I have an EC2 instance that is setup as an SFTP server using OpenSSH. It only allows connections on whitelisted IPs via TCP Port 22 (limited via an EC2 Security Group). I constantly have customers try to connect from other IPs that they have not been whitelisted. I'd like to track those attempted connections and the IPs they come from so I can help them figure out their IP addresses.
Is it possible to see these IP addresses from the server? Can I also see the connection attempt and get the SFTP username?