DHCP and voip cisco 7910 settings

Posted on 2006-04-13
Last Modified: 2008-02-01
I have dhcp set up on the network. I need to set dhcp reservations for cisco voip phones. The reservations work, however, the router information needs to be inputted as well in order to reach the tftp server. Are there any options in the scope I can use to do this for the "default router 1" setting on the phone. I do have router in already for pcs but it wont push to the vopi phone either.
Question by:jbell72
    LVL 32

    Accepted Solution

    Ideally you should have them both in 2 Vlans. But anyways, don't you have default router configured in your DHCP scope? or is it that the voip phone won't accept it? What is happening?

    Can you explain a bit more on your setup?


    Author Comment

    Yes, I have the default router set up in my scope, all pcs take the router setting no problem. The voip phone takes all settings but the router info is left blank on the phone.

    Author Comment

    I am just wondering if the phone is rejecting it or just cant read it or something not sure.

    Author Comment

    I added 4 ips from each scope as interfaces on the router. They then were passed down to the phone via dhcp options. The ip of the router/gareway had to in the same range as the ip of the phone.

    Expert Comment

    There's some sample config from a working environment below. You'll also need to set up two DHCP scopes on your server, one for voice and one for data. Include the usual scope options such as DNS servers and Default Gateway.  You'll also need to configure the TFTP Server option (I'm assuming you're using a Windows DHCP server.) Full instructions on Configuring Windows 2000 DHCP Server for Cisco CallManager are at:


    interface FastEthernet0/0
     no ip address
    interface FastEthernet0/0.1
     encapsulation dot1Q 23
    description Data_VLAN_Default_Gateway
     ip address
    ip helper-address (!DHCP SERVER)
    interface FastEthernet0/0.2
     encapsulation dot1Q 13
    description Voice_VLAN_Default_Gateway
     ip address
     ip helper-address (!DHCP SERVER)


    interface FastEthernet0/5
     description To_Router
     switchport trunk encapsulation dot1q
     switchport mode trunk
    interface FastEthernet0/18
     description To_Phone_and_PC
     switchport access vlan 23
     switchport trunk encapsulation dot1q
     switchport mode trunk
     switchport voice vlan 13
     spanning-tree portfast
    vlan 23
    name Data_VLAN
    vlan 13
    name Voice_VLAN

    Hope this helps,


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