[c-nsp] Strange IOS as DHCP Client behevior

Peter Rathlev peter at rathlev.dk
Sun Sep 21 18:18:16 EDT 2014

On Sun, 2014-09-21 at 23:35 +0200, Robert Hass wrote:
> My problem is that these routers are visible in DHCP binding database with
> very strange MAC:
>           0063.6973.636f.2d30.    Dec 20 2014 11:44 AM
> Automatic
>                     3035.302e.3536.6138.
>                     2e34.6132.622d.4769.
>                     302f.30
> Do you have idea why MAC is so weird ? Rest clients - Eg. Linux or Window
> boxes MACs is displayed correctly.

It's not a MAC address, it's a client identifier. And IOS by default
chooses a text string as client identifier. In your case it's:


> Anything to configure at Cisco clients to have proper MAC in binding
> database ?

The above example is completely proper. I'm not aware of any method for
making IOS not use a client identifier, but you can change the
identifier it sends via e.g. "ip dhcp client client-id ..." interface


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