1. Each package will be compared to each row in the Access List rule sequentially
2. If found suitable conditions stretcher packet will follow the existing rules in the Access List.
3. If the package does not find a corresponding rule then the packet is not allowed to pass or access the network.
Application of the access list itself is divided into two kinds, among others:
1. Standard Access List - do the screening packet by packet sender IP address.
2. Extended Access List - select a package based on the sender and receiver IP tools, protocols, and port types of packets sent.
When the ACL is configured on a router, the ACL must have a unique identification number given to him. This number indicates the type of access list is created and must be at a certain range of numbers valid for this type of list.
Type of ACL | Range Number |
---|---|
IP Standard | 1-99 |
IP Extended | 100-199 |
IPX Standard | 800-899 |
IPX Extended | 900-999 |
Apple Talk | 600-699 |
IPX SAP Filter | 1000-1099 |
Standard configuration Acess List
Based on the table above, the standard access list will make the
selection of packages using the sender's IP address range identifier
number that can be used is the number 1 to 99.
Here is the formula:
Router(config)# access-list [identifier number] {permit/deny} [sender address] [wildcard-mask]
Case Access List:
There are 2 Routers, switch, server, 2 PC and Laptop. The rules is,
Laptop with ip 10.10.10.2 can access web of server on ip 20.20.20.2. But
other PC with ip 10.10.10.3 and 10.10.10.4 can't access to the website
of server. Here is the configuration:
1. Set IP
- PC1: 10.10.10.2
- PC2: 10.10.10.3
- PC3: 10.10.10.4
- Server: 20.20.20.2
2. Router 5
- Se1/0 : 12.12.12.1 255.255.255.0
- Fa0/0 : 10.10.10.1 255.255.255.0
3. Router 6
- Se1/0 : 12.12.12.2 255.255.255.0
- Fa0/0 : 20.20.20.1 255.255.255.0
- IP Route : ip route 20.20.20.0 255.255.255.0 12.12.12.2
- Access List:
Fa0/0 : ip access-group 100 out
access-list 100 permit tcp host 10.10.10.2 host 20.20.20.2 eq www
access-list 100 deny tcp any host 20.20.20.2 eq www
access-list 100 permit ip any