Is there a way to know if a device has version 3 of SNMP enabled without the credentials?

Question

I need to do a device discovery which is working fine for version 1,2 because the community name by default "public" help me on this, but for the version 3 the credentials are required, do ou know any tool o method to know that ?

Answer 1

As described in https://www.rfc-editor.org/rfc/rfc3414#section-4 you can send an empty v3 pdu. If the device supports v3 protocol it will respond (a report message) with it's snmpEngineID.

'This may be accomplished by generating a Request message with a securityLevel of noAuthNoPriv, a msgUserName of zero-length, a msgAuthoritativeEngineID value of zero length, and the varBindList left empty.'

Answer 2

@DominikPawlak already shows the RFC compliant approach. If you want some code sample, #SNMP has a sample called snmpdiscover,

http://sharpsnmplib.codeplex.com/wikipage?title=SNMP%20Device%20Discovery&referringTitle=Documentation