In this story we showed how to upgrade IOS on a Cisco using a TFTP server available from Cisco that ran on Windows. Well, just suppose you wanted to load a new IOS image from a TFTP server on a GNU/Linux box. We will use Red Hat 8.0 to provide a TFTP server.

First, install the RPM:

# rpm -i /usr/local/80rpms/tftp-server-0.29-3.i386.rpm

Edit /etc/xinetd.d/tftp:

service tftp
{
socket_type             = dgram
protocol                = udp
wait                    = yes
user                    = root
server                  = /usr/sbin/in.tftpd
server_args             = -s /tftpboot
disable                 = no
per_source              = 11
cps                     = 100 2
}

Restart xinetd:

[root@srv-1 cisco]# /etc/rc.d/init.d/xinetd restart
Stopping xinetd:                                           [  OK  ]
Starting xinetd:                                           [  OK  ]

You can now put files in /tftpboot to download to your router. Change the folder if you wish. Beware of security issues. By default, anything in /tftpboot can be downloaded. You may wish to set the disable = yes when you aren’t planning on using TFTP, and restart xinetd again.