I was called today by a person claiming that he was with BT. He claimed that my ip address had been changed by someone without authorisation from being a private ip address to a public ip address. He claimed that this meant that this rendered my devices being accessed by anyone. Hev proposed that I make some changes (unspecified) that would allow him to change some settings on a BT server that would make my ip address private again.
Is this a scam? Is there any truth in private ip addresses being safer than public ones?