SNMP exercises 
AfNOG 11, Kigali 

Please run all exercises on your assigned router: 
Row 1: 196.200.218.249 
Row 2: 196.200.218.250 
Row 3: 196.200.218.251 
Row 4: 196.200.218.252 
Row 5: 196.200.218.253 

1. Make sure that snmp commands work 
   * snmpstatus -v1 -c afnog 196.200.218.254 
   * What do you see? 
   * Does v2c, v3 also work? Why, why not? 
   * Does it also work to your local machine? Why, why not? 
1. Do an SNMP GET request 
   * snmpget -v2c -c afnog 196.200.218.254 sysUpTime.0 
   * Why do you need the .0? 
   * easier: snmpwalk -v2c -c afnog 196.200.218.254 sysUpTime 
2. Browse a MIB file 
   * MIBs are installed under: /usr/share/snmp/mibs 
   * Look at /usr/share/snmp/mibs/RFC1213-MIB.txt 
   * Try to read the hierarchy and find the OID for sysUpTime Hint: mib-2 is .1.3.6.1.2.1 
   * Verify: snmpwalk -v2c -c afnog 196.200.218.254 «yourOID» 
   * If you want to get the results without name resolution do
snmpwalk -v2c -On -c afnog 196.200.218.1 «yourOID»
or if you want the full name hierarchy use -Of 
   * Find some information 
      * What is the location of the router in your workgroup (196.200.218.249/250/251/252/253 for row 1/2/3/4/5)? Hint: Check in the system tree 
      * What is the MAC address of FastEthernet0/1 on this router? Hint: Get the whole interface table and try to read it - it’s a table by ifIndex - find the ifIndex for FastEthernet0/1 and find the MAC address for this interface 
      * What’s the IP address for this interface? Get ipAdEntIfIndex from the ip tree 
   * Add a custom MIB 
      * Run the following command:
snmpwalk -Of -v2c -c afnog 196.200.218.254 .1.3.6.1.4.1.9.9.13.1.3 
      * What do you notice? 
      * To insert Cisco-specific MIB information, you need to download a MIB file and put it in your path. scp them from the NOC server
As root:
cd /usr/share/snmp/mibs
wget http://noc/files/CISCO-SMI.my
wget http://noc/files/CISCO-ENVMON-MIB.my 
      * Add variables so it can find the mibs 
export MIBDIRS=/usr/share/snmp/mibs 
export MIBS=ALL 
      * Try the snmpwalk command again - what is different now? 
            * Note: You can find MIBs on the vendor website or FTP server usually, e.g. Cisco MIBs are in ftp://ftp.cisco.com/pub/mibs/v2/ - to see what information you can get via SNMP in addition to the standard you can read through the MIB files or vendor doc