NTP protocol support in Cisco CSM module

Unanswered Question
Sep 5th, 2009

Can anyone plz advice if CSM module will support load balancing NTP traffic on the server ?

I have this problem too.
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Gilles Dufour Sun, 09/06/2009 - 00:21

there is no more development for the CSM.

So if this does not work today, it will never work.

Check the ACE module.


kashi_login Mon, 09/07/2009 - 16:44

Hi Gilles,

Sorry for the delay..and thanks for your update.

From you knowledge of the CSM module running on 4.2(2) ver,can you confirm if NTP protocol is supported for being load balanced. Bcoz i cannot see NTP under listed protocols supported by CSM.

Hence,was of the view it is not supported at all in current versions..as you ve already clarified that there is no development for CSM and hence there is no hope in future versions either.

Could you plz confirm this from your experience.

Gilles Dufour Tue, 09/08/2009 - 02:03

Basically we support all protocols based on UDP and TCP except a few of them like FTP over SSL.

So, NTP is probably supported.

We just can't list all protocols.


kashi_login Tue, 09/08/2009 - 04:29

that's what even i found out after going throught the documentation again.

But when i'm trying to timesync a network device by pointing it to NATd IP of CSM VIP(RIPs r setup as NTP server, i can see ntp traffic reaching real servers from the network device, but its not getting timesync.

Could there be any other reason preventing timesync to happen which is not visible upfront.


Gilles Dufour Tue, 09/08/2009 - 05:37

Here is what I would do to understand the problem.

Get a sniffer trace of NTP traffic without CSM.

Get another sniffer trace of NTP traffic when to the CSM.

Capture the trace on the CSM tengig interface.

Compare the 2 traces.

Check if NTP packet contains the server ip address.

See if there is no parallel connection being opened by the server to the client which would need to be nated.

If you get such a trace, you can send it to me for review.


kashi_login Tue, 09/08/2009 - 06:26

Here is what i see in CSM with ntp traffic reaching real servers

prot vlan source destination state




vs = NFTBZTKVIP, ftp = No, csrp = True

real = (n/a)

Could it be that..real servers not replying back to these ntp based packets or from your point what could be holding them back.

I will send you the trace once i pick them up.



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