Can I use the 2 physical NICs in my proxmox host for a web proxy setup?

[alenguav]

My host server has 2 eternet cards and I currently use only of them at this time,
so I was wondering if I could install PfSense or other Linux distro that could help me
to create a proxy server and use both cards for that purpose, just like in this picture
https://www.lucidchart.com/documents/view/612258cd-86b9-4e96-b9cd-a504f0610d69

 

[pirateghost]

Virtualizing routers is quite common. Not sure I understand what you are asking because of course you can have and use a number of interfaces and do what you like with them.