> ## Content Index > Fetch the complete content index at: https://www.simplykyra.com/llms.txt > Use this file to discover other available public pages before exploring further. # How I Solved My SSH Connection Error: No Matching Host Key Type Found - URL: https://www.simplykyra.com/blog/how-i-solved-my-ssh-connection-error-no-matching-host-key-type-found/ - Published: 2022-09-28T13:30:00.000Z - Updated: 2023-05-10T15:55:59.000Z - Description: After a computer update I could no longer connect to my reMarkable via SSH as I had an error saying: "unable to negotiate with host: no matching host key type found". This is how I fixed the issue. - Author: Kyra - Tags: reMarkable, Config, iTerm, MacOS, SSH, Terminal, #wordpress, #simplykyra_em3y2f, Technology, #Import 2023-03-26 03:43 In the last month or so I stopped being able to `SSH` into my reMarkable as I normally do. After putting off fixing it for a bit I finally decided to just sit down and figure out what was wrong. I got it working and had to share how I know connect to my device in case the same thing happens to you. ![Pinterest-geared image showing the post's title, main URL, and four images also shown below. ](https://storage.ghost.io/c/d3/68/d3684a67-f3a9-4c11-9d37-bc9fc8fe73ed/content/images/wordpress/2022/09/compressed_How-I-Solved-My-SSH-Connection-Error-No-Matching-Host-Key-Type-Found-Pinterest.jpg?resize=471%2C707&ssl=1) --- *Below I replaced my host IP address with XXX.XXX.X.XXX so instead of typing in XXX.XXX.X.XXX please enter whatever IP address you’re trying to connect to instead.* --- ## *Edits* ### October 7th, 2022: *I just updated my reMarkable to version 2.15.0.1067\. Had issues connecting. Error: `Connection closed by ... port 22`. Fixed this by going into my `~/.ssh/known_hosts` file and removing the corresponding line.* *With the update the reMarkable now accepts different host key algorithms so this below fix is no longer needed. Keeping the post around in case someone else has a similar issue.* ### March 22nd, 2023: When moving my website over I lost my previous comments so I wanted to include [Jen Lampton's](https://www.jenlampton.com/?ref=simplykyra.com) comment where I was asked if I had ever found a solution that allowed me to connect using my SSH key again. I wasn't able to answer but she later replied: > I just discovered a solution for the public key – I’ll post here in case anyone else finds your helpful article 🙂 > \`PubkeyAcceptedAlgorithms +ssh-rsa\` And now on to the previously written post. --- ## *How I Connected Before* Before going into how I now connect to my reMarkable I wanted to first mention my earlier post that showed [how I access my reMarkable through the command line](https://www.simplykyra.com/2021/02/03/learn-how-to-access-your-remarkable-through-the-command-line/). In addition to the simple `SSH` command it also mentions how I used my public key to skip entering my password (using the `.ssh/authorized_keys` file) *AND* how I created a shortcut (using `.ssh/config`) so I could skip entering my username and IP address each time. In case you already know how to use `SSH` but can’t find the information you need to connect to your reMarkable you can find it on your device here: ![Image is a photo of my reMarkable showing the GPLv3 Compliance along with my username and blanked out password and IP addresses. ](https://storage.ghost.io/c/d3/68/d3684a67-f3a9-4c11-9d37-bc9fc8fe73ed/content/images/wordpress/2021/01/compressed_IMG_9904.jpg?resize=750%2C563&ssl=1) *The information you need to connect to your reMarkable can be found under Settings > Help > Copyrights and licenses > General Information. Here you’ll see the GPLv3 Compliance which shows your username, password, and the IP addresses.* --- ## *The Problem* After I upgraded my operating system to the macOS Ventura (13.0 beta) I was was no longer able to `SSH` into my reMarkable device. Specifically: ``` ❯ ssh root@XXX.XXX.X.XXX Unable to negotiate with XXX.XXX.X.XXX port 22: no matching host key type found. Their offer: ssh-rsa ``` `SSH` (Secure Shell) is a secure method to connect and communicate between two devices. The security comes from the public key cryptography it uses to verify that who you’re talking to is actually who you think it is. One type of algorithm it can use is `RSA`. Back in 2021 `OpenSSH` released version 8.8 where it deprecated the [ssh-rsa signature scheme as it used the SHA-1 hash algorithm in conjunction with the RSA public key algorithm (link to Icarus.sg)](https://ikarus.sg/rsa-is-not-dead/?ref=simplykyra.com). This change shouldn’t be an issue as most systems use the modern version of `OpenSSH` which will see the `RSA` key and switch to a stronger signature scheme. So it shouldn’t be an issue. My problem was that my computer was using the updated `OpenSSH` so it disables `RSA` by default (doesn’t accept `ssh-rsa` signature schemes) while the way reMarkable is configured will *only* use `RSA`… hence the discrepancy. --- ## *The Solution* ### *Using SSH Command* To get around the current error you’ll need to alter that command a bit to specify what the host key algorithm you want to use is by passing in the option command `-o` and following it with `HostKeyAlgorithms` and the specific algorithm you want which in this case is `ssh-rsa`. Here I just want to add `ssh-rsa` to the list of preferred host key signature algorithms so I used a `+` to specify that. If I wanted to remove it from the list I’d use a `-` while a `^` moves it to the head of the default list. You can learn more about this by typing in `man ssh_config` in your terminal and navigating down to `HostKeyAlgorithms`. My `SSH` statement thus went from `ssh root@XXX.XXX.X.XXX` to `ssh -oHostKeyAlgorithms=+ssh-rsa root@XXX.XXX.X.XXX` and now, after asking my password, I’m able to connect to my reMarkable! ```bash ❯ ssh -oHostKeyAlgorithms=+ssh-rsa root@XXX.XXX.X.XXX root@XXX.XXX.X.XXX's password: ｒｅＭａｒｋａｂｌｅ ╺━┓┏━╸┏━┓┏━┓ ┏━┓╻ ╻┏━╸┏━┓┏━┓ ┏━┛┣╸ ┣┳┛┃ ┃ ┗━┓┃ ┃┃╺┓┣━┫┣┳┛ ┗━╸┗━╸╹┗╸┗━┛ ┗━┛┗━┛┗━┛╹ ╹╹┗╸ reMarkable: ~/ ``` ![Image shows the same text as above but in a screenshot of the terminal using color. ](https://storage.ghost.io/c/d3/68/d3684a67-f3a9-4c11-9d37-bc9fc8fe73ed/content/images/wordpress/2022/09/compressed_2022-09-15-at-7.32.46-AM.png?resize=750%2C366&ssl=1) Figured I’d share a picture of what this looks like with color. --- ### *Using a Shortcut* If you don’t want to specify the key algorithm every time (or even the username and host) you can create a shortcut. To create the shortcut you’ll need to navigate to the `~/.ssh` directory and edit, or create, a `config` file. Here’s what my updated config file looks like now with the `HostKeyAlgorithms` specified (before it just had the first three lines): ```config Host remarkable HostName XXX.XXX.X.XXX User root HostKeyAlgorithms=+ssh-rsa PubkeyAcceptedKeyTypes=+ssh-rsa ``` Here I call my connection `remarkable` so I just need to type `ssh remarkable` into the terminal when I want to connect. You can call yours whatever you want by changing the `remarkable` word at the beginning after `Host`. If you want to learn more about how I did this, without the `ssh-rsa` additions, I talked about it in my [Learn How to Access Your reMarkable Through the Command Line](https://www.simplykyra.com/2021/02/03/learn-how-to-access-your-remarkable-through-the-command-line/) post under the heading: *Forget the Username and IP Address by Creating a Shortcut*. --- ## *Addendum: What Version of SSH Your Device Is Running* While working my way through this issue I found some other commands I could run to better understand the `SSH` my device(s) were running. In case you might also be interested in this I figured I’d include it here. *First a quick aside: I ran these commands on September 15th, 2022 while running `Version 2.14.3.977` on my reMarkable (Dropbear v2019.78) and the beta macOS 13.0 Ventura on my computer (OpenSSH\_9.0p1, LibreSSL 3.3.6*)*.* To find the exact version of `SSH` your device is running you can run `ssh` with the version flag `-`V. This means you can run it on your computer or on any device you have `ssh` access to. For me, after fixing my `ssh` issue and shown below, I ran it on my computer and saw my Mac is using `OpenSSH_9.0p1` and `LibreSSL 3.3.6`. I then connected to my reMarkable and ran it again to see that my reMarkable is instead running `Dropbear v2019.78`. ![Image shows the `ssh -V` command on both my computer and reMarkable. Both output different ssh versions which makes sense as they conflict with `ssh-rsa`.](https://storage.ghost.io/c/d3/68/d3684a67-f3a9-4c11-9d37-bc9fc8fe73ed/content/images/wordpress/2022/09/compressed_2022-09-15-at-8.08.32-AM.png?resize=750%2C591&ssl=1) Even if you can’t connect to a device you can still find out what version of `SSH` it’s running through the verbose mode `-`v command when attempting to connect; in this case a lowercase `v` rather than the capitalized version above. Verbose mode explains what’s happening when it attempts to connect and outputs the `SSH` version of your device before it realizes whether it can connect or not. I also tried doing this when my reMarkable was turned off but, as it was turned off, the operation timed out as it couldn’t connect and thus couldn’t output its `SSH` version. ``` ❯ ssh -v remarkable OpenSSH_9.0p1, LibreSSL 3.3.6 // My computer version ... debug1: Remote protocol version 2.0, remote software version dropbear_2019.78 debug1: compat_banner: no match: dropbear_2019.78 // My reMarkable version ... ``` ![Image shows the same text as before... just more colorful.](https://storage.ghost.io/c/d3/68/d3684a67-f3a9-4c11-9d37-bc9fc8fe73ed/content/images/wordpress/2022/09/compressed_2022-09-15-at-8.16.00-AM.png?resize=750%2C256&ssl=1) If you travel down the output you’ll eventually come across what `SSH` version your devices are using. --- Whether you’re having difficulty connecting to your reMarkable or some other device I hope this post has helped you. If so I’d love to hear how and what in the comments below! If my post was missing some crucial information feel free to share in the comments below and maybe it will help someone else later on. Have a great day! --- If you’re interested in getting any of my future blog updates I currently come out with a new one every second Wednesday and share them to my [Facebook page](https://www.facebook.com/SimplyKyra/) and [Instagram account](https://www.instagram.com/simplyartsykyra/?ref=simplykyra.com). You’re also more than welcome to join my email list located right under the search bar or underneath this post.