Private VLANs | 69933Private VLANsThe Private VLAN (PVLAN) feature is supported on platforms: c s zFor syntax details on the commands discussed in this chapter, see the Private VLANs Commands chapterin the FTOS Command Reference.This chapter contains the following major sections:• Private VLAN Concepts on page 700• Private VLAN Commands on page 701• Private VLAN Configuration Task List on page 702• Private VLAN Configuration Example on page 705• Inspecting the Private VLAN Configuration on page 706Private VLANs extend the FTOS security suite by providing Layer 2 isolation between ports within thesame VLAN. A private VLAN partitions a traditional VLAN into subdomains identified by a primary andsecondary VLAN pair. Private VLANs block all traffic to isolated ports except traffic from promiscuousports. Traffic received from an isolated port is forwarded only to promiscuous ports or trunk ports.Example uses of PVLANs:• A hotel can use an isolated VLAN in a private VLAN to provide Internet access for its guests, whilestopping direct access between the guest ports.• A service provider can provide Layer 2 security for customers and use the IP addresses moreefficiently, by using a separate community VLAN per customer, while at the same time using the sameIP subnet address space for all community and isolated VLANs mapped to the same primary VLAN.In more detail, community VLANs are especially useful in the service provider environment, because,multiple customers are likely to maintain servers that must be strictly separated in customer-specificgroups. A set of servers owned by a customer could comprise a community VLAN, so that those serv-ers could communicate with each other, and would be isolated from other customers. Another cus-tomer might have another set of servers in another community VLAN. Another customer might wantan isolated VLAN, which is has one or more ports that are also isolated from each other.
