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  • 1.  DHCP Relay not working across switches

    Posted 02-01-2024 11:26 AM


    I have 2 x 1930 48 port, connected via an RJ45 cable. I have 3 VLANs ( 1,10,20 ) with 1 being wired devices, 10 being for wifi ( via AP22s ) and 20 being for Voice. All ports are default VLAN 1, tagged 10 and 20

    DHCP Relay is configured, and on the switch with routing configured this works fine - devices across all VLANS get IP addresses. On the switch operating at L2, devices in the Voice VLAN do not get IP addresses. LLDP-MED shows them being picked up as phones and being active on VLAN 20 - but no IP addresses. Devices in VLAN 10 ( wifi ) get IP addresses fine.

    Has anyone seen this before? I'm at a bit of a loss as to why just the voice VLAN doesn't get an IP address on the L2 switch


    Darren Durbin

  • 2.  RE: DHCP Relay not working across switches

    Posted 02-05-2024 12:03 PM

    Hi Darren I am getting exactly the same issue.

    I have also set PVID the same as the Voice VLAN in my case VLAN30.

    Tagged VLAN 30 Untagged VLAN 10 data.

    I have also added the ports into Voice Vlan interface settings.

    I added the for 3 bytes Mac in my case 9C:75:14 into the Telephony OUI  for teh Mac addresses

    Alan Richardson

  • 3.  RE: DHCP Relay not working across switches

    Posted 02-05-2024 03:48 PM

    Hi Alan - I've managed to resolve this by going to VLAN->Voice VLAN Configuration on the 'second' switch ( the non-routing one, acting just as Layer2 switch ) and setting Admin Voice VLAN Membership to Disabled on all ports.

    Why this works I have no idea.

    Darren Durbin