I am trying to find out if 2012 R2 can connect to a VPN with the following data:
- Phase 1 Proposal: pre-g20-aes256-sha2-256 (86400)
- Phase 2 Proposal: esp-g20-aes256-sha2-256 (4800)
- IKEv1
- PFS enabled
- pre-shared keys
Is that possible? For example, I don't find IKEv1 as an option, only IKEv2, PPTP, L2TP/IPSec, and SSTP.
No, you can only use IKEv2 or L2TP/IPSEC. Here is a guide on how to setup L2TP/IPSEC.
https://www.magnumvpn.com/setup-vpn-windows-10-l2tp-ipsec.html
You might also need to open your windows firewall for it to work.
https://www.magnumvpn.com/setup-windows-10-firewall-l2tp.html
This is not an answer, but as a workaround, you can install VyOS on a virtual machine.
Either on that Windows machine in question itself, or somewhere else. I just did that, and VyOS works like a charm as my VPN router with the above parameters, and many more details like NATting etc that are easy to configure in VyOS. (But VPN site-to-site itself is not easy at all)