Tech Blog

Had this frustrating issues with a Cisco Catalyst 9500 and enabling SNMP with AES 256.

Basically 256 AES encryption wont wor:

snmp-server user USER1 GROUP1 v3 auth sha PASSWORD1 priv aes 256 PASSWORD2

snmp-server group GROUP1 v3 priv

But these would:

snmp-server user USER1 GROUP1 v3 auth sha PASSWORD1 priv aes 128 PASSWORD2

snmp-server group GROUP1 v3 priv

To test I used following software:

Paessler SNMP Tester:

This is it working:

Paessler SNMP Tester 5.2.3 Computername: COMPUTER Interface: 192.168.1.2

07/08/2019 09:17:20 (2 ms) : Device: 192.168.1.1

07/08/2019 09:17:20 (3 ms) : SNMP V3

07/08/2019 09:17:20 (4 ms) : Uptime

07/08/2019 09:17:22 (2244 ms) : SNMP Datatype: ASN_TIMETICKS

07/08/2019 09:17:22 (2250 ms) : -------

07/08/2019 09:17:22 (2256 ms) : DISMAN-EVENT-MIB::sysUpTimeInstance = 300185783 ( 34 days )

07/08/2019 09:17:23 (2521 ms) : SNMP Datatype: SNMP_EXCEPTION_NOSUCHOBJECT

07/08/2019 09:17:23 (2523 ms) : HOST-RESOURCES-MIB::hrSystemUptime.0 = No such object (SNMP error # 222) ( 0 seconds )

07/08/2019 09:17:23 (2524 ms) : Done

This is it broken:

Paessler SNMP Tester 5.2.3 Computername: COMPUTER Interface: 192.168.1.2
06/08/2019 12:22:13 (2 ms) : Device: 192.168.1.1
06/08/2019 12:22:13 (3 ms) : SNMP V3
06/08/2019 12:22:13 (4 ms) : Uptime
06/08/2019 12:22:18 (4237 ms) : SNMP Datatype: ASN_PRIMITIVE
06/08/2019 12:22:18 (4242 ms) : -------
06/08/2019 12:22:18 (4245 ms) : DISMAN-EVENT-MIB::sysUpTimeInstance = No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003) ( 0 seconds )
06/08/2019 12:22:22 (8462 ms) : SNMP Datatype: ASN_PRIMITIVE
06/08/2019 12:22:22 (8466 ms) : HOST-RESOURCES-MIB::hrSystemUptime.0 = No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003) ( 0 seconds )
06/08/2019 12:22:22 (8468 ms) : Done