external FTP monitor via explicit FTP proxy

Dear all,

I have a couple of forward proxy servers load balanced behind the F5 and we are wondering how to monitor the FTP proxy services, so basically we are looking for a way to send a FTP command via an external explicit FTP proxy just like we do with http curl command for web services (see below). Does someone have a solution to monitor FTP via explicit proxy?

curl -k -v ${URI} --proxy ${IP}:${PORT} --http1.1  2>&1 | grep -i "${RECV}"