Do you mean that an account can have only ONE session open? The answer is yes, this is exactly what the plug-in is about and the Standard Edition (freeware) will already do this for you. Please clarify if this is not what you mean.
Second question: one account from one IP only. The Business Edition has the option to "lock" the IP address. This means that when a user logs in from a certain IP, he/she cannot log in from a different IP during some period (period can be configured from 5 minutes up to 1 month max). Please note that IP addresses can be faked (spoofed) and an account can be 'hijacked' if malicious user logs into account from some IP, the legitimate account holder may not be able to log in from his/her IP during X period.
