SNMP Question

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Hello ITPro.TV... Was wondering if you could help me wrap my head around this practice exam question I ran across while using the transcender test provided with the service. I've done some research on the differences between auth/noauth/& priv, but this question seems to contradict itself.

*Which of the following commands configures an SNMP host to authenticate a user by username and send clear text notifications, the receipt of which will be acknowledged by the receiver?

A. Router(config)# snmp-server host 192.168.5.5 informs version 3 noauth public
B. Router(config)# snmp-server host 192.168.5.5 traps version 3 auth public
C. Router(config)# snmp-server host 192.168.5.5 informs version 2c public
D. Router(config)# snmp-server host 192.168.5.5 informs version 3 authpriv public*

So this wasn't really covered in the course. The three commands that were covered in the course were as follows:
snmp-server view CustomViewName 1.3.6.1.4.1.9.9.25.1.1.1.2.7 included <-- Create view
snmp-server group CustomGroupName v3 auth read CustomViewName <--Create group and associate with view
snmp-server user CustomUserName CustomGroupName v3 auth md5 cisco123 <--Create user and associate with group

I'm not really sure what the command "snmp-server host x.x.x.x" even does, but I do know that you have to use the word "informs" in order to adhere to the requirement "the reciept of which will be acknowledged by the receiver". So B is out right away. Then I start to focus on the only real difference which is noauth, 2c, or authpriv..

Well, I see also in the question that it is a requirement to authenticate by user, so version 2c is out. Now we are left considering only option A and option D. or noauth vs authpriv.

My understanding of noauth is that it doesn't require authentication or privacy (encryption), so that can't be it... My understanding of authpriv is that it requires not only authentication, but also privacy. So option D can't be correct because no clear text notifications would be sent if the entire exchange is encrypted....

Where did I go wrong in my logic here? What is the snmp-server host x.x.x.x command for compared to what was covered in the class?

Thanks!

Regards,
Adam Tyler

@Adam-Tyler said in SNMP Question:

Hello ITPro.TV... Was wondering if you could help me wrap my head around this practice exam question I ran across while using the transcender test provided with the service. I've done some research on the differences between auth/noauth/& priv, but this question seems to contradict itself.

Which of the following commands configures an SNMP host to authenticate a user by username and send clear text notifications, the receipt of which will be acknowledged by the receiver?
A. Router(config)# snmp-server host 192.168.5.5 informs version 3 noauth public
B. Router(config)# snmp-server host 192.168.5.5 traps version 3 auth public
C. Router(config)# snmp-server host 192.168.5.5 informs version 2c public
D. Router(config)# snmp-server host 192.168.5.5 informs version 3 authpriv public

I'm not really sure what the command "snmp-server host x.x.x.x" even does,

You're directing the SNMP messages to a recipient.

A. Router(config)# snmp-server host 192.168.5.5 informs version 3 noauth public

I believe is the answer to the question's component parts:
authenticate a user by username : snmp v3 noauth (authenticates by username)

send clear text notifications : snmp v3 noauth (does not encrypt)

the receipt of which will be acknowledged by the receiver - informs does this for us.

Where did I go wrong in my logic here?

You have to choose the best answer in this instance that meets all the requirement of the question at hand. The answer D almost met the requirement but doe encrypt and doesn't send clear text notifications.

What is the snmp-server host x.x.x.x command for compared to what was covered in the class?

I'm not sure I remember exactly what show this was covered in, please let me know and maybe I can take a look at it and try and answer.

Thanks!

Regards,
Adam Tyler

Thanks Ronnie, you seem to be the Cisco authority there at ITPro.. They make you respond to all the forum posts? You do a great job, just wondering.

I'm prepping for my CCNA exam (ICND2) and my question stems from watching the 200-105 SNMP show.. Your explanation sounds great except for the part where you say "authenticate a user by username: snmp v3 noauth".. The Cisco documentation I am reading states that noauth is equal to the "noAuthNoPriv" security level which has the following description:

"Communications without authentication and privacy."

That doesn't sound like it supports authentication by username... It would have to be "auth" would it not?

Oh, Ps.. This particular command was not covered in the SNMP show for CCNA (ICND2), it just appears on the transcender exam.

Regards,
Adam Tyler

Wait a second.. I just found another description of "noauth/noAuthNoPriv" that says this:

"Username match"

So does this make V3 work more like V2c? In that as long as the username matches it works? Authentication and communications are send in clear text and the username sort of acts like a community string as it does in v2?

Regards,
Adam Tyler

@Adam-Tyler,

I believe it does...I think in reality "noAuth" may be shorthand for "noAuthNoPriv"

It is confusing as heck... My notes show there is a difference from the definitions and the commands that are actually entered into the CLI.

These are the CLI commands as far as I can tell:
auth / priv / noauth

However, these are the definitions in the same order:
authNoPriv / authPriv / noAuthNoPriv

Dang it Cisco.....

Regards,
Adam Tyler

I am noticing conflicting explanations in the Transcender 200-105 practice test:

In question Ref: Cert-200-105.5.1.1, the explanation states: "the keyword noauth in the configuration indicates that no authentication and no encryption are provided"

In the next question Ref: Cert-200-105.5.1.4, the explanation states: " the noauth keyword specifies authentication by username only and no encryption."

@lee-seeman,

My apologies for the late reply. I cannot explain the distinction that the transcender team chose except to say maybe two different people on their team were writing the explanations. But you can definitely contact their support through transcender.com and ask them. They're a great team and will hopefully give you a reply!