It's important to remember that all access lists have implicit deny at the last line. This is not what we wanted to achieve. To correct this problem, and deny only packets with source address 222.122.122.100, we need to add another line to our access list. When creating access list with a deny directive, it's important to add another line that allows all or some traffic, or you will just shut down the router. When creating an access list that includes an entire network or subnet, you should use wildcard masking.
Wildcard mask is somewhat similar to the subnet mask.
In this example we created access list that permits traffic from all hosts on a network 222.122.122.0. The wildcard mask of 0.0.0.255 tells the router that the first 3 octets must match up exactly, and the last octet is any number from 0 to 255. You can have many access lists on a router, but they don't do anything until you apply an access list to an interface. To apply an access list to an interface, you must first enter an interface configuration mode. For multiport router you have to decide whether to apply an access list to an inbound or outbound traffic based on the needs of the network.