The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘ssh/sshd’ Category

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ESXi: rsync over ssh between two ESXi machines (and overcoming a potential “sh: rsync: not found”)

Posted by jpluimers on 2026/10/20

I have been using rsync for years now to sync directories around on VMware ESXi systems with great success.

Usually when upgrading to new physical machines, I synced the things to migrate to a big disk, then physically mounted that disk in a new machine.

Not this time: because of an unscheduled event I had to bring up the target machine in a different place before I could assemble the data on the big disk.

But since there was a network tunnel between the networks of both ESXi machines, I wanted to transfer over ssh: a thing I had done numerous times between various Linux and unix machines.

The cool thing is that rsync supports remote connections over ssh out of the box. Between ESXi machines, I bumped into this error though:

sh: rsync: not found
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: error in rsync protocol data stream (code 12) at io.c(226) [Receiver=3.1.2]
Command exited with non-zero status 12

The last three lines are collateral of the first line, which I queried [Wayback/Archive] “sh: rsync: not found” – Google Search. Further below I will go deeper into the rabbit-hole I took, but the actual solution was to Read the rest of this entry »

Posted in *nix, *nix-tools, ash/dash, ash/dash development, BusyBox, Development, ESXi6, ESXi6.5, ESXi6.7, man/manual pages, OpenSSH, Power User, rsync, Scripting, Software Development, SSH, ssh/sshd, Virtualization, VMware, VMware ESXi | Leave a Comment »

Jan-Piet Mens :: Deploying SSH host keys and certificates with Ansible

Posted by jpluimers on 2026/09/17

For my future self: [Wayback/Archive] Jan-Piet Mens :: Deploying SSH host keys and certificates with Ansible

--jeroen

Posted in *nix, *nix-tools, Development, DevOps, Infrastructure, Power User, Scripting, Software Development, ssh/sshd, YAML | Leave a Comment »

Tribal Knowledge? Getting the public keys from github and gitlab users from their username

Posted by jpluimers on 2025/04/03

Learned a while ago: if you have the username from a GitHub or GitLab user, you can download interesting that sometimes can make life easier (but not necessarily more secure):

  • github.com/username.keys gives you their public SSH keys
  • gitlab.com/username.keys gives you their public SSH keys
  • github.com/username.png gives you their profile image

And that there are tools like gh, glab and age that can make direct use of them.

I love Twitter, so thanks for these for teaching me these little tricks:

Read the rest of this entry »

Posted in *nix, *nix-tools, ArchiveTeamWarrior, Conference Topics, Conferences, Development, Event, GitHub, GitLab, Internet, InternetArchive, OpenSSH, Power User, Software Development, Source Code Management, SSH, ssh/sshd, WayBack machine | Tagged: , | Leave a Comment »

Quit Nested SSH Sessions: use one more ~ for each nesting

Posted by jpluimers on 2024/11/18

Never too old to learn:

  • [Wayback/Archive.is] Quit Nested SSH Sessions

    works with ssh as well but is much simpler: press as many ~ as level of nest before . (by default, ~ is the escape character while . is to terminate ssh).

  • [Wayback/Archive.is] How can I break out of ssh when it locks? – Ask Ubuntu

    Notice that because hitting ~~ causes ssh to send the ~ instead of intercepting it, you can address N nested ssh connections by hitting ~ N times. (This only applies to ~s that directly follow an Enter.) That is to say that Enter~~~~~. terminates an ssh session 5 layers deep and keeps the other 4 intact.

So this is basically an extension of my 2017 blog post OpenSSH Escape Sequences (aka Kill Dead SSH Sessions) – The Lone Sysadmin (:

–jeroen

Posted in *nix, *nix-tools, Power User, ssh/sshd | Leave a Comment »

Tailscale SSH · Tailscale

Posted by jpluimers on 2024/07/12

Reminder to self to play around with [Wayback/Archive] Tailscale SSH · Tailscale

Tailscale SSH allows Tailscale to manage the authentication and authorization of SSH connections on your tailnet.

Read the rest of this entry »

Posted in *nix, *nix-tools, Hardware, Network-and-equipment, Power User, ssh/sshd, Tailscale, VPN, Wireguard | Leave a Comment »

Installing Windows OpenSSH from the command-line on Windows 10 and 11

Posted by jpluimers on 2023/03/28

While writing On my reading list: Windows Console and PTY, I found out that OpenSSH had become available as an optional Windows feature.

It was in [Wayback/Archive.is] Windows Command-Line: Introducing the Windows Pseudo Console (ConPTY) | Windows Command Line:

Thankfully, OpenSSH was recently ported to Windows and added as a Windows 10 optional feature. PowerShell Core has also adopted ssh as one of its supported PowerShell Core Remoting protocols.

Here are a few links:

Read the rest of this entry »

Posted in *nix, *nix-tools, Communications Development, ConPTY, Console (command prompt window), Development, Internet protocol suite, OpenSSH, Power User, SSH, ssh/sshd, TCP, Windows, Windows 10, Windows 11 | Leave a Comment »

Since about 5 months now, there has been a new Chocolatey package maintainer for OpenVPN

Posted by jpluimers on 2022/08/26

Last winter, I discovered that the OpenVPN version on Chocolatey was really old: it had not been updated since 2019.

Most  Chocolatey maintainers are volunteers and sometimes the burden can become too large. Back then the maintainer was [Wayback/Archive] Chocolatey Software | wget, but luckily [Wayback/Archive] Chocolatey Software | dgalbraith has stepped in and in March 2022 bumped the version from [Wayback/Archive] Chocolatey Software | OpenVPN 2.4.7 to [Wayback/Archive] Chocolatey Software | OpenVPN – Open Source SSL VPN Solution 2.5.4 and kept maintaining (currently there is [Wayback/Archive] Chocolatey Software | OpenVPN – Open Source SSL VPN Solution 2.5.7).

Read the rest of this entry »

Posted in *nix, *nix-tools, Chocolatey, Hardware, Network-and-equipment, OpenVPN, Power User, ssh/sshd, VPN, Windows | Leave a Comment »

Cryptosense Discovery

Posted by jpluimers on 2022/03/15

This is cool: [Wayback] Cryptosense Discovery:

Free tool that discovers security configuration errors in SSH and TLS servers and explains how to fix them. Supports STARTTLS and can also scan HTTPS, POP3, IMAP and SMTP servers.

It gives you a list of servers a target domain uses (for purposes like web, email, etc) that can have external encryption enabled, then allows you to test these.

The list by default has only servers within that target domain enabled, but you can optionally include other servers (for instance if a domain uses a third party for their SMTP handling).

Basically it is the web-counterpart of a tool like testssl.sh (which I have written about before).

Found while checking out how to test the MX security of a domain using [Wayback] testssl.sh as I forgot the syntax, which in retrospect is dead easy as per [Wayback] tls – How to use testssl.sh on an SMTP server? – Information Security Stack Exchange (thanks [Wayback] Z.T.!):

…

testssl.sh --mx <domain name>

works fine.

testssl.sh -t smtp <ip>:25

and

testssl.sh -t smtp <ip>:587

also work fine.

Note that not specifying the port assumes port 443, despite specifying protocol smtp. That doesn’t work.

…

Also, you might try discovery.cryptosense.com which does the same thing only better

That website is made by the cool people at [Wayback] Cryptosense.

Both are a lot easier than the alternatives described in [Wayback] Blog · How to test SMTP servers using the command-line · Halon MTA: using nslookup and dig for determining the affected hosts, using nc or telnet for testing basic connectivity, using [Wayback/Archive.is] openssl s_client to test TLS, and [Wayback/Archive.is] smtpping for measuring throughput.

In addition to the above tools mentioned in the blog, I’ve also used sendEmail (note case sensitivity), ehlo-size, and swaks.

This is what I tested:

–jeroen

Posted in *nix, *nix-tools, Awk, bash, bash, Communications Development, Development, DNS, Encryption, grep, HTTPS/TLS security, Internet, Internet protocol suite, Power User, Scripting, Security, SMTP, Software Development, SSH, ssh/sshd, TCP, testssl.sh, TLS | Leave a Comment »

Filippo Valsorda on Twitter: “whoami.filippo.io , the SSH server that knows who you are … Try it out! $ ssh http://whoami.filippo.io”

Posted by jpluimers on 2021/10/20

[Archive.is] Filippo Valsorda on Twitter: “whoami.filippo.io , the SSH server that knows who you are, got some newly refreshed intel! Try it out! $ ssh whoami.filippo.io “

The server itself has some HTML with information too whoami.filippo.io redirecting to [WayBack] ssh whoami.filippo.io (source code is at [WayBack] GitHub – FiloSottile/whoami.filippo.io: A ssh server that knows who you are. $ ssh whoami.filippo.io).

It’s a cool open source server written in Golang, that gets all your public ssh keys (ssh automatically transmits those) and tries to map them back to a GitHub account.

In addition it shows you some potential vulnerabilities of your ssh client.

Note that in October 2020, it was temporarily down, but it will be up again: [Archive.is] Filippo Valsorda 💉💉 on Twitter: “Yeah I’m planning to but I can’t give you an ETA I’m afraid. A few weeks, maybe?… “

Thread comments

Some interesting comments in the thread:

Related: [WayBack] Auditing GitHub users’ SSH key quality

Stop presenting public keys

[WayBack] GitHub – FiloSottile/whoami.filippo.io: A ssh server that knows who you are. $ ssh whoami.filippo.io: How do I stop passing public keys

How do I stop it?

If this behavior is problematic for you, you can tell ssh not to present your public keys to the server by default.

Add these lines at the end of your ~/.ssh/config (after other “Host” directives)

Host *
    PubkeyAuthentication no
    IdentitiesOnly yes

And then specify what keys should be used for each host

Host example.com
    PubkeyAuthentication yes
    IdentityFile ~/.ssh/id_rsa
    # IdentitiesOnly yes # Enable ssh-agent (PKCS11 etc.) keys

If you want you can use different keys so that they can’t be linked together

Host github.com
    PubkeyAuthentication yes
    IdentityFile ~/.ssh/github_id_rsa

–jeroen

Read the rest of this entry »

Posted in *nix, *nix-tools, Communications Development, Development, Go (golang), Internet protocol suite, Power User, Software Development, SSH, ssh/sshd, TCP | Leave a Comment »

Auto connect SSH without autossh?

Posted by jpluimers on 2021/08/10

Hopefully an example ssh config will follow.

[WayBack] Jeroen Pluimers on Twitter: “Would you mind sharing a trimmed down version of your ~/.ssh/config file? The bits from your posts are a bit fragmented now, so I’ve lost the overview (:”

–jeroen

Read the rest of this entry »

Posted in *nix, Communications Development, Development, Internet protocol suite, Power User, SSH, ssh/sshd, TCP | Leave a Comment »

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