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
•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
Switch# configure | 1 | ? | |
Switch(config)# | |||
deny | Specify packets to reject | ||
permit | Specify packets to forward | ||
remark | Access list entry comment | ||
Switch(config)# | 1 | permit ? | |
A.B.C.D | Source address to match. e.g. 10.0.0.0 | ||
any | Any source address | to match | |
Switch(config)# | 1 | permit 192.168.0.0 ? | |
A.B.C.D | Source wildcard. e.g. 0.0.0.255 | ||
<cr> |
|
| permit 192.168.0.0 0.0.255.255 |
Switch(config)# | |||
Switch(config)# | 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)#
<cr>
Switch(config)#
Switch(config)#
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 |