Cisco IOS Cookbook, 2nd Edition

Using SNMP to Copy a New IOS Image

Problem

You want use SNMP to remotely upgrade a router’s IOS.

Solution

Before you can upload or download the router’s IOS image to a TFTP server, you have to set up a valid read-write SNMP community string:

Router#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#snmp-server community ORARW rw
Router(config)#end

Then you can download a copy of your router’s current IOS file to your TFTP server with the following Unix commands:

Freebsd% touch /tftpboot/c2600-jk9o3s-mz.122-7a.bin
Freebsd% chmod 666 /tftpboot/c2600-jk9o3s-mz.122-7a.bin
Freebsd% snmpset –v1 -c ORARW Router .1.3.6.1.4.1.9.2.10.9.172.25.1.1 s c2600-jk9o3s-mz.122-7a.bin
enterprises.9.2.10.9.172.25.1.1 = "c2600-jk9o3s-mz.122-7a.bin"
Freebsd%

Use the following commands to upload an IOS file from your TFTP server to the router’s flash memory:

Freebsd% chmod 666 /tftpboot/c2600-jk9o3s-mz.122-7a.bin
Freebsd% snmpset –v1 -c ORARW Router .1.3.6.1.4.1.9.2.10.6.0 i 1
enterprises.9.2.10.6.0 = 1
Freebsd% snmpset –v1 -c ORARW Router.1.3.6.1.4.1.9.2.10.12.172.25.1.1 s c2600-jk9o3s-mz.122-7a.bin
enterprises.9.2.10.12.172.25.1.1 = "c2600-jk9o3s-mz.122-7a.bin"
Freebsd%

Discussion

The first example demonstrates how to use SNMP to force a router to download its IOS file to a TFTP server. Most TFTP servers will not accept an incoming transfer unless the destination file is world writable. On Unix computers, the touch command creates a file, and the chmod command gives ...