Patton electronic SmartNode 4110 Series ユーザーズマニュアル

Introduction

SmartWare Software Configuration Guide 

Figure 17. Dynamic NAPT

Dynamic NAPT does not permit hosts on the global network to access hosts on the local network. Static 
NAPT makes selected services (i.e. ports) of local hosts globally accessible. Static NAPT entries map global 
addresses/ports to local addresses/ports. The global address can either be the address of the global interface or a 
configured global NAPT address. Usually, the local and the global port of a static NAPT entry are the same; 
however, they may be different.

Figure 18. Static NAPT

Be careful when mapping ports the SmartNode uses itself (e.g. Telnet, 
TFTP) because the SmartNode might become inaccessible.

NAT only modifies addresses but not ports. Dynamic NAT assigns a global address from a global NAT address 
pool each time a local host wants to access the global network. It creates a dynamic NAT entry for the reverse 
path. If a connection is idle for some time (2 minutes), the dynamic NAT entry is removed. Should Dynamic 
NAT run out of global addresses, it lets Dynamic NAPT handle the connection (which may lead to an unex-
pected behavior).

131.1.1.1 (Global Interface Address)
131.1.1.10 - 131.1.1.15 (Global NAT Address Pool)

192.168.1.30 - 192.168.1.39

Source Address modified

Destination Address modified

LAN

(Local Interface Address) 192.168.1.1

192.168.1.20:80

192.168.1.20:23

Source Address modified

Destination Address modified

LAN

(Local Interface Address) 192.168.1.1