FTP Server Testing

In the process of working on a FTP Server demo, I find it helpful to use a lot of FTP clients that do NOT use one line of Indy Source Code.   I say this because I find that using some clients may expose FTP server bugs that you would miss with other clients.  This is particularly true with advanced FTP features that relatively new such as MODE Z, MLSD, some SITE commands, and SSL with FTP.  In addition, some clients might be buggy and you may have to work around those bugs (especially if the client is a popular one).  In testing the NcFTP client, I found where an extra 200 reply line was being sent with the reply to the "OPTS MLST" command and that was throwing off the client.  Finally, you get an opportunity to see some "de facto" practices that clients do so you can support them.

Our FTP server supports a number of commands that I've observed FTP clients use.  For example, older versions of FTP Voyager would get accurate file dates using the standard list command by getting a time-zone offset with a "SITE ZONE" command and then using a special "-T" switch that Serv-U FTP Server supports.  I was able to do the same thing with our server.  Recently, I found that NcFTP was sending a special SITE UTIME command to preserve file dates and I added code in our server to support this feature.   In Cute FTP Professional, I was able to see how the COMB command was used for multipart file uploads and I also implemented their XCRC command.  I tested secure FTP site-to-site transfers using the CPSV command by testing it with FlashFXP and then I tested our SSCN support using SmartFTP.  There are numerous other examples.

If you are curious, I test our FTP server component with the following clients:

• FileZilla
• FlashFXP
• FTP Voyager
• GlobalScape CuteFTP Professional
• NcFTP
• NFTP
• SmartFTP
• Ipswitch WS_FTP Professional 2006

I also have tested our FTP client component with RaidenFTPD server and BlackMoon FTP Server plus various FTP sites that I've lost track of.

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