Trends South Korea to Block Port 25 By Ken Simpson | 1 minute read Last week, according to the BBC, South Korea’s Internet and Security Agency began encouraging ISPs to block port 25 to limit the quantity of botnet spam emanating from the country. South Korea has long had a reputation as a haven for botnet spam, most likely because of the large number of Internet users in the country, and the extremely high quality and low cost of their broadband access. The recommendation to block port 25 will probably improve things in South Korea, if the ISPs get around to implementing this change. I’m not sure how influential the regulator is in that country, but if it’s like other developed countries, the ISPs are likely to drag their feet to avoid affecting users negatively.