Asus GigaX2024SX - Manual (Page 84)

Default: TCP)
• Source/Destination Port – Source/destination port number for the specified
protocol type. (Range: 0-65535)
• Control Code – Decimal number (representing a bit string) that specifies flag
bits in byte 14 of the TCP header. (Range: 0-63)
• Control Code Bitmask – 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
ntrol-code 2, control bitmask 18
s and the
s range. Set any othe required criteria, such as service type,
- SYN valid and ACK invalid, use co
Web – Specify the action (i.e., Permit or Deny). Specify the source and/or
destination addresses. Select the address type (Any, Host, or IP). If you select
“Host,” enter a specific address. If you sel ct “IP,” enter a subnet addres
e
r mask for an addres
protocol type, or TCP control code. Then click Add.
Figure 3-37. Configuring Extended ACLs
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