Restricting access to ftpd

Whether the ftp daemon is in use or not on a Linux host, it’s a good idea to restrict the system user accounts from using it. Any user ID that is in /etc/passwd that is not permitted to use ftp should be copied to /etc/ftpusers. The following commands for Ubuntu create the file with a list of all users.

sudo awk -F”:” ‘{ print $1 }’ /etc/passwd | sort > ~/ftpusers

Edit the resulting ~/ftpusers to remove the IDs that are allowed to use ftp.

sudo nano ~/ftpusers

Then move the file from your home directory to /etc.

sudo mv ~/ftpusers /etc

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