About Cisco 7985 series phones.

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May 1st, 2008
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We recently applied port-security in our network. Our security policy is maximum allowed mac-address per port is 2(1 for phone and 1 for pc). After that all ports which are connected to the 7985 phones goes down. We noticed that 7985 phones generating multiple mac-address when we making multiple calls from same line. We are using CCM4.2

Why it is happening?...Any one knows Let me know.


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Sushil Kumar Katre Thu, 05/01/2008 - 06:52
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This is a know issue with switches running OLD IOS. In those releases IP Phones uses two MAC address and one used by PC.

Thus you need to allow 3 MAC addresses per port 2 for phone and 1 for PC. Don't ask me why phone uses two mac I don't have any answer for that & I can't think of one.

You have two options either to upgrade the IOS or to allow 3 MAC addresses per port.

For a trial allow 3 macs on one of the interfaces with the phone and confirm that everything works after allowing 3 macs.

-> Sushil

Nahassamad_2 Thu, 05/01/2008 - 06:58
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Hi sushil,

Thank you for your response. I already tried this. Finally i found the phone showing upto 5 mac addresses.

arielroza Wed, 08/06/2008 - 10:40
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Did you resolve this issue?

Was it a particular phone, or was a general issue?

What did you do to solve it?



Nahassamad_2 Wed, 08/06/2008 - 21:56
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Thank you for your reply...It not solved yet. It seen all 7985 phones. I removed the porsecurity from the ports, which are connected to these phones.


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