embodiment shown in fig2 the security driver is an ipsec driver 72 the host computer 70 on which the ipsec driver resides is connected to an external network 76 such as the internet and communicates with other computers on the external network by sending and receiving packets based on the internet protocol the host computer 70 may be a stand alone computer as is the case for most home computers alternatively the host computer may also be part of an internal network 78 such as a local area network u201c lan u201d as in the embodiment shown in fig2 in the illustrated embodiment the host computer 70 functions as a firewall or gateway for computers on the internal network 78 to communicate with computers on the external network 76 for example a computer 80 on the internal network may attempt to communicate with a computer 82 on the external network by transmitting communication packets the packets 84 sent by the computer 80 are transmitted to the gateway computer 70 the ipsec driver 72 of the gateway computer then applies security policies and performs security services under the ipsec protocols to ensure secured delivery of the packets in another scenario the network communication packets may be generated by or destined to an application on the host computer on which the.