RE: OT - CallManager and NAT

From: Haas, Brad (bhaas@netinfosys.com)
Date: Wed Nov 29 2006 - 19:13:12 ART


Here is more on that...

Looks like you may also need to specify your CCM using dns rather than
the ip.

Cisco's Skinny Client Control Protocol (SCCP) * Release 12.1(5)T

* Cisco IP Phone to Cisco Call Manager protocol

* To specify a port other than the default port, on which the CCM is
listening for skinny messages use the following command in global
configuration mode:

Router(config)# ip nat service skinny tcp port number

* SCCP client to CCM typically flows from "inside" to "outside", where
the Cisco Call Manager (CCM) is on the "inside" (behind the NAT device)
DNS should be used to resolve the CCM IP address to connect to.

* Cisco IOS NAT supports translation of DNS A and PRT records

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Vincent Mashburn
Sent: Wednesday, November 29, 2006 1:55 PM
To: Andi Bennett; ccielab@groupstudy.com
Subject: RE: OT - CallManager and NAT

You can configure NAT to translate the IP address in the SCCP payload by

using the following:

Ip nat service skinny tcp port 2000

Vince Mashburn

Sr. Voice / Data Engineer

901-263-5072

CCVP, CCNP

Cisco IP Telephony Support Specialist

Cisco IP Telephony Operations Specialist

-----Original Message-----

From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of

Andi Bennett

Sent: Wednesday, November 29, 2006 10:50 AM

To: ccielab@groupstudy.com

Subject: OT - CallManager and NAT

Sorry for the off topic here but this has me a bit stumped.

I have Cisco IP

Phones on the "outside " of the network connecting to a CM on the

"inside" of

the network.

Now, the phones can alternate TFTP to the CM, they then get an

image, but they the try and connect to the real addresses of the CM's,

which

is obviously unroutable on the outside.

I have

ip nat outisde source static

configured to get the phones to the CM. I think the problem is that the

return TFTP image has the embedded real addresses of the CM in it.

as a run

down of config I have

ip nat outside source static 10.18.192.10 172.27.10.1

(Publisher + TFTP server)

ip nat outside source static 10.18.192.11

172.27.10.2 (CM1)

ip nat outside source static 10.18.192.12 172.27.10.3 (CM2)

The phones get the image, then keep trying to connect tot he 10.18.192.x

addresses

I've looked at using the ip nat service port sccp command, but it

seems to have no effect as the phones still try to connect to the real

CM

addresses, not my staic NAT entries.

Is what I'm trying to do possible, or am

I barking up the wrong tree??

Any advice would be appreciated.

Cheers

Andy.



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