Caller ID spoofing

Some people probably know that it is possible to display a different telephone number to the called party. (
Wouldn’t it be helpful if you could have the network provided number displayed next to the user provided number(CLIP) if they differ?

Hmmm, which of the types of spoofing could be detected like this?
…and wouldn’t cellular already be immune when there isn’t a malicious exchange involved?

According to this, CLIP looks like a generic name for Caller ID, so what specific mechanism are you thinking about?

CLIP (calling line identification presentation) in conjunction to CLIR (calling line identification restriction) are used to control the displaying of the caller ID when calling or being called.
This is done by the network (voice switch). The spoofing is not possible outside of the network operations layer.

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Sorry, I’ve been quite busy the last few days. Thank you for your responses.
I don’t have much experience with this topic and am thankful for every input. At my company we are using a SIP Trunk and I could manipulate the outgoing number so that on my sfos device the false phone number was displayed.
Maybe the behaviour is different in every country. You could call someone using a number of a bank, governmental service, etc. and demand some information. Probably it would be possible to be displayed as one of your contacts if the numbers match. I didn’t give that a try. Maybe you can even bypass apps like

Well, it’s often used when forwarding calls so it probably makes sense your SIP trunk allows that.
And yes, it’s common to send out both, a “user provided, not screened” number plus a “network provided” number.

Yes, until now I thought you would have to validate all the numbers you want to send via your trunk. There is at least one provider where you can send whatever you want. I could use mobile numbers which are in my contacts and sfos shows that this contact is calling. It worked on an android device too. I don’t think it would be too hard to show the network provided number too, if they differ.