Learning by Doing: CISCO Certified Network ... - SCN Research

Table 1—ACL numbering.
1-99 IP standard
100-199 IP extended
200-299 Protocol type-code
300-399 DECnet
400-499 XNS standard
500-599 XNS extended
600-601 Appletalk
700-799 48-bit MAC address
800-899 IPX standard
900-999 IPX extended
1000-1099 IPX SAP
1100-1199 Extended 48-bit MAC address
1200-1299 IPX summary address
Standard ACL’s
A standard ACL controls access using an IP address or range of addresses. The best way
to figure these out is to dig right in and learn by doing! Let’s write a standard ACL to for
hosts on the sales network to be denied access to the HR server, but allow them access to
the marketing network and the WWW.
server
HR
192.168.10.15/24 192.168.10.0/24
e0/0
e0/1 WWW
s0/0
EGR e0/2
192.168.30.0/24
Sales
192.168.40.0/24
Now lets create our ACL:
Router(config)#access-list 1 deny 192.168.40.0 0.0.0.255
Router(config)#access-list 1 permit ip any
Here we created our access-list and gave it the number 1 (tells us it is a standard
ACL…see table 1). Then we put in our source IP’s (in this case a network) and the
wildcard mask. In this mask we wanted to exactly match the network and subnet portion
and didn’t really care about the host portions. Therefore our mask became 0.0.0.255
(nnnnnnnn.nnnnnnnn.ssssssss.hhhhhhhh).
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