[c-nsp] Cisco CMTS and ISC DHCP Strange Issue

[Jean-Francois.Dube at videotron.com]

Hi Rupesh,

I suggest you first make sure DHCP works properly for the affected CPE.

debug cable mac H.H.H
debug cable dhcp

These should allow you to see DHCP D.O.R.A. for a CPE with MAC H.H.H

The CMTS needs to use leasequery (RFC 4388) if you experienced an outage of
some sort to rebuild its internal database.

If leasequery option 13 is not working properly with ISC servers then you
may have this problem.

You could try removing "cable source verify" as a test.


Hope this helps.

Cheers,

JF

Jean-François Dubé
Technicien, Opérations Réseau IP
Ingénierie Exploitation des Réseaux
Vidéotron
"cisco-nsp" <cisco-nsp-bounces at puck.nether.net> a écrit sur 2014-05-24
09:17:37 :

> De : Rupesh Basnet <brupesh at subisu.net.np>
> A : cisco-nsp at puck.nether.net,
> Date : 2014-05-24 09:24
> Objet : [c-nsp] Cisco CMTS and ISC DHCP Strange Issue
> Envoyé par : "cisco-nsp" <cisco-nsp-bounces at puck.nether.net>
>
> Hi everyone,
>
> We have been using Cisco CMTS 7246 for about a decades. These days we
> are facing some strange issue with CPE IP assigned by DHCP. We are using
> ISC DHCP for both the modems and CPE. While I check modem searching for
> the particular modem only then CPE taken is seen 0 but when I check cpe
> with modem IP then I can see that customer CPE is taking IP address.
> While checking on CMTS, the arp taken by CPE arp is also seen but no any
> traffic are passing. If I bind the CPE mac and assign a IP then
> everything gets to normal.
>
> CMTS is configure to relay on two DHCP services running on fail over
> mode and soure verification is done for all the addresses.
>
> cmts2#show cable modem | in 814c
> 00e0.6f70.814c 10.28.114.242   C3/1/U0   online       157   0.00 1942 *0
> *  N
>
> cmts2#show cable modem 10.28.114.242 cpe
> IP address        MAC address
> *10.34.16.12      9061.0c15.2535 *
>
>
> --
> Regards,
> --------
> Rupesh Basnet
>
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