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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 47 Configuring Network Security with ACLs Configuring VLAN Maps
Denying Access to a Server on Another VLAN
Figure 47-4 shows how to restrict access to a server on another VLAN. In this example, server
10.1.1.100 in VLAN 10 has the following access restrictions:
Hosts in subnet 10.1.2.0/8 in VLAN 20 should not have access.
Hosts 10.1.1.4 and 10.1.1.8 in VLAN 10 should not have access.
Figure 47-4 Deny Access to a Server on Another VLAN
This procedure configures ACLs with VLAN maps to deny access to a server on another VLAN. The
VLAN map SERVER 1_ACL denies access to hosts in subnet 10.1.2.0/8, host 10.1.1.4, and host
10.1.1.8. Then it permits all other IP traffic. In Step 3, VLAN map SERVER1 is applied to VLAN 10.
To configure this scenario, follow these steps:
Step 1 Define the IP ACL to match and permit the correct packets.
Switch(config)# ip access-list extended SERVER1_ACL
Switch(config-ext-nacl))# permit ip 10.1.2.0 0.0.0.255 host 10.1.1.100
Switch(config-ext-nacl))# permit ip host 10.1.1.4 host 10.1.1.100
Switch(config-ext-nacl))# permit ip host 10.1.1.8 host 10.1.1.100
Switch(config-ext-nacl))# exit
Step 2 Define a VLAN map using the ACL to drop IP packets that match SERVER1_ACL and forward IP
packets that do not match the ACL.
Switch(config)# vlan access-map SERVER1_MAP
Switch(config-access-map)# match ip address SERVER1_ACL
Switch(config-access-map)# action drop
Switch(config)# vlan access-map SERVER1_MAP 20
Switch(config-access-map)# action forward
Switch(config-access-map)# exit
Step 3 Apply the VLAN map to VLAN 10.
Switch(config)# vlan filter SERVER1_MAP vlan-list 10.
Catalyst 4500 series switch Host (VLAN 20)
Host (VLAN 10)
Host (VLAN 10)
Server (VLAN 10)
94155
VLAN map
Subnet
10.1.2.0/8
10.1.1.100
10.1.1.4
10.1.1.8
Packet