Recipe 1.17 Extracting Hardware Inventory Information

1.17.1 Problem

You need an up-to-date list of the hardware configurations and IOS levels of all of your routers.

1.17.2 Solution

The Bourne shell script in Example 1-3 uses SNMP to extract useful version information from a list of routers. By default, the script stores this data in CSV format so that you can easily import it into a spreadsheet for analysis. No arguments are required or expected.

Example 1-3. inventory.sh

#!/bin/sh
#
#    inventory.sh -- a script to extract valuable information
#                    from a list of routers. (Name, Type, IOS version)       
#
#
# Set behaviour
public="ORARO"
workingdir="/home/cisco"
#
LOG=$workingdir/RESULT.csv
infile=$workingdir/RTR_LIST
snmp="/usr/local/bin/snmpget -v1 -c $public"
#
while read device
do
  $snmp $device sysName.0 > /dev/null
  if [ "$?" = "0" ] ; then
    rtr=`$snmp $device .1.3.6.1.4.1.9.2.1.3.0 | cut -f2 -d\" `
    type2=`$snmp $device .1.3.6.1.4.1.9.9.25.1.1.1.2.3 | cut -f2 -d$ `
    ios=`$snmp $device .1.3.6.1.4.1.9.9.25.1.1.1.2.5 | cut -f2 -d$ `
    prot=`$snmp $device .1.3.6.1.4.1.9.9.25.1.1.1.2.4 | cut -f2 -d$ `
    echo "$device, $rtr, $type2, $ios, $prot" >> $LOG                 
  fi
done < $infile

1.17.3 Discussion

The inventory.sh script extracts hardware and IOS version information directly from the routers using SNMP. This ensures that the data is up-to-date. You can even automate this script to run periodically, ensuring that your inventory information is always accurate. In a large network, this is much easier than keeping track of this information manually.

By default, the script captures the device name, router type, IOS version, and IOS feature set from each router. It stores this gathered information in a CSV format file called RESULT.csv.

This script requires NET-SNMP to gather the information via SNMP. You can use a different SNMP package if you prefer, but then you will need to modify the syntax appropriately. The script expects to find the executable snmpget in the /usr/local/bin directory. Again, if you keep this file in a different location, you will need to define the correct location in the snmp variable. For more information on NET-SNMP, see Chapter 17 or Appendix A.

Before running this script in your network, you will need to modify two variables. The first is the public variable. This value must contain your read-only SNMP community string. The script assumes that you have the same community string on all of the routers in the list. The second variable that you will need to set is workingdir, which must contain the name of the directory that you wish to run the script from.

Finally, you will need to build a file called RTR_LIST that contains the names of all of your routers, with one name on each line. The script expects to find this file in the working directory.

The output of the script is a CSV file, which you can import into a spreadsheet to analyze and sort the results as required. Table 1-4 shows an example of the script's output as it might look in a spreadsheet.

Table 1-4. Output results from the inventory.sh script

Router	Router Name	Type	IOS version	IOS feature set
Toronto	toronto	C2600	12.2(13)	IP|FIREWALL 2 PLUS 3DES
Boston	boston	C3620	12.2(13)	IP|3DES PLUS
Newyork	newyork	C3620	12.2(13)	IP|3DES PLUS
Tampa	tampa	C2500	12.0(25)	IP PLUS
Sanfran	sanfran	C7200	12.0(12a)	IP|IPX|VLAN

1.17.4 See Also

Chapter 17; Appendix A