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Community Member

Cisco7960 SIP 7.5 - IP address problem

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?


Hall of Fame Super Gold

Re: Cisco7960 SIP 7.5 - IP address problem

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

Community Member

Re: Cisco7960 SIP 7.5 - IP address problem

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

Hall of Fame Super Gold

Re: Cisco7960 SIP 7.5 - IP address problem


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





option 42 ip


option 66 ip

option 150 ip

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