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Troubleshooting FTP Site-to-Site Transfer

If you see any of the following error messages when you attempt to transfer files between two remote hosts, the sending or receiving server may not be configured to support this feature:

  • 500 Illegal PORT command

  • 501 IP address for data destination does not match client's

  • 425 Can't open data connection

  • 502 PASV command not implemented by this server

When the FTP Client encounters this problem, it attempts to transfer to the local PC, and then to the target site, after the error is received. Note that even though the transfer may complete successfully, you will see the error message before the transfer is completed.

If you regularly transfer between servers that don't support direct site-to-site transfer, you can configure the FTP Client to force all site-to-site transfers to copy files first to the local machine then to the destination server. This configuration allows you to transfer between sites without seeing one of the error messages listed above.

To force all site-to-site transfers to copy files first to the local computer

  1. From the Tools menu, choose Options .

  2. On the Preferences tab, select Force site to site transfers through local machine , and then click OK .

Review the following for more information about configuring servers to support direct site-to-site transfer.

Sending server configuration

Site-to-site transfer feature requires that any FTP server sending a binary file must accept a PORT command from the Reflection FTP Client to an IP address that is different from the client's IP address. (On some servers this support may be disabled for security reasons.) The PORT command specifies the TCP PORT to which the data should be sent. If the sending server does not accept this use of the PORT command, you will see two server error messages: usually a "500 Illegal PORT command" or a "501 IP address for data destination does not match client's" from the sending server, followed by a "425 Can't open data connection" from the receiving server. You will also see a file of zero bytes created on the receiving server because the file index is created prior to receiving any data. To enable site-to-site transfer, contact the administrator of the sending server to determine whether PORT commands to a different IP address can be enabled on the server.

Receiving server configuration

Site-to-site transfer requires that any FTP server receiving a binary file must accept a PASV command from the Reflection FTP Client and return the PORT information to be passed on to the sending server. If the receiving server does not accept the PASV command, the site-to-site transfer will fail with an error message: "502 PASV command not implemented by this server". To enable site-to-site transfer, contact the administrator of receiving server to determine whether PASV can be enabled on the server.

More information