No IP from DHCP server with ip-helper

[Clement BONNAL]

Hello,

I've a Cisco 1941W router which is DHCP server for data-VLANs and uses ip-helper for voice-VLANs.

Wired IP Phones (VLAN 100) gets IP successfully, but WiFi IP Phones (VLAN 101) doesn't.

Here is the trace of DHCP debug for VLAN101 which is NOK:

001898: *Jun 13 14:04:00.046: DHCPD: client's VPN is .

001899: *Jun 13 14:04:00.046: DHCPD: No option 125

001900: *Jun 13 14:04:00.046: DHCPD: Sending notification of DISCOVER:

001901: *Jun 13 14:04:00.046:   DHCPD: htype 1 chaddr 649e.f3b6.85da

001902: *Jun 13 14:04:00.046:   DHCPD: remote id 020a00000a432131fd000000

001903: *Jun 13 14:04:00.046:   DHCPD: circuit id 00000000

001904: *Jun 13 14:04:00.046: DHCPD: DHCPDISCOVER received from client 0164.9ef3.b685.da on interface BVI101.

001905: *Jun 13 14:04:00.046: DHCPD: Seeing if there is an internally specified pool class:

001906: *Jun 13 14:04:00.046:   DHCPD: htype 1 chaddr 649e.f3b6.85da

001907: *Jun 13 14:04:00.046:   DHCPD: remote id 020a00000a432131fd000000

001908: *Jun 13 14:04:00.046:   DHCPD: circuit id 00000000

001909: *Jun 13 14:04:00.046: DHCPD: there is no address pool for 10.67.33.49.

001910: *Jun 13 14:04:00.046: DHCPD: setting giaddr to 10.67.33.49.

001911: *Jun 13 14:04:00.046: DHCPD: BOOTREQUEST from 0164.9ef3.b685.da forwarded to 198.19.255.21.

001912: *Jun 13 14:04:00.046: DHCPD: BOOTREQUEST from 0164.9ef3.b685.da forwarded to 198.19.255.22.

And for VLAN 100 which is OK:

002781: *Jun 13 14:19:20.646: DHCPD: client's VPN is .

002782: *Jun 13 14:19:20.646: DHCPD: No option 125

002783: *Jun 13 14:19:20.646: DHCPD: DHCPREQUEST received from client 0150.57a8.876b.14.

002784: *Jun 13 14:19:20.646: DHCPD: no subnet configured for 10.65.33.58.

002785: *Jun 13 14:19:20.646: DHCPD: Finding a relay for client 0150.57a8.876b.14 on interface Vlan100.

002786: *Jun 13 14:19:20.646: DHCPD: Seeing if there is an internally specified pool class:

002787: *Jun 13 14:19:20.646:   DHCPD: htype 1 chaddr 5057.a887.6b14

002788: *Jun 13 14:19:20.646:   DHCPD: remote id 020a00000a41213101000064

002789: *Jun 13 14:19:20.646:   DHCPD: circuit id 00000000

002790: *Jun 13 14:19:20.646: DHCPD: there is no pool for 10.65.33.49.

002791: *Jun 13 14:19:20.646: DHCPD: setting giaddr to 10.65.33.49.

002792: *Jun 13 14:19:20.646: DHCPD: BOOTREQUEST from 0150.57a8.876b.14 forwarded to 198.19.255.21.

002793: *Jun 13 14:19:20.646: DHCPD: BOOTREQUEST from 0150.57a8.876b.14 forwarded to 198.19.255.22.

002794: *Jun 13 14:19:20.726: DHCPD: client's VPN is .

002795: *Jun 13 14:19:20.726: DHCPD: No option 125

002796: *Jun 13 14:19:20.726: DHCPD: forwarding BOOTREPLY to client 5057.a887.6b14.

002797: *Jun 13 14:19:20.726: DHCPD: Forwarding reply on numbered intf

002798: *Jun 13 14:19:20.726: DHCPD: no option 125

002799: *Jun 13 14:19:20.726: DHCPD: broadcasting BOOTREPLY to client 5057.a887.6b14.

Here is the router conf for both VLANs:

interface Vlan100

description ### VLAN Wired Voice ###

ip address 10.65.33.49 255.255.255.240

ip helper-address 198.19.255.21

ip helper-address 198.19.255.22

ip dns view-group splitdns

ip nat inside

ip virtual-reassembly in

ip tcp adjust-mss 1000

no autostate

crypto ipsec client ezvpn Vers-dCloud inside

!

interface Vlan101

description ### VLAN Wireless Voice ###

no ip address

bridge-group 101

!

interface BVI101

description ### BVI Wireless Voice ###

ip address 10.67.33.49 255.255.255.240

ip helper-address 198.19.255.21

ip helper-address 198.19.255.22

ip dns view-group splitdns

ip nat inside

ip virtual-reassembly in

ip tcp adjust-mss 1000

crypto ipsec client ezvpn Vers-dCloud inside

I don't know why I can't have IP from wireless voice VLAN whereas it is OK and wired voice VLAN and conf is the same!

Can you help me ?

Regards,

Clement

[Richard Burts]

Clement

The parts of the config that you have posted seem reasonable and I do not see a particular problem with them. The debug output is pretty clear that it is sending a request to the DHCP servers. It sort of implies that the servers are not sending a response. So my question to you is whether you can confirm that the DHCP servers have configured a scope for the subnet of 10.67.33.48?

HTH

Rick

[Clement BONNAL]

Hello Richard,

I agree with you, it seems to have no response from the DHCP servers for the 10.67.33.49/255.255.255.240 subnet.

As DHCP servers are not mine, I will contact support to check if scope is configured.

Regards,

Clement

[paul driver]

Hello

Just curious - Do you have IRB enabled

Bridge 101 protocol ieee

Bridger 101 route ip

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

[Clement BONNAL]

Hello Paul,

Yes you're true:

Router conf:

bridge 1 protocol ieee
bridge 1 route ip
bridge 101 protocol ieee
bridge 101 route ip
!
bridge irb

Integrated AP conf:

bridge 1 protocol ieee
bridge 1 route ip
bridge 101 protocol ieee

!
bridge irb

Clement