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̈ Chapter 8: Firewall LANCOM Reference Manual LCOS 3.50
117
Firewall
The LANCOM Firewall uses several lists for checking data packets, which are
automatically generated from Firewall rules, resulting Firewall actions or by
active data connections:
̈ Host block list
̈ Port block list
̈ Connection list
̈ Filter list
When a data packet should be routed via the IP router, the Firewall uses the
lists as follows:
ቢ The first check is, whether the packet was coming from a workstation
belonging to the host block list. If the sender is blocked, the packet will
be discarded.
ባ If the sender is not blocked in this list, the port block list will be checked,
if the used port/protocol combination on the destination PC is closed. In
this case the packet will be discarded.
ቤ If sender and destination are not blocked in the first two lists, then it will
be checked whether a connection entry exists for this packet in the con-
nection list. If such an entry exists, then the packet will be handled as
noted in this list.
ብ If no entry has been found for the packet, then the filter list will be
searched, whether a suitable entry exists and the action indicated in this