Inbound international SMS unblocked

Forums › 2degrees (including Slingshot, Orcon, Flip, Stuff Fibre, MyRepublic, 2talk and Vocus) › Inbound international SMS unblocked

arnies

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#317516 23-Oct-2024 10:50

I switched from 2Degrees to Contact (VF) the other week and today I noticed my SMS 2FA wasn't coming through from IBKR.

I stumbled upon some threads here that mentioned typing blocking codes into your phone, so I had a search and found https://medium.com/@mosesgrey/how-to-turn-on-or-off-the-call-and-sms-blocking-feature-in-your-phone-85b527107d54 .

I entered the codes for blocking/unblocking incoming calls and SMS. Then I tried the SMS again and it worked instantly, which was unexpected.

How to block every incoming call.
Dial the following service code to block all incoming calls to your line: *35*0000#.

To stop all incoming calls to your line from being blocked, use the service code #35*0000#.

How to block all SMSs that arrive.
Dial the following service code to block all incoming SMS to your line: *35*0000*16#.

Dial the following service code to stop blocking all incoming SMS on your line: #35*0000*16#.

My question is why would I have to do this? I don't know enough about what this does under the hood but it seemed to fix my issue.

KiwiSurfer

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#3300449 23-Oct-2024 11:35

May be a red herring. I suspect some websites use different SMS providers so if you click 'Send again' it sends it via a different provider which then works. I've had several experience of the first SMS not working but the second SMS working without changing any settings on my end. The fact I sometimes get the same type of 2FA messages from different numbers seem to point towards this as well.

Another possibility is your recent port. Sometimes it takes a while for the system to update -- in my experience the first few days or weeks after a port, I've found international SMS is hit and miss.

Linux

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#3300518 23-Oct-2024 15:02

@arnies Not related the settings you are playing around with etc.... You have recently ported and it may take some time for the incoming SMS to arrive from 3rd partys such as IBKR

SMS Routing tables take time to update

arnies

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#3300525 23-Oct-2024 15:14

I agree with this all happened with such timing that I find it hard to be completely coincidental.

Ported the number a week or two ago.
Was attempting to receive code from IBKR today including phoning support over a time of ~2hrs. Many SMS sent, zero received.
Did this trick above after hanging up with IBKR
Attempted SMS again via IBKR and received it instantly.

So perhaps routing tables got updated between the 5 minis of me being on the phone with IBKR and me trying this technique .. but that would be insane timing.

Linux

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#3300526 23-Oct-2024 15:17

So SMS are now inbound to your MSISDN from IBKR?

KiwiSurfer

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#3300529 23-Oct-2024 15:20

Still seem most likely to be unfortunate timing. Whenever I've had issues with SMS 2FA it's always come right by itself without any intervention from myself. Most of the issues I've had over the years have been within a week or two after a port (which I do every year or so to chase better prices).

The description of the codes also show it would block or unblock all SMS -- so would not affect whether a SMS is coming from a domestic or international source. Did you test with SMS to a NZ number before using those codes? If SMS was working fine to NZ numbers it would point to as Linux says a routing issue affecting SMS from international sources.