Hi Sadik,
One solution could be to use policy-based routing similarly to this:
ip access-list extended Non_company_users
permit ip x.x.x.x x.x.x.x y.y.y.y y.y.y.y
route-map Non_company_users permit 10
match ip address Non_company_users
set default interface serial1/1
interface fa0/0
ip policy route-map Non_company_users
This solution will route the traffic defined by the access-list to the interface that leads to the service provider and will override the default route in the routing table.
Notes:
- The "ip policy route-map" command should be configured on the interface(s) receiving traffic from the non-company users, in the example fa0/0 LAN interface.
- Use the "set default interface" only if there is no explicit route in the routing table to the destination ip addresses for the traffic.
If the router finds explicit routes in the routing table, it will ignore the default interface.
- In general situations you can use the "set ip next-hop" command in the route-map.
Cheers:
Istvan