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Phone MAC Not reaching router

Hi All,

I have came across a very weird issue.

Router>switch-A>switch-B>cisco phone[7941]

The phone connected on switch-B is not picking the IP address from the router. We can see the Phone mac up-to switch-A but nothing on the router at all. 

I have cleared the mac-address table for the phone on both switches. Defaulted the port. Shut it. reconfigured just for voice vlan. unshut. still mac only shows upto switch-A. Ran a debug for DHCP no activity or request from the phone at all. nothing in the router ARP

There are other phones on the switch B which are working fine. 

Is it a faulty phone or some other issue. Any help highly appreciated.

VIP Gold

The DHCP server is in the

Is the DHCP server in the same subnet as the phone? If not, you need to use  ip helper-address command for the phones to find the DHCP server in the other subnet.



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as a test configure DHCP on

as a test configure DHCP on the router with option 150 and run a span port the access port the phone is connected to to the switch and see if you can pich up a DHCP request using wireshark. then move up and span the link between switch and router.

also check the phone;s settings and see if there isnt a static IP configured on it.

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