Two free security-focused DNS services. Comodo is smaller but aggressive. OpenDNS is bigger but more conservative.
Comodo Secure DNS (8.26.56.26) is a free DNS service from Comodo, a cybersecurity company known for SSL certificates and antivirus software. It blocks phishing, malware, and spyware domains. OpenDNS (208.67.222.222) is Cisco's free DNS resolver that also blocks malicious domains.
Both are free. Both focus on security. But they are very different in terms of reliability, speed, and how aggressively they block content.
Comodo DNS is aggressive about blocking. It blocks not just phishing and malware, but also domains that Comodo's scanners flag as suspicious. This can lead to false positives. Some legitimate domains get blocked because they use redirects or have content that triggers Comodo's scanners.
OpenDNS is more measured. It blocks known phishing and malware domains using Cisco Talos threat intelligence. False positives are rare. OpenDNS also lets you customize filtering categories if you create a free account.
OpenDNS is faster and more reliable. Comodo DNS has fewer data centers and less consistent performance. In testing, Comodo DNS can be 20-50ms slower than OpenDNS, depending on location. OpenDNS also has better uptime thanks to Cisco's infrastructure.
Comodo logs query data. They state that logs are kept for security purposes but do not specify retention periods clearly. OpenDNS logs data and shares it with Cisco's security team. Neither is strong on privacy compared to Cloudflare or Quad9. If privacy is your main concern, look elsewhere.
Choose Comodo if: You want aggressive blocking. You prefer a smaller company. You are already using other Comodo security products.
Choose OpenDNS if: You want more reliable performance. You want fewer false positives. You want customizable filtering. You want better uptime.
OpenDNS is the better choice for most people. Comodo's aggressive blocking causes too many false positives for general use.