Alcatel-Lucent OmniAccess 5740 - Tcp-Invalid-Urgent-Offset; Tcp-Null-Scan

Filter and Firewall
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OmniAccess 5740 Unified Services Gateway CLI Command Reference Guide
Alcatel-Lucent
TCP-INVALID-URGENT-OFFSET
tcp-invalid-urgent-offset
DESCRIPTION
This command is entered in the Firewall-Attack Sub Configuration Mode. The
intruder sends a TCP frame with an Urgent pointer which points past the end of
the data. This may cause some TCP/IP implementations to become unstable or
crash. Some TCP/IP implementations will hang when receiving many such
frames.
PARAMETERS
None.
EXAMPLE
ALU(config-firewall-attack-A1)# tcp-invalid-urgent-offset
TCP-NULL-SCAN
tcp-null-scan
DESCRIPTION
This command is entered in the Firewall-Attack Sub Configuration Mode. TCP
packets without any flag set. Leads to inability to scan such packets. This attack
can also be avoided by including this command in the user-defined prevention list
or by the “default” keyword.
PARAMETERS
None.
EXAMPLE
ALU(config-firewall-attack-A1)# tcp-null-scan