check_nrpe v3 Packets

[andyb4u]

Hi,

I have a question regards NRPE and version packets.

We are seeing these messages in /var/log/messages:

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check_nrpe: Remote x.x.x.x does not support Version 3 Packets

The check_nrpe plugin carrying out these checks is:

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NRPE Plugin for Nagios
Version: 3.2.1

The remote servers mentioned in the logs are all Linux servers with NRPE.

I understand from reading https://support.nagios.com/kb/article/n ... s-786.html
that this is expected behaviour for those servers running NRPE version less than 3. In these cases we should be able to stop these messages by either specifying the -2 when using the check_nrpe command or by upgrading NRPE on those server.

However we are also seeing this message logged for Linux servers which are running NRPE version 4.

I'm not sure why this is happening. Is this expected behaviour?

[benjaminsmith]

Hi,

However, we are also seeing this message logged for Linux servers which are running NRPE version 4

The older plugin, XI server-side, should be backward compatible with the newer NRPE agent running on the remote hosts. I just tested this using an old version for XI running checks against an agent using NRPE 4, and it's working without the message.

Can you double-check which version of NREP those hosts are running?

Also, the latest version,4, of NRPE has had a change to the packets as well. More details in the changelog.
https://github.com/NagiosEnterprises/nr ... ANGELOG.md

Best Regards,
Benjamin

[andyb4u]

I checked and they are running NRPE 4.02

[benjaminsmith]

Hi,

I checked and they are running NRPE 4.02

Can you let me know the exact name of the checks returning the messages, and send over the system profile, and I will try to test this out here.

Thanks, Benjamin

To send us your system profile.
Login to the Nagios XI GUI using a web browser.
Click the "Admin" > "System Profile" Menu
Click the "Download Profile" button

[andyb4u]

Hi,

I've PM'd you the profile and info requested.

Regards,
Andy

[ssax]

You will need to add the -2 for those Linux ones as well to stop it from logging that message.

[andyb4u]

I don't understand why we would need to do this.

We don't see this message for hosts using NRPE version 3.

My understanding is that a NRPE v3 client attempts to connect using a v3 packet by default. I assumed that a host running NRPE v4 would be able to handle this v3 packet.

[ssax]

The checks will still work without it but in order to get rid of that logged message you need to add -2:

https://support.nagios.com/kb/article/n ... s-786.html

It's because of the way the devs wrote the functionality, you can see here it checks for v2 first:

https://github.com/NagiosEnterprises/nr ... pe.c#L2115

While I agree that you logically shouldn't have to pass it you still need to in order to get rid of the message in the logs.

On the Linux system, are you seeing this?

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Request packet version was invalid

Or this?

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does not support version 3/4 packets

Or this?

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does not support Version 3 Packets

[andyb4u]

We are seeing:

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Request packet version was invalid

[ssax]

That's what I get as well, you'll need to pass the -2 to get rid of it from the XI server and the remote server logs. The checks still work but that message is logged on both without it.