I can't reach
github.com; the DNS resolves but then the connection times out (on Safari, Firefox and Chrome). I'm running macOS 10.15.5.
sudo dscacheutil -flushcache and
sudo killall -HUP mDNSResponder, to no avail.
See this superuser question for all the debugging I've done so far
I'm asking a separate question here because one key clue is that when logging in with my laptop's guest account, I can reach github.com. If I create another admin user account however, the issue is still there.
For that reason I'm wondering: what are the networking-related settings that would apply to regular users but not the guest account?
Edit Adding more debugging info
digoutput showing that DNS resolves:
$ dig github.com ; <<>> DiG 9.10.6 <<>> github.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54977 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;github.com. IN A ;; ANSWER SECTION: github.com. 59 IN A 22.214.171.124 ;; Query time: 109 msec ;; SERVER: 126.96.36.199#53(188.8.131.52) ;; WHEN: Tue Jun 09 22:07:32 CEST 2020 ;; MSG SIZE rcvd: 55
- Request timing out in
$ curl -v --insecure -L 184.108.40.206 * Trying 220.127.116.11... * TCP_NODELAY set * Connected to 18.104.22.168 (22.214.171.124) port 80 (#0) > GET / HTTP/1.1 > Host: 126.96.36.199 > User-Agent: curl/7.64.1 > Accept: */* > < HTTP/1.1 301 Moved Permanently < Content-length: 0 < Location: https://188.8.131.52/ < * Connection #0 to host 184.108.40.206 left intact * Issue another request to this URL: 'https://220.127.116.11/' * Trying 18.104.22.168... * TCP_NODELAY set * Connected to 22.214.171.124 (126.96.36.199) port 443 (#1) * ALPN, offering h2 * ALPN, offering http/1.1 * successfully set certificate verify locations: * CAfile: /etc/ssl/cert.pem CApath: none [...TLS handshake details] * TLSv1.2 (IN), TLS handshake, Finished (20): * SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256 * ALPN, server accepted to use http/1.1 * Server certificate: * subject: C=US; ST=California; L=San Francisco; O=GitHub, Inc.; CN=github.com * start date: May 5 00:00:00 2020 GMT * expire date: May 10 12:00:00 2022 GMT * issuer: C=US; O=DigiCert Inc; OU=www.digicert.com; CN=DigiCert SHA2 High Assurance Server CA * SSL certificate verify ok. > GET / HTTP/1.1 > Host: 188.8.131.52 > User-Agent: curl/7.64.1 > Accept: */* > < HTTP/1.1 301 Moved Permanently < Content-length: 0 < Location: https://github.com/ < * Connection #1 to host 184.108.40.206 left intact * Issue another request to this URL: 'https://github.com/' * Trying 220.127.116.11... * TCP_NODELAY set * Connection failed * connect to 18.104.22.168 port 443 failed: Operation timed out * Failed to connect to github.com port 443: Operation timed out * Closing connection 2 curl: (7) Failed to connect to github.com port 443: Operation timed out * Closing connection 0 * Closing connection 1
If I curl without
-L (i.e. without redirects) then I do get to the site, and get the HTML back:
$ curl -H "Host: github.com" --insecure -v https://22.214.171.124/ ... < HTTP/1.1 200 OK <!DOCTYPE html> <html lang="en"> ...