Actually what you ask is pretty easy. You can use what are called blacklists (do not allow these) and whitelists (allows only these) available in most firewalls. I'm not sure whether XP SP2 firewall has whitelists, but most of the freeware firewalls do have this facility.
There has been reports in the last few days of some user accounts being compromised and used for market section fraud. It is therefore recommended that you change your password immediately. Preferably you should also enable 2FA to be safe.