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6.4.1 Create a Standard Access List
Standard access lists filter at Layer 3, and can allow or block access to networks and host addresses. The
parameters for a standard access list are described below:
• Access list number (1–99): Identifies the access list to which an entry belongs. There is no limit to how many
entries make up an access list, other than available memory
• Remark: Access list entry comment. This may be useful to keep track of numbered lists
• Permit/deny: Indicates whether this entry allows or blocks traffic from the specified source address
• Source address: Enter the source IP address to match
• Any: Specifies any source address to match
• Source wildcard mask: Identifies which bits in the address field are to be matched. A “0” indicates that positions
must match; a “1” indicates that position is ignored
In the following example, a standard access list is created to allow all traffic from the 192.168.0.0 networks, while
blocking all non-192.168.0.0 traffic. The last entry is redundant, since the switch will deny access if there is no match
found by the end of the list.
Switch# configure
Switch(config)# access-list 1 ?
deny Specify packets to reject
permit Specify packets to forward
remark Access list entry comment
Switch(config)# access-list 1 permit ?
A.B.C.D Source address to match. e.g. 10.0.0.0
any Any source address to match
Switch(config)# access-list 1 permit 192.168.0.0 ?
A.B.C.D Source wildcard. e.g. 0.0.0.255
<cr>
Switch(config)# access-list 1 permit 192.168.0.0 0.0.255.255
Switch(config)# access-list 1 deny any
The next example shows a standard access list is created to deny all traffic from 192.168.123.254 and allow all other
traffic to be forwarded. Note that the last entry of this example is not redundant, as it is a permit statement. An implicit
deny statement would follow the last entry, if no match was found before the end of the list. In this case, however, you
are permitting any other IP address other than 192.168.123.254, and a deny statement is not necessary.
Switch(config)# access-list 1 deny 192.168.123.254 ?
A.B.C.D Source wildcard. e.g. 0.0.0.255
<cr>
Switch(config)# access-list 1 deny 192.168.123.254
Switch(config)# access-list 1 permit any
Switch(config)# exit
Switch# show access-list
After entering the access list, use the show command from privileged mode, as shown above. Any lists you have
created, as well as any remark entered for a list, will be displayed.
Note: In the above examples, the argument any can be used instead of 0.0.0.0 255.255.255.255.
60 Asante IntraCore IC36240 User’s Manual