Standard IP Access Lists
Standard IP access lists filter network traffic by examining the source IP address in a packet.
You create a standard IP access list by using the access-list numbers 1–99 or 1300–1999
(expanded range). Access-list types are generally differentiated using a number. Based on the
number used when the access list is created, the router knows which type of syntax to expect as
the list is entered.
By using numbers 1–99 or 1300–1999, you’re telling the router that you want to create a
standard IP access list, so the router will expect syntax specifying only the source IP address in
the test lines.
The following is an example of the many access-list number ranges that you can use to filter
traffic on your network (the protocols for which you can specify access lists depend on your IOS
version):