[ Date Index ] [ Thread Index ] [ <= Previous by date / thread ] [ Next by date / thread => ]
On 09/05/2022 15:46, Giles Coochey wrote:
My land-line has a facility to block numbers which can be pointless if they change every time. Unfortunately legitimate callers such as hospitals and District Nurses withhold the number they are calling from, so I have no choice but to answer withheld calls. Then use my grey matter to judge if they are legitimate or not.On 09/05/2022 15:33, Julian Hall wrote:A lot of the time they don't use SIM cards at all, they just use VoIP SIP gateways in foreign countries. Via SIP they can manipulate the caller-id to any number they want. And it is possible that they might use a strategy to use an area code that would look familiar to the receiver.The only problem is that scammers are becoming more sophisticated and bulk buying SIM cards so call from different numbers. Also they've developed a nasty habit of calling from the same dialling code as they call, so it looks like a local caller. However the general rule is if in doubt ignore it. If it's genuine they'll call again and/or leave a message.I recall some talk in the press over the last few months to have mobile phone networks restrict / block VoIP caller-ids which are obviously incorrect, but it is not particularly easy. It is very easy to get legitimate geographic UK numbers over the Internet, and the SIP trunks are very often cloud based, which means they could be hosted anywhere.
Julian -- “The great tragedy of Science — the slaying of a beautiful hypothesis by an ugly fact.” ― Thomas Henry Huxley -- The Mailing List for the Devon & Cornwall LUG https://mailman.dcglug.org.uk/listinfo/list FAQ: https://www.dcglug.org.uk/faq/