SIP REFER w/ Exchange UM

[nickp]

Hello,

I am trying to forward a call using using SIP REFER but am getting a 603 error message.

I do this when an incoming fax is sent to our Exchange UM server.

The exchange server then sends back a SIP REFER message to the ICP3300 to send the call to our SIP Fax Server.

However the 3300 responds with a 603 Decline failure message.

I have attached a packet trace of the entire conversation.

Any help on getting the 3300 to forward this call would be appreciated.

Nick

[v2win]

A couple of questions

Since you are receiving it at your exchange server why are you redirecting it to a fax server cant you already see it in your email?

Can you send it directly to the fax server from exchange bypassing the 3300?

Can you call the fax number from the 3300 to the fax server?

Can you send it to an analog fax on the 3300?

[nickp]

Exchange 2010 UM doesn't have native fax capabilities.

Instead it relies on a partner fax server that it redirects faxes to.

I can't send it directly as the fax calls all need to originate from the 3300 and be forwarded to exchange w/ DIVERSION headers (just like voice mail). 

The SIP fax server does dot have a number assigned to it, only a SIP URI that exchange is configured to transfer the calls to.  It is only configured as a SIP peer on the 3300.

Do I need to configure a number/ARS Route for it and then perform URI/Number translation for it?

I can send faxes to analog ports directly from the 3300, but Exchange 2010 UM requires a SIP fax server to handle the calls.

The main issue is why the 3300 will not forward the call to the URI in the SIP REFER field.

[v2win]

I am assuming you modified the pcap so we dont have the CEO fax number? 

[nickp]

Hex editors are useful. 

[v2win]

Did you try the number to URI translation in the 3300?

[nickp]

I did; I assigned an extension to the SIP fax server and tried that. It didn't work.

When doing that I did see that from a phone if a dialed that extension it would place a call through to the FAX Server.

[smarbar]

Does the play on phone feature in Exchange work using both the extension number and DID?

[nickp]

Play on phone only works with extensions.

[smarbar]

Ok, sounds like you will need to sort a couple of things out. Firstly the Trunk Attributes assigned to the Exchange Sip peer profile is not abosobing/inputting any digits when the one assigned to your public trunks is, probably best to assign an extension number to your Fax server and refer to that. Secondly SIP peers are seen as public trunks to the system, so when you try to use refer you are actually asking it to transfer externally, so check that the class of service assigned to the Exchange peer profile (and/or possibly the public trunks?) is allowed to transfer externally.

[nickp]

I looked at the trunk attributes of the PRI Trunk and the Exchange SIP; Neither are absorbing or inserting any digits.

I have an extension assigned and tried referencing the fax server that way but exchange server complained and said:

Error:
sip:555@faxserver.domain.local:5060;transport=udp does not match the required format "sip:FQDN:port;transport=TCP/UDP/TLS". Example: "sip:fax.contoso.com:5060;transport=TCP"

On the COS of the Exchange peer profile and PRI I have:
Public Network Access via DPNSS
Public Network to Public Network Connection Allowed
Set to YES

My PRI COS is set as Public Trunk YES,
while the COS on Exchange is Public Trunk NO,

Are there other COS settings I am overlooking to allow for external transfers?
Maybe Call Forwarding (External Destination)?

Thanks

Nick

[nickp]

I tried play on phone again, and it does work with the full 10 digit DID and 10 digit external numbers.

It doesn't work with 7 digit DID's (As defined in System Speed Calls).