Cisco7960 SIP 7.5 - IP address problem

Unanswered Question
Feb 5th, 2007

After phone boots it requests an IP address and gets and offer from DHCP server and then phone again requests it and Server Acknolwedges it(All normal according to DHCP protocol). But phone never assign itself the alloted ip address and goes through above procedure again and again.

I have seen all above using Ethereal packet capture.

What could be the problem?

/A

I have this problem too.
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Paolo Bevilacqua Mon, 02/05/2007 - 11:01

Please check that option 66 is present in the DHCP offer. If it is not, the phone behaves like you observed.

ajeetcisco Mon, 02/05/2007 - 14:07

But I am using built-in DHCP server in the router. As it is non-enterprise router so there is not anyway to define OPTIONS parameter in it.

But why it is like that? Since Cisco7960-SIP has option to configure SIP accounts directly on phone then why it needs TFTP server?

Apart from that I think some time back I tried with static address and it worked without any TFTP server. Any clues why it is working in static address mode without TFTP server when it does not work without TFTP server in DHCP mode.

I will come back with updates

Paolo Bevilacqua Mon, 02/05/2007 - 14:26

Hi,

what I reported comes from experience with a 7912. I do not have a 7960 to try right now.

Anyway, the DHCP request is made by the phone bootloader, not the firmware, or "phone load". And, when used with CCM and CCME, the phones indeed need TFTP, no matter if SIP or SCCP.

Finally, here is an example of router DHCP configuration that gives both option 66 and 150 to the phones. I don't know what you are using but I never heard of limitations because of the image used.

ip dhcp pool Telefoni-BWS

network 192.168.4.0 255.255.255.0

next-server 192.168.4.2

domain-name byworks.com

dns-server 192.168.5.4

option 42 ip 192.168.4.2

default-router 192.168.4.2

option 66 ip 192.168.4.2

option 150 ip 192.168.4.2

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