AuthLite Interactive Documentation
FEATURES: What can AuthLite Do? TOKEN TYPES: What "Factors" are supported? INSTALL: How and where to install AuthLite? CONFIGURE AuthLite for your needs CHOOSE USERS: Choose 2-factor Users ENFORCE 2-factor Logons ADMINISTER AuthLite Tokens LDAP logon support/enforcement VPN and RADIUS Configuration How to Log In Event Logging

YubiKeys are ideal for any use case where the computer will have a USB port.  Offline logons to laptops disconnected from the LAN work most easily with YubiKeys as well.

Google Authenticator (or other soft token app) is a great choice if you need to save money on the cost of tokens for some users, or if you need to authenticate at systems where a USB port is not available.

When neither of these options is appropriate (no USB devices allowed, no smart phones allowed) you can use a battery-powered LCD displaying OATH token