Intermittent problems connecting to websites

I’ve been using Comodo Secure DNS for years but last couple of days some websites would not connect. Browser would give a “temporarily not available” error while the website indeed was available when I tried to connect via mobile network (which obviously doesn’t use Secure DNS).

I tried to find some info on here and noticed that Secure DNS IPs were changed from / to / I then changed to the latter 2 IPs and the sites in question were reachable again.

Now I have 3 questions:

  1. Why did the IP addresses for Comodo Secure DNS change?
  2. It seems the old addresses still work (at least, for the most part). Why didn’t Comodo announce the change?
  3. Why is there a difference in service between the old and new DNS addresses?

Hi Stephan,

Thanks for the questions. The latter two IPs belong to the new SecureDNS network.

The reasons for the new network include overall stability, speed, and security improvements, as well as incorporating the new customizable user control panel which is in limited (beta) release.

While a formal announcement has yet to be made, the new service was announced on the forums in this post. I believe the update was also mentioned in software updates to Comodo Dragon and other systems that include SecureDNS as an option.

The new IPs were updated on the original page at Free Comodo Secure DNS | Best DNS Security Solution 2022 and the new page

The difference in service is due to the new network being run on a completely separate infrastructure from the original network.

I don’t have any details on how long the original IPs will continue to be available but we are encouraging everyone to migrate to the new IPs. You can be sure we will provide more information as the final rollout happens.

We hope you like the new network and we certainly welcome all feedback!