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Admin Alert: Modifying an OS/400 FTP Server Configuration
by Joe Hertvik
Like most OS/400 server programs, there are a number of configuration attributes assigned to your OS/400 FTP server that control its behavior. Each attribute is modifiable, and together they offer many benefits for controlling OS/400 FTP, including automatically starting your FTP server whenever TCP/IP is started, changing the initial number of FTP server jobs that are started, and changing the subsystem that your FTP servers run in.
FTP server attributes can be configured either through the green-screen Change FTP Attributes (CHGFTPA) command or through the FTP server properties option inside iSeries or Client Access Operations Navigator. This week's Admin Alert will look at how you can configure OS/400 FTP by using either function. (Note that the following examples are shown using OS/400 V5R1 and the Operations Navigator program that comes with Client Access Express for Windows V5R1M0. Many of the functions listed are available for other versions, but their location may be slightly different from what's described here.)
To view and change your FTP server attributes from the green-screen, type in the CHGFTPA command without any parameters and press the F4=prompt key. This brings up a command prompt screen, where your FTP attributes can be viewed and modified.
To view and change your FTP server attributes from OpsNav, open the Network-Servers-TCP/IP node inside the OpsNav tree and right-click the FTP server entry in the right-hand pane. On the pop-up menu that appears, click the Properties option. This brings up an FTP Properties screen, where your server attributes are listed under the following tabs that describe information about each group of OS/400 FTP parameters.
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The General tab shows attributes that specify how and where to start the FTP server and what job attributes and SSL settings should be used.
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The Mappings tab shows the current settings for your FTP server's ASCII coded character set identifier (CCSID) as well as the server's ASCII-EBCDIC mapping tables.
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The Initial Formats tab contains settings that tell OS/400 FTP how to set working directories and file-naming formats whenever a new user logs on to the server.
It's important to understand that the green-screen and OpsNav configuration options both modify the same FTP attributes, so they can be used interchangeably. The only difference between them is that the attribute values have slightly different names under each option. To better understand what each option is for and what it changes, here's a cross-reference listing of the more popular FTP attributes that can be modified under CHGFTPA or the OpsNav FTP tabs and what each attribute does.
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OpsNav Location Tab and Parameter Description
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CHGFTPA Parameter Name
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Parameter Function and Notes
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General Tab--Start when TCP/IP is started check box
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Autostart servers (AUTOSTART)
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A yes or no parameter (*YES, *NO, or an OpsNav check box) that tells OS/400 whether to start your FTP server jobs whenever TCP/IP is started through the Start TCP/IP command (STRTCP) with the following Start applications parameter (STRSVR) value:
STRTCP STRSVR(*YES)
STRSVR(*YES) tells TCP/IP to automatically start any TCP/IP server whose AUTOSTART value is equal to *YES.
Also note that, starting with OS/400 V5R1, the Start TCP/IP Server command (STRTCPSVR) added an *AUTOSTART option to its Server application parameter (SERVER). If you specify *AUTOSTART under STRTCPSVR's SERVER parameter, as follows, the command will start all TCP/IP servers that are configured for autostart.
STRTCPSVR SERVER(*AUTOSTART)
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General Tab--Initial number of servers to start (1-20)
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Number of initial servers (NBRSVR)
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A numeric value that specifies the number of OS/400 FTP server jobs to start whenever FTP is started through the STRTCP or the STRTCPSVR commands. This affects the number of active QTFTPxxxxx jobs running in your FTP subsystem (where xxxxx is equal to a unique number assigned by OS/400). For high-traffic FTP servers, additional server jobs can help increase throughput.
Note that you can increase your initial server value dynamically while OS/400 FTP is running, and when you increase this value the number of current server jobs will be increased the next time your iSeries or AS/400 accepts a new FTP connection.
Also note, however, that a decrease in this value has no effect on the current number of server jobs. A decrease in the number of startup FTP servers will be activated the next time you use STRTCP or STRTCPSVR to start FTP.
The shipped value is three servers.
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General Tab--Inactivity timeout
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Inactivity Timeout (INACTTIMO)
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A numeric value that specifies the number of seconds OS/400 will allow an FTP session to remain inactive before it's automatically ended.
The shipped value is 300 seconds (or 5 minutes)
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Initial Formats--File-naming format
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Initial Name Format (NAMEFMT)
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Specifies the initial setting of the FTP NAMEFMT subcommand (0 or 1) when a client starts a new FTP session on this iSeries or AS/400. NAMEFMT is used to determine the naming format that identifies file locations inside an FTP session. Possible values are:
1. Library/file.member or *LIB--This value defaults FTP sessions to a NAMEFMT 0 setting, where transfer locations are listed in the DB2 UDB library and file.member format (library/file.member). NAMEFMT 0 is only used for DB2 UDB transfers (inside the QSYS.LIB file system) between two iSeries or AS/400s. This setting cannot be used for any other Integrated File System transfer.
When running a NAMEFMT 0 session, the file syntax for specifying DB2 UDB location names is /libraryname/filename.membername. When the .membername part of the notation is eliminated, FTP automatically transfers the first member in a file.
2. Path or *PATH defaults new FTP sessions to a NAMEFMT 1 setting, where transfer locations must be listed in complete IFS notation, including the root (/) directory. During some OS/400 FTP transfers, NAMEFMT may automatically be set to 1 when a file outside the QSYS.LIB file system is listed in IFS notation.
When running a NAMEFMT 1 session, the file syntax for specifying DB2 UDB location names is /filesystemname/directoryname/ filename.extension for files residing in the root (/), QDLS, and QOpenSys file systems; /QOPT/volname/dirname/filename.extension is for optical files; and /QSYS.LIB/libraryname.LIB/ filename.FILE/membername.MBR is for DB2 UDB data.
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Initial Formats--Working directory
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Initial Directory (CURDIR)
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Specifies the initial FTP server working directory to use when a user logs onto the OS/400 FTP server on this machine. This attribute is equivalent to executing an FTP Change Working Directory (CD) command in the new session.
Possible values are:
Use user's current library or *CURLIB--New sessions use the current library specified in the signed-on user profile's Current library (CURLIB) parameter as the working directory. FTP uses the QGPL library if a CURLIB value is not specified. The file naming format attribute must be set to Library/file.member or *LIB to use this setting.
Use user's home directory or *HOMEDIR--Use the home directory location specified in the signed-on user profile's home directory (HOMEDIR) parameter. If no home directory is assigned to the user profile, OS/400 FTP will use the root (/) directory as the working directory.
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General Tab--Subsystem
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Subsystem description (SBSD)
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OS/400 V5R1 and above only
Specifies the subsystem description name and library of the subsystem your FTP server jobs will run in. When you start OS/400 FTP, all server jobs are assigned to this subsystem. Possible values are:
Use default (QSYS/QSYSWRK) or QSYS/QSYSWRK subsystem--Runs your FTP server jobs in the default TCP/IP subsystem QSYSWRK, whose subsystem description resides in the QSYS library.
A specific subsystem description name and library that is used to start your target subsystem. Enter an existing subsystem description location where you want FTP to run. If the subsystem description name doesn't exist, FTP will create a new subsystem description and job queue for your FTP jobs using default subsystem values.
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General Tab--Sockets layer support to be started with server
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Allow secure sockets layer (ALWSSL)
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OS/400 V5R1 and later only
Tells FTP whether it should accept SSL FTP sessions if SSL is already enabled on your iSeries or AS/400 and a valid FTP server certificate is configured. Possible values are:
Both secure and non-secure or *YES--Accept both SSL FTP sessions and non-SSL FTP sessions.
Non-secure only or *NO--The OS/400 FTP server will only accept non-SSL FTP sessions.
Secure only or *ONLY--Except for anonymous users, the FTP server will accept SSL-enabled sessions only.
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After you make your changes, click OK in OpsNav or press the Enter key on the Change FTP Attributes screen to save the changes. Some changes may not take effect until the FTP server is restarted.
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Editor
Timothy Prickett Morgan
Managing Editor
Shannon Pastore
Contributing Editors:
Dan Burger
Joe Hertvik
Kevin Vandever
Shannon O'Donnell
Victor Rozek
Hesh Wiener
Alex Woodie
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Advertising Director:
Jenny Thomas
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Kim Reed
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