setup Lock &Key ACL

username foobar password cisco

!

int s0

ip address 1.1.1.1 255.255.0.0

　　ip access-group 101 in

　　! /* or port 22 for ssh */

　　access-list 101 permit tcp any host 1.1.1.1 eq telnet

　　access-list 101 dynamic foobar permit ip any any

　　!

　　line vty 0 2

　　login local

　　autocommand access-enable host timeout 5

　　line vty 3 4

　　login local

　　rotary 1

　　The first access list allows telnet into the router. Your users will

　　telnet into router and authenticate with username foobar and password

　　"cisco"

　　The router will then immediately disconnect the telnet session. When

　　they successfully authenticate, an access list with their source IP will

　　be added to the dynamic list. Basically, if they authenticate correctly,

　　they can come in to the inside network. After 5 mins of inactivty the

　　entry will be deleted from the access list.

　　The vty 3 and 4 are using the rotary command so that you can telnet to

　　your router with the command: "telnet 1.1.1.1 3001" This takes you to

　　vty 3 (or 4). This way, you can telnet into the router and actually

　　manage it. A very subtle but VERY important point. If you forget this,

　　you'll be making a trip to use the console port.