can't get address from DHCP...

snickered

I have a UC520 and have plugged a 7960 into fa0/1/0 but it won't get an address from DHCP. Here's what I have:

UC520#sh run int fa0/1/0
Building configuration...

Current configuration : 110 bytes
!
interface FastEthernet0/1/0
switchport access vlan 2
switchport voice vlan 3
spanning-tree portfast
end

UC520#sh run | se dhcp
ip dhcp excluded-address 10.10.3.0 10.10.3.20
ip dhcp pool VOICE
network 10.10.3.0 255.255.255.128
default-router 10.10.3.1
dns-server 10.10.3.1
option 150 ip 10.10.3.2

UC520#sh run int fa0/0.3
Building configuration...

Current configuration : 105 bytes
!
interface FastEthernet0/0.3
encapsulation dot1Q 3 native
ip address 10.10.3.2 255.255.255.128
end

I know the DHCP server is working because I have a 2960 connected to the WAN port of the UC520 and any phone plugged into the 2960 gets an IP address fine. Any ideas?

Fish!

This ought to take care of it:


no interface FastEthernet0/0.3

interface vlan3
ip address 10.10.3.2 255.255.255.128
no shut

interface FastEthernet0/1/0
switchport mode access



IP address 10.10.3.2 needs to be on interface vlan3 not on a subinterface on interface FastEthernet0/0. Also I think you need 'switchport mode access' on the switch port - otherwise it defaults to switchport mode dynamic desirable - a trunk - and the access+voice commands don't take effect until the mode is access.

EDIT: Oh, wait, I just noticed you have a switch hanging off of int f0/0.

OK, move the 2960 switch to one of the switch ports on the UC520 and create a trunk.

-OR-

Leave the 2960 on f0/0 and do IRB.


bridging irb
bridge 1 route ip

int fa0/0.3
bridge-group 1
no ip address

int vlan3
bridge-group 1
no ip address

int bvi1
ip address 10.10.3.2 255.255.255.128

Much more yucky, but it works.

snickered

I don't care what they say about you. You're a good man! I moved the trunk over to fa0/1/8(the "expansion" port) and removed fa0/0.3... worked like a charm. Thanks a lot. I don't even know what IRB is so I won't even attempt that method.

APA

your original config would have worked.....

should have encapsulation dot1q 3 without the native command on the fa port....

You obviously had that port hooked up to the 2960 as a trunk right??? So the native vlans would have been matching meaning all the 3 traffic would be untagged...... remember the native vlan traffic is always untagged with dot1q unless you tell it to be tagged...

Hence plugging a phone into the 2960 was working....