Intel ER8100STUS - Express 8100 Router, Reference Manual

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Reference.bok : Chapter08 55 Wed Apr 22 10:58:08 1998
55
IP Concept
IP Routing
3. If no filter entry is found where all the filter criteria match those of the
packet, the default filter action is used to either pass or discard the packet.
Logging filtered packets
The router allows filtered packets to be logged. This facility can be configured
for both packets filtered by filter entries and packets filtered by the default filter
action. This is a useful tool for troubleshooting the filters to ensure that they are
operating as expected, and for detecting hits on the filters in case of an attack
from an unauthorized source.
Note
Logging reduces the performance of the router slightly and should
therefore only be enabled when required—when troubleshooting or
when an attack is suspected.
For packets which are logged, the packet details are recorded in the System Log
for the router which cabn be displayed for Intel Device View for Windows. The
details logged are the source and destination address and port and the IP protocol.
IP Filter Example
Filter requirement
Host 1 on LAN 1 must have TELNET access to remote Host 2 on LAN 2 (but
Host 2 must not be able to establish a TELNET session onto Host 1).
1231
IP Packet
Pass/
discard Pass
discard Pass/
discard Pass/
discard Pass/
discard Pass/
discard
Filter
1
Filter
2
Filter
3
Filter
N
Default
Action
Host 1
WAN 1 WAN 2
Leased line
LAN 1 LAN 2
Telnet Server
1474
Router 1
Router 2
Host 2
LAN WAN 1 WAN 2 System
® Intel Express Router 9200
LAN WAN 1 WAN 2 System
® Intel Express Router 9200