Linksys SRW224P - Manual (Page 66)

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Chapter 5: Configuring the Switch through the Web Utility
Security
24-Port 10/100 + 2-Port Gigabit Switch with Webview and Power over Ethernet
Protocol. Specifies the protocol type to match as TCP, UDP or Others, where others indicates a specific protocol
number (0-255). (Options: TCP, UDP, Others; Default: TCP)
Source/Destination Port (0-65535). Source/destination port number for the specified protocol type. (Range: 0-
65535)
Control Code (0-63). Decimal number (representing a bit string) that specifies flag bits in byte 14 of the TCP
header. (Range: 0-63)
Control Code Bitmask (0-63). Decimal number representing the code bits to match. The control bitmask is a
decimal number (for an equivalent binary bit mask) that is applied to the control code. Enter a decimal number,
where the equivalent binary bit “1” means to match a bit and “0” means to ignore a bit. The following bits may be
specified:
• 1 (fin) – Finish
• 2 (syn) – Synchronize
• 4 (rst) – Reset
• 8 (psh) – Push
• 16 (ack) – Acknowledgement
• 32 (urg) – Urgent pointer
For example, use the code value and mask below to catch packets with the following flags set:
• - SYN flag valid, use control-code 2, control bitmask 2
• - Both SYN and ACK valid, use control-code 18, control bitmask 18
• - SYN valid and ACK invalid, use control-code 2, control bitmask 18