Lancom Systems LCOS 3.50 7.3 The hiding placeIP masquerading (NAT, PAT)

LANCOM Reference Manual LCOS 3.50  Chapter 7: Routing and WAN connections

Routing and WAN

connections

assume a certain order that differs from the protocol standard. In this case the

SYN/ACK speedup can be deactivated:

7.3 The hiding place—IP masquerading (NAT, PAT)

One of today's most common tasks for routers is connecting the numerous

workstation computers in a LAN to the network of all networks, the Internet.

Everyone should have the potential to access, for example, the WWW from his

workstation and be able to fetch bang up-to-date information for his work.

IP masquerading provides a hiding place for every computer while connected

with the Internet. Only the router module of the LANCOM and its IP address

are visible on the Internet. The IP address can be fixed or assigned dynamically

by the provider. The computers in the LAN then use the router as a gateway

so that they themselves cannot be detected. Thereby, the router separates

Internet and Intranet.

How does IP masquerading work?

Masquerading makes use of a characteristic of TCP/IP data transmission,

which is to use port numbers for destination and source as well as the source

and destination addresses. When the router receives a data packet for transfer

it now notes the IP address and the sender's port in an internal table. It then

gives the packet its unique IP address and a new port number, which could be

Configuration tool Menu/table

LANconfig IP router  General  Pass on TCP SYN and ACK packets prefer-

entially

WEBconfig Expert Configuration  Setup  IP-router-module 

Routing-method  SYN/ACK-speedup

Termin al/Tel net

cd /setup/IP-router-module/routing-

method set SYN/ACK-speedup OFF