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MacOS Sierra: Unable to negotiate with IP X.X.X.X port 22 no matching host key type found. Their offer: ssh-dss

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

Issue

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

techkaki-MacBook-Pro:~ techkaki$ ssh root@10.10.10.243
Unable to negotiate with 10.10.10.243 port 22: no matching host key type found. Their offer: ssh-dss

Root Cause

OpenSSH Version 7 and above disable DSA key by default.

Solution

A) To enable the ssh-dss (DSA) key exchange algorithm  using the HostKeyAlgorithms option:

ssh -o HostKexAlgorithms=+ssh-dss  aimsadm@10.10.10.82

B) Enable ssh-dss (DSA) on ssh_config by adding HostkeyAlgorithms +ssh-dss at the end of the ssh_config file.

sudo nano /etc/ssh/ssh_config

Screen Shot 2017-05-22 at 11.54.31 AM

Hope this information will help 🙂

Reference link:-

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

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

Mac OS X – taking screenshot and save it to clipboard

October 14, 2015 by @HKw@! | No Comments | Filed in Mac OS X

To capture a screenshot in Mac OS X, it is very easy to do it. I already shared the tutorial on how to capture screenshot in Mac OS X, you may click HERE to view my previous tutorial.

In Mac OS X, captured screen shot will be automatically saved as a PNG file on your desktop with the filename starting  followed by a number. But, do you know that you can just paste the screenshot directly to program like PowerPoint or word instead of save it on Desktop?

To do it, just refer the following shortcut key:- (more…)