March 5, 2002
Practical Aspects of Modern Cryptography
70
NATs Rewrite Address/Port Pairs
TCPIP.SYS
Kernel
User
10.0.0.2, 1185, 23
=172.31.249.14
10.0.0.2
131.107.1.7
D
S
IPNAT.SYS
10.0.0.2
131.107.1.7
D
S
10.0.0.2
131.107.1.7
D
S
172.31.249.14
131.107.1.7
D
S
172.31.249.14
131.107.1.7
D
S
10.0.0.3, 1185, 23
=172.31.249.14
Translation
Table
Kernel mode
firewall hook