Telematics Chapter 6: Network Layer - Freie Universität Berlin

NAT Variants
● NAT is available in several “variants”, known under different names
● Basic NAT (also: Static NAT)
● Each private IP address is translated into one certain external IP address
● Either, you need as much external addresses as private ones, otherwise no retranslation
is possible when a reply arrives
● Or, you manage a pool of external IP addresses and assign one dynamically when a
request is sent out
192.168.0.2 192.168.0.3
Server
Computer
Computer
Ethernet
Computer
192.168.0.4 192.168.0.5
Private IP Map to
192.168.0.2 147.216.13.32
192.168.0.3 147.216.13.33
192.168.0.4 147.216.13.34
192.168.0.5 147.216.13.35
router with
NAT box
Internet
192.168.0.2 192.168.0.3
Server
Computer
Computer
Ethernet
Computer
192.168.0.4 192.168.0.5
Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 6: Network Layer
Private IP Currently
mapped:
192.168.0.2 147.216.13.32
192.168.0.5 147.216.13.33
--- 147.216.13.34
--- 147.216.13.35
router with
NAT box
Internet
6.88