Dude, look at your DHCP

raymondtun · ‎02-13-2013

Hi,

I am configuring DHCP pool for voice vlan on cisco 2921 router.

Here is the setup.

2921 router -> 3750 -> 2960 PoE -> 7942 IP Phone

Router Config

ip dhcp excluded-address 10.146.54.1 10.146.89.50

!

ip dhcp pool VoiceVlan

network 10.146.54.0 255.255.255.0

subnet prefix-length 24

dns-server 10.144.68.32 10.144.68.33

option 150 ip 10.146.68.36

default-router 10.146.54.1

netbios-name-server 10.144.68.32 10.144.68.33

netbios-node-type h-node

domain-name wft.root.loc

lease 0 8

interface GigabitEthernet0/0

ip address 10.144.54.16 255.255.255.0

duplex full

speed 1000

!

interface GigabitEthernet0/0.50

encapsulation dot1Q 50

ip address 10.146.54.15 255.255.255.0

!

3750 Config

interface GigabitEthernet1/0/3

description To Router

switchport access vlan 54

switchport mode access

switchport voice vlan 50

speed 1000

duplex full

spanning-tree portfast

interface Vlan50

description VoiceVLAN

ip address 10.146.54.1 255.255.255.0

interface Vlan54

ip address 10.144.54.1 255.255.255.0

2960 Config

interface FastEthernet0/1

switchport access vlan 50

switchport mode access

spanning-tree portfast

!

Troubleshooting

Trunk is formed

2960#sh int tru

Port Mode Encapsulation Status Native vlan

Gi0/3 on 802.1q trunking 1

Port Vlans allowed on trunk

Gi0/3 1-4094

Port Vlans allowed and active in management domain

Gi0/3 1,50,54

Port Vlans in spanning tree forwarding state and not pruned

Gi0/3 1,50,54

Router received the dhcp discover from IP Phone, but it doesn't issue any IP. Here is the debug log

875525: Feb 13 15:11:26.167 GMT+8: IP: s=0.0.0.0 (GigabitEthernet0/0.50), d=255.255.255.255, len 576, input feature

875526: Feb 13 15:11:26.167 GMT+8: UDP src=68, dst=67, MCI Check(80), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

875527: Feb 13 15:11:26.167 GMT+8: FIBipv4-packet-proc: route packet from GigabitEthernet0/0.50 src 0.0.0.0 dst 255.255.255.255

875528: Feb 13 15:11:26.167 GMT+8: FIBfwd-proc: Default:255.255.255.255/32 receive entry

875529: Feb 13 15:11:26.167 GMT+8: FIBipv4-packet-proc: packet routing failed

875530: Feb 13 15:11:26.167 GMT+8: IP: s=0.0.0.0 (GigabitEthernet0/0.50), d=255.255.255.255, len 576, rcvd 2

875531: Feb 13 15:11:26.167 GMT+8: UDP src=68, dst=67

875532: Feb 13 15:11:26.167 GMT+8: IP: s=0.0.0.0 (GigabitEthernet0/0.50), d=255.255.255.255, len 576, stop process pak for forus packet

875533: Feb 13 15:11:26.167 GMT+8: UDP src=68, dst=67

875534: Feb 13 15:11:26.167 GMT+8: DHCPD: client's VPN is .

875535: Feb 13 15:11:26.167 GMT+8: DHCPD: No option 125

875536: Feb 13 15:11:26.167 GMT+8: DHCPD: DHCPDISCOVER received from client 0110.bd18.0149.5b on interface GigabitEthernet0/0.50.

Any help is appreciated.

Cheers!

Terry Cheema · ‎02-13-2013

Will try to have a look once have some time but if you move this post to Network infrastructure > LAN switching and routing section you will get more feedback.

Terry

Sent from Cisco Technical Support iPad App

techslusk · ‎04-03-2015

Dude, look at your DHCP exclude on your router.

It is supposed to be low/high IP.

So basicly you told the router to exclude IP address from 10.146.54.1 to 10.146.89.5.

This means that DHCP will not hand out 10.146.54.1 through 10.146.89.5

try

ip dhcp excluded-address 10.146.54.1 10.146.54.15

Hope this helps.

Also, I know this is years ago but thought I would throw that out there.

DHCP for Voice VLAN