Hi there, I want to know more about configuring routers i.e how to set an access control list to enable/disable some ip's on the network .Are the settings volatile or they can be saved permanently .Kindly let me know the commands. Also are there any sites which give examples of such acls ? Thanks

check out www.cisco.com. do a search on ACL's.

Howdy. The ACLs are stored in the config, so if you save the config after you define them, they'll be present when and if the router reloads. To specify an ACL, you have to be in global config mode. Type: access-list # permit|deny IPaddr wildcardmask All ACLs have an implicit deny any statement at the end, so to block all hosts except a few, you'll create an ACL to permit those hosts; but to allow all hosts except a few, you'd define the ACL and put a permit any at the end. All ACL statements must have they're own line. So to define an ACL to block only 192.168.0.48 you'd do this: router# access-list 1 deny host 192.168.0.48 [enter] router# access-list 1 permit any[enter] Also note, you can only use ACL numbers 1-99. These are standard ACLs that are used to permit or deny hosts, either specifically, or an entire subnet. ACL numbers 100-199 are extended ACLs that can be used to permit or deny specific protocols (ICMP, TCP, FTP, HTTP) or ports. Once you've created your ACL, you need to assign it to an interface. To assign it to an interface, goto interface config mode for the interface that it's to be specified to: router(config)# int e0 (or fa0/0 if 2600ser) Then you need to issue the ip access-group comand to bind the ACL to an interface. ip access-group # in|out The in|out specifies whether or not the ACL is to permit/deny coming in the router, or going out. Hope this helps some. - Tosk