Firewall – Web Site Access – Whitelist Porting

I am able to access a certain website from a corporate network (the default https port 443 was allowed in the Windows firewall of the machine

The same company provided a personal PC, and I would like VPN (connect via home WIFI) and can access the same server via RDP.

However, I can not access the website above. Can confirm that I have disabled the proxy settings.

When I informed the security network team of this company, they announced the opening of port 68080 and I can now access this URL.

  1. Where would this second whitelist be done (in general), and why is the whitelist of 443 not enough?

  2. When I access the page via IE, it works well. But receive a warning when I access it via Firefox or Chrome. It warns that the connection is not private. By examining the http certificate, it is indicated that the certificate is correct. However, the signature hash algorithm is SHA-1. When I asked if it was not possible to generate a SHA-256 certificate, they replied that it would involve a lot of work. Is it true? Please also report an article with a clear explanation (high level) of the required changes.

Thanking in advance,
To fart