Filter and Firewall
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OmniAccess 5740 Unified Services Gateway CLI Configuration Guide
Alcatel-Lucent
SYN A
TTACK
Knowing traffic pattern for the site helps in preventing this type of attack. For a e-
business site, it may be 20,000 syn packets/second. For a smaller site, it might be
20 syn packets/sec.
Hence, depending upon the traffic pattern, the threshold can be set. If the
threshold is crossed, it might be pointer to a syn attack. One can configure the
threshold as:
ALU(config-firewall)# attack p1
ALU(config-firewall-attack-p1)# tcp-syn-flood threshold 40
1000
P
ORT SCAN ATTACKS
This attacks happens whereby one source IP address sends IP packets to 10
different ports at the same destination IP address within a defined interval. This
again can be prevented by setting a threshold (5 milliseconds is the default). This
can be configured as:
ALU(config-firewall)# attack p1
ALU(config-firewall-attack-p1)# port-scan threshold 10 1000
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