Question : Problem: dhcp vlan issue

3825 c--T1link---3825 d ----3750--DHCP-srvr
 


i am not able to get an ip address on his ip phone connected to a NME16 MODULE
on his 3825c router. when the port is configured as an access port (either vlan
1 or vlan 60) the pc and the phone get their ip addresses. when i try using  a trunk
with the voice vlan and the native vlan as  the data vlan it works half the times and does
not the other half.
i am encountering the same issue with hwic4esw module on the same router and tried different
code versions.

as seen below,i tired allowing only voice and data vlan but had to add the default vlans (required in some versions)

switchport mode trunk
switchport trunk encap dot1q
switchport trunk native vlan
switchport voice vlan
switchport trunk allowed vlan  -

I attempted to change native vlan to 2 instead of 1 but that did not help.


Also ran a debug for udp packets and saw that the dhcp discover and broadcast messages are reaching the
dhcp server and the server is responding back with and is reaching both vlans voice and data on the 3825c



i know ethersw module doesnt support voice-vlan packets when the mode is access for the port and that is why
the access and voice vlan configuration is not working.

can i have this working with the trunk configuration

Answer : Problem: dhcp vlan issue

How is your DHCP server configured in terms of addresses it is handing out to the phone and the PC? do you have a different scope for phones? If so how are you distinguishing which vlan is which when it gets a DHCP request from the phone? IE, the phone sends a DHCP broadcast on Vlan-voice and the phone PC sends one on Vlan-data, are they still separate when they hit the DHCP server? Or is there only one DHCP helper address?