ip phone reboot

[leowchongwei]

Hi,

have a 3560 switch and the ip phone reboots sometimes... how can i find out the cause? the phone draws power inline and about 26 phones...

Thanks

[thisisshanky]

Is it the same phone that always doing this, or all phones reboot ? Try swapping the cable to see if that helps!! What messages on the phone do u get when it does so ?

[jaregalado]

Hi,

I think it would be very helpful if you configure an span port for your problematic IP phone an then sniff on that port so you can see if any particular traffic is the reason for this type of behaviour.

If you are using Skinny IP Phones then you should be seeing SCCP/TCP and RTP/UDP traffic most of the time.

I remember how a coworker managed to reboot an IP Phone on our lab just by crafting oversized ICMP packets targeted to the Phone, this is called a DoS (Denial of Service) attack in Network Security parlance, so definetely some bugs were present on previous IP Phone firmware versions.

Maybe a simple firmware upgrade may resolve your issue.

Regards.

[leowchongwei]

But i need to find out where is the problem first... The firmware, the switch, CCM ??? :(

[cmelbourne]

Hi,

We are having the same issues expcet that we are using alcatel ip phones with the cisco 3560 switch for inline power.

Did you manage to sort this out, what is all phones that were rebooting ?