Information

On the Information page, basic information about the command is shown along with a link to more information on the Serv-U website. The command can also be disabled by selecting the Disable command option here. Disabled commands are treated as unrecognized commands when received from a client.

Message Files

Certain FTP commands allow a message file to be associated with them. The contents of a message file are sent along with the standard FTP response. In addition, a secondary message file path is available as a default option. This allows for message files to be specified using a path relative to the home directory of the user for the Message File. If the first message file is not found, Serv-U attempts to use the Secondary Message File instead. By specifying an absolute file path in the secondary location, you can ensure that each user receives a message file.

Managing Recursive Listings

Serv-U supports recursive listings by default, allowing FTP clients to obtain large directory listings with a single command. In some cases, clients may request excessively large directory listings using the -R parameter to the LIST and NLST commands. If performance in Serv-U is impacted by users requesting excessively large listings, recursive listings can be disabled by using the Allow client to specify recursive directory listings with -R parameter option.

Advanced Options

Some FTP commands contain advanced configuration options that offer additional ways to configure the behavior of the command. Where available, the configuration option is described in detail. The following FTP commands contain advanced configuration options:

• LIST
• MDTM
• NLST

FTP Responses

Global FTP responses are responses shared amongst most FTP commands, such as the error message sent when a file is not found. Customizing a global FTP response ensures that the response is used by all other FTP commands rather than having to customize it for each individual FTP command. FTP command responses can contain special macros that allow real-time data to be inserted in to the response. For more information, see System variables.

Message File

The server welcome message is sent in addition to the standard "220 Welcome Message" that identifies the server to clients when they first connect. If the Include response code in text of message file option is selected, the 220 response code begins each line of the specified welcome message. To customize the welcome message, enter the path to a text file in the Message File Path field. Click Browse to select a file on the computer. Serv-U opens this file and sends its contents to connecting clients.

The following options apply to the FTP protocol in general:

Block "FTP_bounce" attacks and FXP (server-to-server transfers): Select this option to block all server-to-server file transfers involving this Serv-U File Server by only allowing file transfers to the IP address in use by the command channel. For more information about FTP_bounce attacks, see CERT advisory CA-97.27.

Include response code on all lines of multi-line responses: The FTP protocol defines two ways in which a multi-line response can be issued by an FTP server. Some older FTP clients have trouble parsing multi-line responses that do not contain the three-digit response code on each line. Select this option if your clients are using an FTP client experiencing problems with multi-line responses from Serv-U.

Use UTF-8 encoding for all sent and received paths and file names: By default, Serv-U treats all file names and paths as UTF-8 encoded strings. It also sends all file names and paths as UTF-8 encoded strings, such as when sending a directory listing. Deselecting this option prevents Serv-U from UTF-8 encoding these strings. When this option is deselected, UTF-8 is not included in the FEAT command response to indicate to clients that the server is not using UTF-8 encoding.