Nrpe Legacy mode during first installation


Hello, could you please tell me if NRPE Legacy Mode is something related the first installation or it’s something i can reach after have done the first setup ?

In the ini of these machines where i don’t know how they installed Nsclient i can read

; ALLOW INSECURE CHIPHERS and ENCRYPTION - Only enable this if you are using legacy check_nrpe client.insecure = true

allow arguments = true

allow nasty characters=true

payload length = 10240

I’m trying to run a check_nrpe command (launching an external script .bat) from Nagios server ver 2.x toward a client

In these clients there’s this version (, installed for dashboard’s purposes by our software supplier, so i cannot disinstall this version and i don’t know how they installed it, so i need to use their installation "as it is" On a test machine i disinstalled their version and i installed NSclient flagging Legacy mode and it works!

The command is :

SSL version $USER1$/check_nrpe -H $HOSTADDRESS$ -c check_lsw -t $ARG1$ -a $ARG2$

NO SSL version $USER1$/check_nrpe -H $HOSTADDRESS$ -c check_lsw -t $ARG1$ -n -a $ARG2$

What i know is that they use SSL , so i modified my command removing the “-n” parameter , but in this way i get the following error

2018-04-26 11:49:03: error:c:\source\nscp\include\socket/connection.hpp:137: Failed to read data: The I/O operation has been aborted because of either a thread exit or an application request

If i run the command without SSL i get, because they have SSL on

2018-04-26 11:24:02: error:c:\source\nscp\include\socket/connection.hpp:243: Failed to establish secure connection: unknown protocol: 252

I can add further informations, i’m a newbie of Nagios and i’m reading a lot.