Why country filters are not effective
Country filters used to be effective around 10 years ago, when spammers would host their own email server to send out junk messages. Nowadays, the country filter is not effective for the following reasons:1. Instead of spammers hosting their own email server, they hijack legitimate email servers all over the world and then send spam messages to other servers. Because of this, it is possible for spam messages that appear to be coming from another country are actually coming from your own country
2. IP addresses change all the time. Since the addresses change quite frequently, the database needs time to keep up with the new addresses. This makes the country filter be inaccurate.