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macOS Sierra – Error on SSH “no matching key exchange method found. Their offer: diffie-hellman-group1-sha1”

May 22, 2017 by @HKw@! | No Comments | Filed in centos, Linux, Mac OS X, Open Source

Issue

My latest MacOS X 10.12 release failed to ssh to network devices with the following error:

techkaki-MacBook-Pro:~ techkaki$ ssh aimsadm@10.10.178.243
Unable to negotiate with 10.10.178.243 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

Root Cause

For error message above show that the client and server were unable to agree on the key exchange algorithm.

As per checking on my Mac OS X, i noticed that my Mac OS X running on OpenSSH version 7.

techkaki-MacBook-Pro:~ techkaki$ ssh -V
OpenSSH_7.4p1, LibreSSL 2.5.0

According to openssh website, some of the older algorithms are not enabled by default on OpenSSH Version 7 and above.

Solution

A) To enable the diffie-hellman-group1-sha1 key exchange algorithm  using the KexAlgorithms option:

ssh -o KexAlgorithms=+diffie-hellman-group1-sha1 aimsadm@10.10.143.82

B) Enable SHA1 on ssh_config by adding KexAlgorithms +diffie-hellman-group1-sha1 at the end of the ssh_config file.

sudo nano /etc/ssh/ssh_config

Screen Shot 2017-05-22 at 11.26.05 AM

Hope this information will help 🙂

Reference link:-

https://www.openssh.com/legacy.html

NagiosXI – SQL: SQL Error [ndoutils]

October 21, 2015 by @HKw@! | No Comments | Filed in centos, Linux, Nagios, Open Source

Problem Symptoms

Error “SQL: SQL Error [ndoutilsSQL: SQL Error [ndoutils]

SQL-SQL Error

If you see above error when you logon the NagiosXi Server,  it may be a symptom of one or more crashed tables. The steps outlined below allow you to repair the MySQL database tables used by Nagios XI.

Repairing MySQL Tables

  • First, login to your Nagios XI server as the root user via SSH.
  • Run the Nagios XI database repair script with the following command:

cd /usr/local/nagiosxi/scripts
./repair_databases.sh

This process may take several minutes to complete, depending on the size of your database

If above step unable to solve the problem, you may have to contact Nagios support team

Could not construct return packet in NRPE handler check client side (nsclient.log) logs…

October 16, 2015 by @HKw@! | 2 Comments | Filed in Nagios, Open Source

When i try to run check _nrpe command from Nagios to perform a memory check the physical memory of the Windows Server 2012, i get the following error message:-

NRPE error

From the above error message it show that Nagios Server unable to get the results from the NSClient services. It is because NRPE module is not enable in the NSClient services. By default, NRPE module is not enable.

To enable the NRPE module, below are the steps:

1. navigate to the NSClient++ directory which should be in your C:\Program Files directory.

2. There is a file named NSC.ini in there. This is the main configuration file for NSClient. Open this in your favorite text editor.

3. Now in the [NRPE] section we need to enable the following:

port 5666

allow_arguments=1

 

4. Once done, save the NSC.ini files and restart NSClient++ services

5. Now you try the run the same command again and it should return the expected result.

checkMEM