Lancom Systems LCOS 3.50 - Manual (Page 114)

LANCOM Reference Manual LCOS 3.50 ̈ Chapter 8: Firewall
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Application Gateways: It never exists a direct connection e.g. between a client
of the local network and a server of the Internet. The LAN workstations only
see the proxy, the workstations of the Internet likewise. This physical separa-
tion of LAN and WAN, makes it quite difficult for attackers to intrude into the
protected network.
Applied to the porter example, the packet will be left at the gate, the courier
is not allowed to enter the company premises. The porter takes the packet,
will open it after checking address and delivery note and will control also the
content. When the packet has taken these hurdles successfully, then the com-
pany internal courier will bring it himself to the addressee of the company. He
became proxy of the courier on company premises. The other way around, all
employees, wanting to send a packet, have to inform the porter, which has to
collect the packet at the workstation place and which will hand over the
packet to the ordered courier at the gate.
Functions of Application Gateways are not supported by the
LANCOM, mainly because of the high hardware demands.
8.3 The LANCOM Firewall
After general explanations concerning the dangers of the Internet and the
tasks and types of Firewalls, this chapter describes special functions of the
LANCOM Firewall and concrete configurations.