@ottosykora

In my opinion, this is a Swisscom problem because the call goes to the Swisscom headquarters and is blocked somehow, which shows that it works on the cell phone.

At least in a test last year it still worked??

It’s best to ask for help below.

https://www.swisscom.ch/de/privatkunden/hilfe/kontakt.html

@ottosykora

If all Swisscom landline numbers are affected, there is probably a problem with the Skype <> Swisscom landline gateway.

Since we in the “Customers Help Customers” forum are only customers like you and therefore do not have access to these systems, you have to contact support, preferably from both providers (Swisscom + Microsoft). If anything, you have to be a little stubborn and demand that the case be escalated to the 2nd level, because in a first step Swisscom will probably say that the problem is with Microsoft and Microsoft will say that the problem is with Swisscom.

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@ottosykora wrote:

everything worked normally until the end of August. No more from 9/1/22

I contacted support, unfortunately they don’t know anything about it and can’t help.

That’s why I’m asking here 😉

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@ottosykora

Then you have to be persistent and demand that the case be escalated to 2nd level support. If you open a problem ticket with Microsoft at the same time, there is also a chance that Swisscom will also come under pressure from this side.

From experience, such cases where several companies/providers are involved are very difficult because everyone passes the ball to the other. The only thing that helps is a lot of patience and persistence.

hed

This is how it works for me now, I had to adjust the image below in Kundencenter.

But there is now a danger that I could receive anonymous calls and therefore spam telephones.

@WalterB

Yes, that could be a direct hit, I’m looking forward to the answer from @ottosykora.

Since filters/blockers can unfortunately always have undesirable side effects, I generally avoid using them (example: ad blockers in the browser 🙂

hed

Strangely enough, when you call with Skype, no number is displayed to the person you’re calling and you can’t activate it in Skype?

@WalterB

Caller ID display, ring tones and other features are always “problem children” with the various VoIP providers, not just with Skype.

@ottosykora

I would allow anonymous calls anyway, i.e. turn off all relevant filters.

I initially used these filters, but there were always important calls that couldn’t reach me because, for example, certain VoIP services don’t transmit the phone number or the users don’t know how/where they can activate it or there are incompatibilities or errors at the sender where the number was temporarily not transmitted. In addition, there are still companies that deliberately suppress the number, including individual banks, law firms, doctors and hospitals.

hed

I stumbled across a new option in the cockpit of my Swisscom cell phone that I had seen for the first time, which perhaps explains why a Skype call can get stuck in the filter for anonymous calls.

So far it’s just a thesis:

In order to prevent fraud using the spoofing method as much as possible, Swisscom monitors the landline network to ensure that when calls are received, the number displayed matches the origin of the call.

Scenario A) The following applies if the “Block calls without originating number” option is NOT activated in the Callfilter settings:
If a call “from India” arrives and the transmitted caller ID is a CH landline number, then the call will be forwarded to the telephone from the Swisscom headquarters WITHOUT specifying the phone number , the status “unknown” should also be displayed on the phone. The call should also be displayed in the call list without a phone number and the status “unknown”.

Skype and scenario A) If a Skype call is forwarded to a landline customer via Swisscom, this takes place via a gateway from Skype to Swisscom. I assume that the caller ID monitoring described above would show most calls as “unknown” unless special countermeasures are taken for the gateway (for example for the gateway’s phone number). Error??? I suspect that, for example, the gateway’s phone number changed at the beginning of September and that previous countermeasures are no longer effective - New: Skype calls that are transmitted through Skype with caller ID , are currently mostly marked as “unknown” at Swisscom headquarters. If the gateway happens to be connected to the same network area as the landline telephone, then the phone number could also be correctly transferred from Skype to Swisscom.

Scenario B) The following applies if the “Block calls without originating number” option is ENABLED in the Callfilter settings:
If a call “from India” arrives and the transmitted caller ID is for a CH landline number, then the call will not be forwarded to the telephone from the Swisscom headquarters. From the descriptions in this thread I read that the callers receive the following feedback: “The participant does not want to be disturbed”

Walter

Addendum:

Section Skype and Scenario A): Explanation added at the end, from New:…

Also: previous last section deleted (“To be clarified regarding scenario A:”).
The process descriptions in article 25 show that calls that were recognized as “unknown” at the Swisscom headquarters are not also marked as “anonymous”.

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WalterB wrote:

@ottosykora @hed

Strangely enough, when you call with Skype, no number is displayed to the person you’re calling and you can’t activate it in Skype?

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@WalterB

This is normal, in this case the local number does not mean your phone number, but the local Skype number. You can get or purchase them like this (note: these are special numbers from UPC):

Get a local phone number and answer Skype calls from anywhere | Skype

If this number is entered in Skype, the switch is no longer grayed out.

@WalterB @ottosykora

For me, Skype behaves as follows when calling a landline number:

Call ID deactivated in Skype: Call works, is displayed as anonymous

Call ID activated in Skype: Call works, is displayed as unknown

In Wireshark it looks like this (target PhonerLite with local SIP credentials):

If you subscribe to a local Skype number and activate “Show local number” in Skype, this number will probably be displayed correctly. Since I don’t have a local Skype number myself, I can’t test this.

In my opinion everything is working correctly. In the first case, with the ID switched off, it is logically an anonymous call and in the second case it would be spoofing because I have stored my mobile number as the ID in the MS account. In this case, Microsoft will probably remove the wrong number and the call will be transmitted without a number (hence unknown/unavailable). This also explains the different spoken texts if you have activated the “Block anonymous calls” and “Block calls without an original number” filters on your landline.

@hed Thanks for the process description:

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@hed wrote:

… For me, Skype behaves as follows when calling a landline number:

Call ID deactivated in Skype: Call works, is displayed as anonymous

Call ID activated in Skype: call works, is shown as unknown…

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I have subsequently adjusted my post 23.

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@hed wrote:

…In my opinion everything is working correctly. … in the second case there would be spoofing because I have stored my mobile number as the ID in the MS account. …

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The gateway uses spoofing to transmit your mobile phone number to the Swisscom headquarters as caller ID instead of the gateway’s phone number. I don’t think Microsoft doesn’t do it that way anymore.
See my post 23: I suspect that, for example, the gateway’s phone number changed at the beginning of September, Swisscom should now react to this and ensure that the Swisscom headquarters continues to stop monitoring the gateway for spoofing (in mentioned in my post as: “countermeasures”).

Walter

@Walter_Wp

I tend to assume that Swisscom deliberately installed this spoofing protection. My guess is therefore also in the direction of the post by @Werner in post #21.

If Swisscom removes the phone number if spoofing is suspected, you can influence such calls using the setting in the call filter. Of course, you could add another point to the call filter (spoofing allowed), but that would only confuse customers and bring no additional benefit.