Faking a sender Number

[Stefan Schoeman]

Hi Guys,

Just wanted to get people's opinions on this.
How easy is it to fake the sender ID on an SMS message?
i.e to send an SMS which appears to be coming from a phone other than one's
own ?
I ask this not because I want to do it, but to assess to what extent one can
trust the
sender on a received SMS to truly report the number of the phone that it
came from.

Looking forward to a GSM guru's response on this.

Stefan