1	Interconnecting Cisco Networking Devices Module 8 Access Lists
2	Overview Introduction to Access Lists Standard Access Lists Extended Access Lists Named Access Lists Monitoring Access Lists Summary
3	Introduction to Access Lists Essentially, a list of conditions that categorize packets. Standard Access Lists Extended Access Lists Named Access Lists Inbound Access Lists Outbound Access Lists
4	Standard Access Lists Filters traffic by examining the source IP Address in a packet Use access-list #’s 1-99 and 1300-1999 access-list ?
5	Wildcard Masking 172.16.30.5 0.0.0.0 <- specifies that host only 172.16.30.0 0.0.0.255 <- traffic has to match first 3 octets only 172.16.16.0 0.0.3.255 <- would match traffic from 172.16.16.0 to 172.16.19.0
6	Standard Access List Example Router (config)# access-list 10 deny 172.16.40.0 0.0.0.255 Router (config)# access-list 10 permit any ----- Router (config)# int e0 Router (config-if)# ip access-group 10 out -----
7	Controlling VTY (Telnet) Access Router (config)# access-list 50 permit 172.16.10.3 Router (config)# line vty 0 4 Router (config-line)# access-class 50 in
8	Extended Access Lists Can Filter traffic by examining the source IP Address, destination IP address, service, etc. in a packet Use access-list #’s 100-199 and 2000-2699 access-list ?
9	Extended Access List Example Router (config)# access-list 110 deny tcp any host 172.16.30.5 eq 21 Router (config)# access-list 110 deny tcp any host 172.16.30.5 eq 23 Router (config)# access-list 110 permit ip any any Router (config)# int s0 Router (config-if)# ip access-group 110 out
10	Named Access Lists Another way to create Standard and Extended Access Lists Allows you to remove individual lines, instead of re-creating the whole access list
11	Named Access List Example Router (config)# ip access-list standard BlockSales Router (config-std-nacl)# deny 172.16.40.0 0.0.0.255 Router (config-std-nacl)# permit any Router (config-std-nacl)# exit Router (config)# int s0 Router (config-if)# ip access-group BlockSales out
12	Useful Commands show access-list show access-list 110 show ip access-list show ip interface show running-config
13	Summary Place Standard Access Lists close to the destination Place Extended Access Lists close to the source Extremely useful
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