Private VLAN

  • Members of an isolated VLAN can only communicate with the promiscuous ports mapped
  • Members of a community VLAN can communicate with members of the same community and the promiscuous ports.

A two-way community acts like a regular community but has the additional aspect of allowing access control lists to check traffic going to and from (two ways) the VLAN and provides enhanced security within a private VLAN.

To configure PVLAN, VTP should be in transparent mode.

  1. Create primary private-vlan
  2. Create isolated/community VLAN
  3. Associating isolated/community VLANs to primary
  4. Configure spanning-tree mode and associating ports to PVLANs
  5. Mapping PVLANs under the primary VLAN interface
  6. To verify: show interface [primary PVLAN] private-vlan mapping

IPExpert, Vol.1, 2.28

You must configure VTP to transparent mode before you can create a private VLAN.
Private VLANs are configured in the context of a single switch and cannot have members on other switches. Private VLANs also carry TLVs that are not known to all types of Cisco switches.


SWITCH(config)# vlan primary_number
SWITCH(vlan-config)# private-vlan primary
SWITCH(config)# vlan secondary_number
SWITCH(vlan-config)# private-vlan [isolated | community]
SWITCH(config)# vlan primary_number
SWITCH(vlan-config)# private-vlan association secondary_number_list [add secondary_number_list]
SWITCH(config)# interface type mod/port
SWITCH(config-if)# switchport
SWITCH(config-if)# switchport mode private-vlan host
SWITCH(config-if)# switchport mode private-vlan host-association primary_number secondary_number
SWITCH(config)# interface type mod/port
SWITCH(config-if)# switchport
SWITCH(config-if)# switchport mode private-vlan promiscuous
SWITCH(config-if)# switchport mode private-vlan mapping primary_number secondary_number
SWITCH(config)# interface primary_number
SWITCH(config-if)# ip address address mask
SWITCH(config-if)# private-vlan mapping primary_number secondary_number
show vlan private-vlan type
show interface private-vlan mapping
show interface type mod/port switchport
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Author: Mo Moghaddas

Yet another full-time traveler, casually [angel] investing in hopes and ideas solving problems or making life easier, landscape photographing as a hobby, and enthusiastic about Blockchain/Cryptocurrency. Internet citizen, building and breaking Network Architectures by day, and passionate about what may happen #in_future :-)

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