two interfaces sharing same wan?

[ilpadrino]

my 2811 has 2 interfaces plus a wic ethernet for internet. it also has a 4 port switch. is it possible to setup separate lan's that share the internet, but cannot communicate?

 

[chipk]

Should be possible, but it looks like it depends on your switch module:

http://www.cisco.com/en/US/products/ps5854/products_qanda_item0900aecd802a9470.shtml

 

[ilpadrino]

thanks, i think i've worked it out today. i had to use a combination of vlans and access lists. not sure if this is the best method, but it seems to work so far. the switch module is the 4ESW by the way, and IOS is 12.4. my router only has one routing interface. so i had to make 2 vlans and i'm using the 4ESW to connect to those vlans. both subnets are able to get to internet, but not talk to each other. actually the router interface is also a different ip and subnet, and the wan port is publicly assigned by the isp. i also setup a vpn, which i did not mention earlier. the one vlan can access our corporate network over that crypto map, while the second vlan cannot, and will be used for internet-only access.

next i'll see if 2 dhcp pools will intelligently know which address to assign depending on vlan.