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This chapter describes the TFTP service and how to:
For information on starting and stopping the TFTP service, controlling access, and modifying basic information and communication options, see the chapter titled "Configuring Services with the Service Configuration Manager".
The TFTP service uses the Internet-standard Trivial File Transfer Protocol (TFTP) to perform file transfers. TFTP can transfer files between the local host and remote hosts, but cannot perform operations other than file transfers, such as directory listings, file deletions, and so on.
Typically, TFTP is used to load software and configuration files to a network device. For example, Cisco routers use TFTP to load new versions of IOS and configuration files.
TFTP does not perform any authentication when transferring files, so a username and password on the remote host are not required. In general, only files with world-read access in certain directories on the remote host are available for reading, and only certain directories on the local host are available for writing.
The TFTP service normally requires full path names; however, systems that do not provide full path names can access files under the default TFTP directory. The default TFTP directory provided is MultiNet/tftp in the directory in which you installed the CDDM or Cisco Server Suite 1000.
To specify a different default directory:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Click on the checkbox next to the Default-tftp-directory label.
Step 5 Enter the default directory in the Default-tftp-directory field.
Step 6 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
Different operating systems, such as UNIX and Microsoft Windows, use different file and directory name conventions. You can configure the TFTP service to translate file and directory names from one format to another.
To set up file name translation rules, you define a Match spec, which is the file or directory name request you expect from a client, and pair it with a Translation spec, which is the corresponding file or directory on the local system.
Some sample translations are:
| Match Spec | Translate Spec |
|---|---|
| \doc\prog.dat | /doc/prog.data |
| \mystuff\*.* | /home/usr/mystuff/* |
The first example translates a single file. If a request for the file \doc\prog.dat comes from a DOS or Windows system, the TFTP service, which in this case is running on a UNIX system, translates the request to the file /doc/prog.data. In the second example, a request for any file from the directory \mystuff is translated to the directory /home/usr/mystuff.
To configure the TFTP service to translate file and directory names:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Enter the file or directory specification you expect to receive from the client in the Match Spec field.
Step 5 Enter the corresponding file or directory specification on the local host in the Translate Spec field.
Step 6 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
You can also use name translations to restrict access to your system. If you select the Restrict-access option, the TFTP service grants access only to the files and directories listed in the Translation rules or to files in the default TFTP directory. The default is to not restrict access.
To restrict access for a file or directory that does not need translation, list the same specification in both the Match spec and the Translate spec.
 | Caution If Restrict-access is not enabled, all world-readable files are available to TFTP clients. If files are not read-only, they can be overwritten. |
To restrict access to files and directories to those specified in the Translation specs and those in the default TFTP directory:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Check the Restrict-access box.
Step 5 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
When the TFTP service receives a request to transfer a file, it responds to the request by sending an acknowledgment. If the remote host does not respond to the acknowledgment by sending a request for the first data block in a specified amount of time, the TFTP service times out and closes the connection. The default value is five seconds.
To specify the amount of time the TFTP service waits after sending an acknowledgment before it times out:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Click on the checkbox next to the Tftp-Ack-Timeout label.
Step 5 Enter the number of seconds to wait before the service times out after sending an acknowledgment in the Tftp-Ack-Timeout field.
Step 6 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
The TFTP service uses a memory buffer to store data during a file transfer. The default buffer size is 4 KB.
| Caution Do not change the value of this parameter unless instructed by a Cisco customer support engineer. |
To change the size of the TFTP buffer:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Click on the checkbox next to the Tftp-Buffer-Size label.
Step 5 Enter the size in bytes of the TFTP buffer in the Tftp-Buffer-Size field.
Step 6 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
If the TFTP service stops receiving data requests during a file transfer, it waits a specified amount of time and then closes the connection. The amount of time the service waits is called the dead-transfer timeout. The default is 30 seconds.
To specify the length of time to wait before a dead-transfer timeout:
Step 1 Start the SCM.
Step 2 Choose TFTP from the Available Services box.
Step 3 Click on the Config tab.
Step 4 Click on the checkbox next to the Tftp-Dead-Transfer-Timeout field.
Step 5 Enter the number of seconds to wait before the service times out during a file transfer in the Tftp-Dead-Transfer-Timeout field.
Step 6 Choose Save Configuration from the File menu.
Changes take effect after you stop and restart the TFTP service.
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