Hardware client is substitute to vpn client software, vpn client software needs to be installed in every client machine, hardware client can be used in SOHO environment for a few client machines to connect, you will not need VPN client software on these machines. VPN Clients are required to connect to vpn server.
VPN concentrator is VPN server which can provide VPN services like IPSEC, PPTP, WEBVPN, SSL.
For more information on VPN you can check this nice brief link:
Besides the difference already descibed above an other difference is that a hardware client like the VPN3002 supports only one subnet behind his internal interface while a VPN3005/30xx supports more subnets by adding them to a netowrklist.
Good luck !
PS: by the way, they're end of sale by august 2007
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...