Cisco pix 501 vs 501-50

10 vs 50 users

I'm not sure on the VPN, never used it. It is actually concurrent connections to the Internet. You get 10 unique internal IP's and then the next client gets denied. You can clear xlate to start the count over again. It's a pain unless you are a very small network.

10 license gives you 10 outbound connections to the internet and 10 vpn connections.

That's close, but the details are more complex. And one important point to note is that internal IPs -usually- time out of the count when the IP stops using the network.

For more details on what actually happens, see