Paul wrote:
Toast wrote:
I cannot get to login.yahoo.com on my Win 10 1809 computer (or earlier
versions of W10). This is true on IE, Edge, Firefox, Opera, and even
lynx. If I plug my XP computer into my internet connection at home,
it works fine getting to the login page.

I have to use a proxy to get to and past the login page in Win 10.
Once logged in, and at mail.yahoo.com, I can turn off the proxy and it
works fine. I can get to sports.yahoo.com, search.yahoo.com, and other
*.yahoo.com pages without a proxy.

The hosts file, with no *.yahoo.com addresses in it, or giving an IP
number that nslookup returns for login.yahoo.com, does nothing.

Changing resolv.conf does nothing. Changing to use DNS over HTTPS in
Firefox does nothing. Going to Network Connections - right click -
Internet Protocol Version 4 (TCP/IPv4) properties and changing from
obtain DNS address automatically to typing in IP numbers of various
DNS servers does nothing.

I can go to another home/apartment and use their Wi-Fi, and my
computer doesn't work there either. If I use my computer as a Wi-Fi
hot spot, and connect my phone to the computer, I can use yahoo's
email app without any problems.

Any ideas? This has been driving me crazy for over a year with no
resolution. TIA.

Also, logins use https. And a server can demand that the
client use very specific crypto (CHACHA20). Maybe they
set their end to TLS 1.3 and CHACHA20, so that only
Chrome works.

You can test for that, via SSLLabs.

One link tests your browser. The other link, you
enter the server name, for a server evaluation.
Then, compare the two crypto suites printed out,
to see if they share a common entry or twenty.
Servers with a very short crypto suite list, will
make this relatively easy to figure out.

https://www.ssllabs.com/ssltest/viewMyClient.html

https://www.ssllabs.com/ssltest/

Paul