On my laptop i do:
openssl s_client -connect w00d8dd4.kasserver.com:465
I can see that the connection works. I can also do :
telnet w00d8dd4.kasserver.com 465
Also no problem.
Now, if I log in to my cloud server - and run the same command(s) as above - such as:
openssl s_client -connect w00d8dd4.kasserver.com:465
Then there is NO output, nothing happens even after several seconds.
However, if I do :
openssl s_client -connect kyle.com:443 -showcerts
it immediately connects. I have also tested with -tls1 and -debug switches. There is no difference.
I believe, this might be due to certain outgoing connection being blocked by firewall. How can I debug?
I have seen this question - but I was not able to find a proper guide. I have installed ca-certificates (20211016ubuntu0.22.04.1). The cloud serve is running UBuntu :
uname -a says :
Linux myStep-ubuntu-4gb-nbg1-2 5.15.0-67-generic #74-Ubuntu SMP Wed Feb 22 14:14:39 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
UPDATE
I have tried tcptraceroute -p 465 w00d8dd4.kasserver.com
from the could server. It finds a route to the target, the result is:
1 172.31.1.1 6.736 ms 5.755 ms 5.271 ms
2 17332.your-cloud.host (49.12.141.110) 0.447 ms 0.311 ms 0.280 ms
3 * * *
4 static.173.0.47.78.clients.your-server.de (78.47.0.173) 1.230 ms 0.834 ms 0.914 ms
5 spine12.cloud1.nbg1.hetzner.com (78.47.3.45) 16.399 ms 0.911 ms 1.044 ms
6 213-239-239-141.clients.your-server.de (213.239.239.141) 1.003 ms 0.515 ms 0.701 ms
7 core0.fra.hetzner.com (213.239.252.25) 3.715 ms 3.788 ms 3.842 ms
8 ipv4.de-cix.fra.de.as34788.all-inkl.com (80.81.192.119) 21.491 ms 21.468 ms 21.351 ms
9 dd5114.kasserver.com (85.13.130.50) [open] 21.720 ms 21.228 ms 21.275 ms