Cisco WS-C3750-48PS-S User Manual

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Catalyst 3750 Switch Software Configuration Guide
78-16180-02
Chapter 31 Configuring Network Security with ACLs
Configuring VLAN Maps
Denying Access to a Server on Another VLAN
You can restrict access to a server on another VLAN. For example, server 10.1.1.100 in VLAN 10 needs
to have access denied to these hosts (see Figure 31-5):
• 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 31-5 Deny Access to a Server on Another VLAN
This example shows how to deny access to a server on another VLAN by creating the VLAN map
SERVER 1 that denies access to hosts in subnet 10.1.2.0.8, host 10.1.1.4, and host 10.1.1.8 and permits
other IP traffic. The final step is to apply the map SERVER1 to VLAN 10.
Step 1 Define the IP ACL that will match 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 this ACL that will 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.
Layer 3 switch
Host (VLAN 20)
Host (VLAN 10)
Host (VLAN 10)
Server (VLAN 10)
101356
VLAN map
Subnet
10.1.2.0/8
10.1.1.100
10.1.1.4
10.1.1.8
Packet

Cisco WS-C3750-48PS-S Specifications

General

Brand	Cisco
Model	WS-C3750-48PS-S
Category	Switch
Language	English