Inexpensive two-factor authentication for a home server?

Question

I was considering adding some kind of two-factor authentication to my small home network of dedicated Linux servers. I will need, maybe, in the absolute majority, 10 physical devices. Are there any companies that will provide such a small order, relatively cheap?

Thanks Daniel

PS This is mainly for my own pleasure in creating the system; I do not pretend to function with a high degree of risk.

Answer 1

Duo Security Unix-: duo_unix. .

, Duo.

Answer 2

- OPIE? (OTP- S/KEY). PAM, , OTP, .