I'm trying to develop a list of candidate two factor authentication solutions for Checkpoint firewall. We have a small group of contractors who need to deal with access to several systems from a remote network. I don't particularly need VPN. I don't need to encrypt the data at more than even the 56-bit level. What I do need to make sure of is that anyone on the contractor's ISP's network who knows his IP, his userid, and his password, cannot get past our firewall. I'm assuming that any decent two factor authentication scheme that is based on tokens would probably be hard enough to get past that it would stop 99% of the possible intrusions. That's good enough.
What two factor authentication solutions are:
1) Compatible with older Checkpoint releases. I believe we have the release prior to Next Generation.2) Are relatively cheap.
If there are solutions available as used product, that would be okay as well.
What are my options?