanning, the IP address can be flagged, affecting all users of the service.
- Misconfigured Systems: Sometimes, misconfigured systems or applications might inadvertently send out requests that resemble port scanning. Since these requests are routed through Google Public DNS, the IP address can be mistakenly identified as the source of the scan.
- Security Precautions: Firewalls and security systems are designed to be cautious. They might flag any unusual or unexpected traffic patterns, even if they originate from a trusted source like Google Public DNS, to prevent potential security threats.
- False Positives: Security tools are not infallible and can sometimes generate false positives. This means legitimate traffic from Google Public DNS might be incorrectly identified as malicious activity.
It’s important to note that this is a good sign that your firewall is working fine. However, after some time, you should erase that IP from your deny list. It’s possible that someone is spoofing the IP address, and you wouldn’t want to block legitimate traffic unnecessarily.
While Google Public DNS is generally safe to use and trusted by many, it’s important to monitor and configure your security settings to ensure that legitimate services are not inadvertently blocked. If you encounter such issues, reviewing your firewall rules and consulting with network security experts can help mitigate these false positives.