When the School of Informatics was first formed, existing individual department services were kept running. One of those services was ftp.cogsci.ed.ac.uk. However over the years its functionality became less and less, and currently only allows public downloads of content that has not been updated in 10 years.
Looking at the logs the vast majority of connections are from Bots like GoogleBot. Given this, and a desire to close unnecessary firewall holes. The ftp service has now been shutdown.
If there was public content on ftp.cogsci.ed.ac.uk that should still be made available, then hosting it on a web page would be one alternative.