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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Appendix B Working with the Cisco IOS File System, Configuration Files, and Software Images
Working with Software Images
Preparing to Download or Upload an Image File By Using RCP
RCP provides another method of downloading and uploading image files between remote hosts and the
switch. Unlike TFTP, which uses User Datagram Protocol (UDP), a connectionless protocol, RCP uses
TCP, which is connection-oriented.
To use RCP to copy files, the server from or to which you will be copying files must support RCP. The
RCP copy commands rely on the rsh server (or daemon) on the remote system. To copy files by using
RCP, you do not need to create a server for file distribution as you do with TFTP. You only need to have
access to a server that supports the remote shell (rsh). (Most UNIX systems support rsh.) Because you
are copying a file from one place to another, you must have read permission on the source file and write
permission on the destination file. If the destination file does not exist, RCP creates it for you.
RCP requires a client to send a remote username on each RCP request to a server. When you copy an
image from the switch to a server by using RCP, the Cisco IOS software sends the first valid username
in this list:
• The username specified in the archive download-sw or archive upload-sw privileged EXEC
command if a username is specified.
• The username set by the ip rcmd remote-username username global configuration command if the
command is entered.
• The remote username associated with the current TTY (terminal) process. For example, if the user
is connected to the router through Telnet and was authenticated through the username command,
the switch software sends the Telnet username as the remote username.
• The switch hostname.
For the RCP copy request to execute successfully, an account must be defined on the network server for
the remote username. If the server has a directory structure, the image file is written to or copied from
the directory associated with the remote username on the server. For example, if the image file resides
in the home directory of a user on the server, specify that user’s name as the remote username.
Before you begin downloading or uploading an image file by using RCP, do these tasks:
• Ensure that the workstation acting as the RCP server supports the remote shell (rsh).
• Ensure that the switch has a route to the RCP server. The switch and the server must be in the same
subnetwork if you do not have a router to route traffic between subnets. Check connectivity to the
RCP server by using the ping command.
• If you are accessing the switch through the console or a Telnet session and you do not have a valid
username, make sure that the current RCP username is the one that you want to use for the RCP
download. You can enter the show users privileged EXEC command to view the valid username. If
you do not want to use this username, create a new RCP username by using the ip rcmd
remote-username username global configuration command to be used during all archive
operations. The new username is stored in NVRAM. If you are accessing the switch through a Telnet
session and you have a valid username, this username is used, and there is no need to set the RCP
username. Include the username in the archive download-sw or archive upload-sw privileged
EXEC command if you want to specify a username only for that operation.
• When you upload an image to the RCP to the server, it must be properly configured to accept the
RCP write request from the user on the switch. For UNIX systems, you must add an entry to the
.rhosts file for the remote user on the RCP server. For example, suppose the switch contains these
configuration lines:
hostname Switch1
ip rcmd remote-username User0