Question:
Acme is a small shipping company that has an existing enterprise network comprised of 2 switches;DSW1 and ASW1. The topology diagram indicates their layer 2 mapping. VLAN 40 is a new VLAN that will be used to provide the shipping personnel access to the server. For security reasons, it is necessary to restrict access to VLAN 20 in the following manner:
- Users connecting to ASW1’s port must be authenticate before they are given access to the network. Authentication is to be done via a Radius server:
- Radius server host: 172.120.39.46
- Radius key: rad123
- Authentication should be implemented as close to the host device possible.
- Devices on VLAN 20 are restricted to in the address range of 172.120.40.0/24.
- Packets from devices in the address range of 172.120.40.0/24 should be passed on VLAN 20.
- Packets from devices in any other address range should be dropped on VLAN 20.
- Filtering should be implemented as close to the server farm as possible.
The Radius server and application servers will be installed at a future date. You have been tasked with implementing the above access control as a pre-condition to installing the servers. You must use the available IOS switch features.
1) Configure ASW1
Enable AAA on the switch:
ASW1(config)#aaa new-model
The new-model keyword refers to the use of method lists, by which authentication methods and sources can be grouped or organized.
Define the server along with its secret shared password:
ASW1(config)#radius-server host 172.120.39.46 key rad123
ASW1(config)#aaa authentication dot1x default group radius
This command causes the RADIUS server defined on the switch to be used for 802.1x authentication.
Enable 802.1x on the switch:
ASW1(config)#dot1x system-auth-control
Configure Fa0/1 to use 802.1x:
ASW1(config)#interface fastEthernet 0/1
ASW1(config-if)#switchport mode access
ASW1(config-if)#dot1x port-control auto
Notice that the word "auto" will force connected PC to authenticate through the 802.1x exchange.
ASW1(config-if)#exit
ASW1#copy running-config startup-config
2) Configure DSW1:
Define an access-list:
DSW1(config)#ip access-list standard 10 (syntax: ip access-list {standard | extended} acl-name)
DSW1(config-ext-nacl)#permit 172.120.40.0 0.0.0.255
DSW1(config-ext-nacl)#exit
Define an access-map which uses the access-list above:
DSW1(config)#vlan access-map MYACCMAP 10 (syntax: vlan access-map map_name [0-65535] )
DSW1(config-access-map)#match ip address 10 (syntax: match ip address {acl_number | acl_name})
DSW1(config-access-map)#action forward
DSW1(config-access-map)#exit
DSW1(config)#vlan access-map MYACCMAP 20
DSW1(config-access-map)#action drop (drop other networks)
DSW1(config-access-map)#exit
Apply a vlan-map into a vlan:
DSW1(config)#vlan filter MYACCMAP vlan-list 20 (syntax: vlan filter mapname vlan-list list)
DSW1#copy running-config startup-config
