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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 v alid, use control-code 18, control bitmask
18
- SYN valid and ACK invalid, use control-code 2, control bitmask
18
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 select “IP,” enter a subnet
address and the mask for an address range. Set any other required criteria,
such as service type, protocol type, or TCP contro l code. Then click Add.
Figure 3-37 ACL Configuration - Extended IP
CLI – This example adds two rules:
1. Accept any incoming packets if the source address is in subnet 10.7.1.x.
For example, if the rule is matched; i.e., the rule (10.7.1.0 &
255.255.255.0) equals the masked address (10.7.1.2 & 255.255.255.0),
the packet passes through.
2. Allow TCP packets from class C addresses 192.168.1.0 to any
destination address when set for destination TCP port 80 (i .e., HTTP).