4.0.3 does not accept v3 Packets

NagiosEnterprises / nrpe

NRPE Agent

GNU General Public License v2.0

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4.0.3 does not accept v3 Packets #260

Closed Nudin closed 2 years ago

Nudin commented 2 years ago

As I understood the documentation, nrpe v4.0.3 should support v3 packages (as well as v4 and v2). But I use check_nrpe 3.2.1 to query a host with nrpe 4.0.3, and I get does not support Version 3 Packets; accepted a Version 2 Packet.

Nudin commented 2 years ago

Just found the following in the log of nrpe:

Error: (use_ssl == true): Request packet version was invalid!

sawolf commented 2 years ago

Hi @Nudin, thanks for reaching out. The reason NRPE has a protocol version 4 is because version 3 had some issues that may make it insecure (improper length/CRC calculation). Because of this, a v4 daemon won't ever accept a v3 packet. I didn't add an option to allow them since check_nrpe v3 will resend a v2 packet (which doesn't have security issues) if the v3 packet is rejected.