Trivial File Transfer Protocol (TFTP) Server
TFTP is used to load different images on the security devices. You may be able to install or upgrade IOS, PIX, and Firewall Services Module (FWSM) images from these servers. A very popular and free TFTP server can be downloaded from the following location: http://www.solarwinds.net/Tools/Free_tools/TFTP_Server/
It is important to have the TFTP server loaded and ready, because it may be needed at any time.