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Firefox can't find CDC.gov site. Works fine in Safari

  • 7 回覆
  • 1 有這個問題
  • 145 次檢視
  • 最近回覆由 GRobLewis

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I have been trying all day to access the Centers for Disease Control website at cdc.gov. Firefox (83.0/Mac) just says it can't contact the server. I used Network Utility to look up the IP address of the site, which reported 198.246.102.49. I entered that address into Firefox and it refused to go there, saying it was a potential security risk.

So I tried Safari (14.0.1), and cdc.gov loads immediately with no problems.

What the heck?

I have been trying all day to access the Centers for Disease Control website at '''cdc.gov'''. Firefox (83.0/Mac) just says it can't contact the server. I used Network Utility to look up the IP address of the site, which reported 198.246.102.49. I entered that address into Firefox and it refused to go there, saying it was a potential security risk. So I tried Safari (14.0.1), and '''cdc.gov''' loads immediately with no problems. What the heck?

被選擇的解決方法

The difference is that when you use DNS over HTTPS, your address lookups are done on a Cloudflare DNS server instead of your regular DNS server.

As of the time I tested yesterday, that server reported there was no address for www.cdc.gov so the redirect fails. However, it seems fine now.

從原來的回覆中察看解決方案 👍 0

所有回覆 (7)

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I should have noted that Firefox doesn't seem to have trouble with any other websites.

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I had no problem with https://www.cdc.gov/

Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

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Your connection is not secure

The owner of 198.246.102.49 has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

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Not sure when it started, but at the moment, I cannot get to cdc.gov using Cloudflare as my DNS over HTTPS service provider. If I turn off DNS over HTTPS and use my home ISP then Firefox can load the site.

More info on DNS over HTTPS: Firefox DNS-over-HTTPS

There's a hidden research tool in Firefox you can check on this -- type or paste the following internal address into the address bar and press Enter to load it:

about:networking#dnslookuptool

When using Cloudflare, I get an address for cdc.gov but not for www.cdc.gov. Strange!

When I check a third party website, it indicates that www.cdc.gov uses the Akamai content distribution network. Perhaps there is configuration issue somewhere in the server farm.

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Interesting. When I use the Firefox lookup tool for cdc.gov, it gives me the same result as the Mac's Network Utility: 198.246.106.49. Like you, I get an "unknown host" error for www.cdc.gov.

If I simply try to access cdc.gov in Firefox, I get "We can’t connect to the server at www.cdc.gov" (after a redirect to https://www.cdc.gov).

If I paste 198.246.106.49 into the normal Firefox address bar, I get a "Warning: Potential security risk ahead", with this explanation: Websites prove their identity via certificates. Firefox does not trust this site because it uses a certificate that is not valid for 198.246.106.49. The certificate is only valid for the following names: www.cdc.gov, cdc.gov, 4mmp.cdc.gov, dpd.cdc.gov, e-cigarettes.surgeongeneral.gov, flu.gov, knowits.niosh.gov, knowitsniosh.niosh.gov, millionhearts.hhs.gov, origin.cdc.gov, origin.glb.cdc.gov, origin.int-f5.cdc.gov, origin2.cdc.gov, search.cdc.gov, search-origin.cdc.gov, www.dpd.cdc.gov, www.flu.gov, www.millionhearts.hhs.gov, www.selectagents.gov, selectagents.gov, www.thecommunityguide.org, open.cdc.gov Error code: SSL_ERROR_BAD_CERT_DOMAIN (perhaps this is to be expected when trying to load an IP address instead of a domain name)

In Safari on the same Mac, cdc.gov redirects to https://www.cdc.gov and loads immediately with no apparent problems.

On my home LAN I run a Mac with macOS Server, with a DNS for my local machine names. It also serves my personal website, via CloudFlare, but I don't see any reason why this would even be involved in a fetch of an external site like cdc.gov.

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選擇的解決方法

The difference is that when you use DNS over HTTPS, your address lookups are done on a Cloudflare DNS server instead of your regular DNS server.

As of the time I tested yesterday, that server reported there was no address for www.cdc.gov so the redirect fails. However, it seems fine now.

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It works for me now too. I haven't changed anything on my end.