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Home > Success Center > Serv-U Managed File Transfer & Serv-U FTP Server > 536 FTP response code

536 FTP response code

Updated May 3, 2017


This article provides information on 536 FTP response code.


All Serv-U versions


A 536 response code may be sent in response to a PROT command when the requested protection level is unsupported by the current security mechanism. It is a permanent negative response, which means the client is discouraged from sending the command again since the server will respond with the same response code. Negotiating a different security mechanism using the AUTH command can result in a different response code.

Example response

536 Requested PROT level not supported by mechanism.

Possible command




Last modified
20:40, 8 May 2017