Riverstone Networks RS Switch Router User Guide Release 8.0 25-13
Security Configuration
Layer-4 Bridging and Filtering
To illustrate this, the following diagram shows an RS serving as a bridge for a consultant host, file server, and an
engineering host, all of which reside on a single subnet.
Figure 25-2 Sample VLAN for layer-4 bridging
You may want to allow the consultant access to the file server for e-mail (SMTP) traffic, but not for Web (HTTP) traffic
and allow e-mail, Web, and FTP traffic between the engineer and the file server. You can use Layer-4 bridging to set
this up.
Setting up Layer-4 bridging consists of the following steps:
•
Creating an IP or IPX VLAN
•
Placing the ports on the same VLAN
•
Enabling Layer-4 Bridging on the VLAN
•
Creating an ACL that specifies the selection criteria
•
Applying an ACL to a port
25.4.1
Creating an IP or IPX VLAN for Layer-4 Bridging
To enable Layer-4 bridging on a VLAN, the VLAN must be configured to pass only IP or only IPX traffic. (Therefore,
you cannot enable Layer-4 bridging on port-based VLANS.) To create an IP or IPX VLAN, enter the following
command in Configure mode:
For example, to create an IP VLAN called “blue” with an ID of 21, enter the following command in Configure mode:
Create an IP or IPX VLAN.
vlan create
<vlan-name> <type>
id
<num>
rs(config)#
vlan create blue ip id 21
et.1.1
et.1.2
Consultant
File Server
Router
1.1.1.1/24
1.1.1.2/24
Engineer
et.1.3
1.1.1.3/24
