Hands-On Lab: Configuring VTP Transparent Mode

Lab Objective

Configure a switch in VTP transparent mode between an existing VTP server and client, verify it does not apply server-originated VLAN changes to its own database, but still forwards those advertisements onward, and confirm it can independently create its own local VLANs.

Lab Purpose

Transparent mode is often misunderstood: a transparent switch behaves like neither a server nor a client for its own VLAN database, yet it still relays VTP advertisements between other switches physically connected through it. Understanding this dual behavior is essential to correctly diagnosing why a VLAN appears on some switches but not others in a VTP domain.

Lab Topology

SwitchServer ---- SwitchTransparent ---- SwitchClient

All three switches connected via trunk links,
all in VTP domain CorpNet (SwitchServer and
SwitchClient already configured from the
previous lab)

Task 1: Configure Transparent Mode

On the middle switch, join the same VTP domain and explicitly set VTP mode to transparent.

Task 2: Create a VLAN on the Server

On SwitchServer, create VLAN 40 named Sales.

Task 3: Verify the Transparent Switch Does Not Apply the VLAN Locally

Check SwitchTransparent's own VLAN database and confirm VLAN 40 is NOT automatically added there.

Task 4: Verify the VLAN Still Reaches the Client

Check SwitchClient's VLAN database and confirm VLAN 40 DID successfully propagate through the transparent switch to reach it.

Task 5: Create a Local VLAN on the Transparent Switch

Create VLAN 50 named LocalOnly directly on SwitchTransparent, and confirm it does NOT appear on either SwitchServer or SwitchClient.

Solution and Verification

SwitchTransparent(config)# vtp domain CorpNet
SwitchTransparent(config)# vtp mode transparent

Setting device to VTP TRANSPARENT mode

SwitchServer(config)# vlan 40
SwitchServer(config-vlan)# name Sales
SwitchServer(config-vlan)# exit

SwitchTransparent# show vlan brief

VLAN Name       Status    Ports
---- ---------- --------- -----
1    default    active
-- VLAN 40 is absent here -- a transparent
-- switch never applies received VTP changes
-- to its own local database

SwitchClient# show vlan brief

VLAN Name       Status    Ports
---- ---------- --------- -----
30   Engineering active
40   Sales       active
-- Yet VLAN 40 successfully reached the client,
-- confirming SwitchTransparent forwarded the
-- advertisement onward without applying it locally

SwitchTransparent(config)# vlan 50
SwitchTransparent(config-vlan)# name LocalOnly
SwitchTransparent(config-vlan)# exit

SwitchServer# show vlan brief | include 50
-- (no output -- VLAN 50 never appears)

SwitchClient# show vlan brief | include 50
-- (no output -- VLAN 50 never appears)

Key Takeaway

A transparent-mode switch is functionally split in two: it acts purely as a pass-through relay for VTP advertisements originating elsewhere in the domain, while simultaneously maintaining a completely independent, locally managed VLAN database that neither sends updates to nor receives updates from any other switch — VLANs created on it stay strictly local, and VLANs created elsewhere pass through it but never take effect on it.