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VLAN & Layer-2 Bridging

Objective

Validate that the zWAN Gateway Router can:

  • Create a tagged VLAN on a LAN interface and serve DHCP on that VLAN.
  • Bridge a VLAN interface with another LAN interface (same L2 domain).
  • Route between VLANs only when LAN↔LAN forwarding is enabled.

Prerequisites

  • Admin access to zWAN Director UI.
  • One z40 (branch) online in Director.
  • Two test clients:
    • Client A (Windows or Linux) connected to a VLAN-aware switch trunk or an endpoint NIC that can tag VLANs.
    • Client B connected to an untagged access port for LAN01 (for the bridge test).
  • Known LAN addressing for your default LAN (typically LAN00 untagged).
  • (Optional) An external switch port configured:
    • Trunk carrying VLAN 20 (tagged) to z40 LAN00.
    • Access port for LAN01 (untagged).

Test 1 — Create VLAN on LAN00 and enable DHCP

A. Add VLAN (tagged) on LAN00

  1. Director: Edge Controllers > [Device] > Network > Interfaces.
  2. On the LAN00 card, click the  menu → Add VLAN.
  3. In Add VLAN:
    • Tag: 20 (use any 1–4094 that fits your design).
    • Description: LAN00 VLAN 20.
    • Click Add.
      (You should now see LAN00 VLAN 20 listed under VLANs on that card.)

B. Add DHCP scope for the new VLAN

  1. Go to Network > DHCP > Manage.
  2. Click New Subnet.
  3. In Available, choose the VLAN you just created (e.g., 10.10.64.0/255.255.255.0 (LAN00 vlan 20)).
  4. Fill out the subnet details (example):
    • Network: 10.10.64.0
    • Netmask: 255.255.255.0
    • Default Gateway: 10.10.64.1 (z40 will own this on the VLAN interface)
    • DNS: as appropriate (e.g., 10.10.64.1 or your upstream resolver)
    • IP Range: 10.10.64.100 – 10.10.64.110 (or your preferred pool)
    • Lease timers as desired.
  5. Click Create then Save Changes (if shown).

C. Validate DHCP & Internet reachability

  • Wire the client:
    • Connect Client A to a switch trunk that tags VLAN 20 towards the z40 (or configure the client NIC to tag VLAN 20).
  • On Windows (Client A):
    • ipconfig /release then ipconfig /renew
    • Confirm you receive an IP in 10.10.64.0/24, gateway 10.10.64.1, DNS as configured.
    • ping 10.10.64.1 (default gateway) → success
    • ping 8.8.8.8 (or another reachable IP) → success
    • nslookup amzetta.com (or any domain) → success
  • On Linux (Client A):
    • ip addr (verify VLAN sub-interface or VLAN-aware port got address)
    • ping -c 3 10.10.64.1 and ping -c 3 8.8.8.8
    • dig amzetta.com (or nslookup) to verify DNS

Pass criteria

  • Client A receives a DHCP lease from the VLAN pool and can reach the gateway and the Internet.

Test 2 — Bridge a VLAN to another LAN (same L2 domain)

A. Create a bridge

  1. Director: Edge Controllers > [Device] > Network > Bridges → Create Bridge.
  2. Description: test.
  3. Interfaces: select LAN00 VLAN 20 and LAN01.
  4. (Optional) Tune STP/bridge timers if needed; leave defaults for POC.
  5. Click Create. The bridge card will show its IP (e.g., 10.10.64.1) and members.

B. Validate L2 connectivity across ports

  • Connect Client B to LAN01 (untagged).
  • Give Client B a DHCP lease by enabling DHCP on the bridged subnet if not already active:
    • If you created the DHCP scope in Test 1 on the VLAN interface, it will also serve clients on the bridge (same broadcast domain).
  • Verify on Client B:
    • Gets an IP in 10.10.64.0/24, gateway 10.10.64.1.
    • ping Client A’s IP (should succeed—same VLAN/L2 domain).
    • arp -a (Win) / arp -n (Linux) shows the peer’s MAC.

Pass criteria

  • Clients on LAN00 VLAN 20 and LAN01 are in the same L2 domain (can ARP each other and communicate without routing).

Test 3 — Inter-VLAN routing behavior & forwarding controls

Note: Default LAN is LAN00 (untagged). Inter-VLAN routing only occurs when LAN↔LAN forwarding is enabled.

A. Prepare a second VLAN (optional quick check)

  • Repeat Test 1 with VLAN 30 on LAN00 and give it a distinct DHCP scope (e.g., 10.10.30.0/24).

B. Check forwarding toggles

  1. Director: Network > Router > Routes.
  2. At the top, review Forwarding toggles:
    • LAN ↔ LAN must be ON for inter-VLAN routing.
    • WAN ↔ LAN governs WAN reachability; keep ON for Internet testing.

C. Validate routing on/off

  • With LAN ↔ LAN OFF:
    • Place Client A on VLAN 20 and Client B on VLAN 30.
    • ping between clients should fail (no inter-VLAN routing).
  • Turn LAN ↔ LAN ON:
    • ping between clients on VLAN 20 and VLAN 30 should now succeed (L3 routing through the z40).

Pass criteria

  • Inter-VLAN traffic follows the LAN↔LAN forwarding toggle as expected.

Troubleshooting / Tips

  • No DHCP on VLAN clients
    • Ensure the DHCP scope was created for the VLAN (selected from the “Available” dropdown when adding the subnet).
    • Confirm the switch port to the z40 is a trunk carrying the VLAN tag; client port must be access (untagged) for bridged interface or tagged if NIC is tagging.
  • Clients can’t talk across VLANs
    • Check LAN ↔ LAN toggle under Router > Routes.
    • Verify clients are actually in different subnets and have the z40 as default gateway.
  • Bridge not passing traffic
    • Confirm the bridge members are the intended interfaces (e.g., LAN00 VLAN 20 and LAN01).
    • If you use STP on upstream switches, avoid topology loops; enable the bridge’s STP toggle if needed.
  • Quick client commands
    • Windows: ipconfig /all, arp -a, ping <ip>, tracert <ip>
    • Linux: ip addr, nmcli dev show, arp -n, ping -c 3 <ip>, traceroute <ip>

Clean-Up

  • DHCP: remove the VLAN scopes you created.
  • BridgesNetwork > Bridges → ⋮ → Remove Bridge.
  • VLANsNetwork > Interfaces → on the parent interface ⋮ → (Manage/Remove VLAN) as applicable.

Validation Summary

  • VLAN creation and DHCP on tagged VLAN confirmed.
  • Bridge successfully places VLAN and LAN interfaces into the same L2 segment.
  • Inter-VLAN routing adheres to LAN↔LAN forwarding control.
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