IMessage authentication SMS Issues

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Tim Williams
New member
Username: Timw

Post Number: 47
Registered: 09-2010
Posted on Wednesday, October 23, 2013 - 05:00 pm:   

Hi,

We have noticed issues where the silent SMS sent through to activate IMessage/Facetime on the Iphone etc do not work - we are seeing them in the SMSIN logs as standard text SMS - as such when they get to the handset they just appear as a block of text.

Is this a known issue and/or any way to resolve it?
Des - NowSMS Support
Board Administrator
Username: Desosms

Post Number: 4701
Registered: 08-2008
Posted on Wednesday, October 23, 2013 - 06:36 pm:   

Hi Tim,

This suggests that some advanced attribute of the message is getting lost or corrupted somewhere during transit.

It could be when it passes through NowSMS ... but more likely it is an issue with one of the SMSC connections involved. Most likely a PID or DCS value getting modified (or perhaps UDH).

I assume the message is coming to you from an SMPP client connection (deliver_sm?) and then being routed to an upstream SMPP connection (submit_sm). It would be interesting to see the PID, DCS and UDH values recorded in SMSIN & SMSOUT. I am assuming they will be the same (and that the message data is the same in both).

But that's not to say that those values don't get changed before or after passing through NowSMS. There is a tendency for systems to ignore or discard unexpected PID or DCS values.

A Wireshark trace might be helpful.


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Des
NowSMS Support
Des - NowSMS Support
Board Administrator
Username: Desosms

Post Number: 4702
Registered: 08-2008
Posted on Wednesday, October 23, 2013 - 06:41 pm:   

I did a little more investigation.

PID and DCS may not be the issue. From what I've been able to gather, the most common source of this problem is source/destination address changes. Specifically for the message coming back from Apple, the phone needs to see this source address as matching the number that the phone sent the activation request to.

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Des
NowSMS Support
Tim Williams
New member
Username: Timw

Post Number: 49
Registered: 09-2010
Posted on Thursday, October 24, 2013 - 03:10 pm:   

Hi Des,

I found out it was the UDH not being passed through correctly - now resolved and working fine.

Thanks for the assistance.