snmpwalk: Decryption error for APC Rack PDU

Question

I have an APC Rack PDU (AP7920) and have configured:

• [x] Enable SNMPv3 access
• Username: switch
• Authentication Passphrase: test
• Privacy Passphrase: test
• Authentication Protocol: (o) MD5
• Privacy Protocol: (o) DES
• Access Control: [x] Enable, Username: switch, NMS IP/Host Name: 0.0.0.0

Now when I execute snmpwalk I get:

# snmpwalk -v3 -a MD5 -A test -u switch -x DES -X test 192.168.1.1
snmpwalk: Decryption error

What am I doing wrong?

My goal is to switch outlets via SNMP

Answer 1

Unfortunately I can't comment yet, so giving here my 2 cents:

1. your snmpwalk command misses the option to specify the security level:

   -l LEVEL set security level (noAuthNoPriv|authNoPriv|authPriv)

since you specify both Authentication and Privacy, you might try again with:

# snmpwalk -v3 -a MD5 -A PqzRcPor1QPyBHRdVOjA -u switch -l authPriv -x DES -X PqzRcPor1QPyBHRdVOjA 192.168.1.1

2. have you tried switching MD5/DES to something else like SHA/AES and see if you get something different ?

The above answer by Lex Li is correct too: APC specifies a password length should be no less than 12 chars.

Answer 2

You cannot use "test" as passphrase as it is too short. The RFC document might not make that very clear, but various vendors have stated that.

Reference

https://docs.oracle.com/cd/E37444_01/html/E37449/gpqnr.html