Incoming number display (SIP)

[WGAIT]

Thank you to everyone who helped on my previous post, I seem to unable to get that to work as I was expecting so maybe I'm looking at it from the wrong perspective.  I'm starting a new thread as I believe this may be a different question/solution.

We have a SIP trunk that has lots of different numbers pointing to it.  When we dial some of these numbers, the incoming call shows as it should (e.g. 01234 567890).

When we dial some of the other numbers, we get the 44 (e.g. 441234 567890)

I was hoping to be able to absorb the 44 and replace with a 0 but that didn't work out. 

We've run a Wireshark trace and can see that on the incoming calls that display the incoming caller ID fine, the SIP header reads as:

From: <sip:01234567890@sip.provider;user=phone>;tag=xxxxxxxxxxxxxx
SIP from address: sip:01234567890@sip.provider;user=phone>

But on the calls that show the extra 44 information, the SIP header reads as:

From: "+441234567890"<sip:01234567890@sip.provider;user=phone>;tag=xxxxxxxxxxxxxx
SIP Display info: "+441234567890"
SIP from address: sip:01234567890@sip.provider;user=phone>

So, in essence, it's adding a 'SIP Display info' line to the header, then using the information contained within that to populate the 'From' header also.

So, is there a way to ignore the 'SIP Display Info' field and just use the number displayed in the "sip:01234567890@sip.provider" part of the header?

[PC77375]

Did you happen to try "Prefer From Header for Caller ID" under Signaling and Header Manipulation in the SIP peer profile for that SIP trunk?

[WGAIT]

Hi, yes we've tried that and it doesn't make any difference.

[PC77375]

Are these different numbers coming in on the same SIP trunk?

[WGAIT]

Hi, yes it is, and all with the same supplier.  The issue is some numbers route via a different SIP server within the suppliers network but they are unwilling/unable to make any changes at their end as they say all their servers conform to the SIP standard (but they agree the numbers are being presented differently depending on which of their servers route which number) and it's down to us to amend our PBX accordingly.

[sarond]

I think one of my providers is doing the same.
I have attached screenshots of my options, I pretty much left everything at default.

[WGAIT]

Thanks for that, our trunks' SDP and Header options are the same as yours, the only difference is we have 'AVP Only Peer' set to 'No' and 'Avoid Signaling Hold to the Peer' set to 'Yes' under 'SDP Options'.

Under 'Signaling and Header Manipulation' we have 'Use To Address in From Header on Outgoing Calls' set to 'Yes'

Not entirely sue any of those would make any difference? Maybe the AVP Peer one?

The trunks themselves are in a Class of Service group, could that be causing a problem?  There are a set of display options in there.

[sarond]

I did think that but not sure.
I have attached what I'm using if you want to compare.