Blocking Mozilla networks is preventing Firefox from accessing other sites.

[securityconscious]

I have blocked two Mozilla networks, one is powered by Amazon Cloud and the other, Cloudflare. Despite this, Mozilla is opening, I tried pinging IP addresses in those networks and I wasn't getting any replies. So, I'm confused why this is happening.

And, when these two Mozilla networks are blocked, many sites are not opening in Firefox(I haven't tried other browsers), when I unblock those networks, those sites are opening. I've checked the IPs of the sites, and they are not in the blocked network. Is this because of some telemetry in Firefox?

[lfirewall1243]

Can you do a NSLookup and Ping on these Sites?

[8191]

Hi,
Firefox checks websites you browse for malicious URLs. I assume the list is hosted within that CDN and Firefox therefore blocks the access.

[securityconscious]

Can you do a NSLookup and Ping on these Sites?

When I NSLookup for mozilla.org, it showed the same 3 IPs which are in the network I have blocked. Do I need to block the nameservers as well?

Other sites are not in those networks, I think the person who posted below probably has the correct reason.

[securityconscious]

Hi,
Firefox checks websites you browse for malicious URLs. I assume the list is hosted within that CDN and Firefox therefore blocks the access.

So this is their politically correct reason for telemetry.