Ssh on Nico Maas

fail2ban Cheat Sheet

Wed, 17 Feb 2021 10:22:00 +0000

Just the commands I always need to look up, because I forgot again…

Overview over fail2ban status and jails

fail2ban-client status

See which e.g. IPs are banned for sshd jail

fail2ban-client status sshd

Unban an IP from sshd jail

fail2ban-client set sshd unbanip IPADDRESSHERE

See which systems are actually banned

zgrep 'Ban' /var/log/fail2ban.log*

[Win10] Offline installation of FoD like OpenSSH Server without VLSC ISO

Thu, 11 Feb 2021 17:00:00 +0000

Windows 10 comes with a lot of additional options to install, which are not part of the “local” installation media.That means things like e.g. the OpenSSH Server component. These options are called “Features on Demand” (FoD) and do need either an active internet connection to download and install, or a specialized FoD ISO which you only can download from the Microsoft Volume Licensing Service Center (VLSC). If you need to install these options for your Windows 10 Professional or similar offline - without having a valid subscription, you cannot get the needed offline files that way.

SSH config for beginners

Tue, 18 Apr 2017 12:00:06 +0000

The SSH config is a powerful tool to get “more” out of your normal SSH connection.

Just create an file called “config” in your .ssh folder and it will be used on a new SSH session.

Lets start with a simple example of how a connection configuration could look like:

Host myHost
  Hostname 1.2.3.4 
  IdentityFile ~/.ssh/myHostKey
  User myUser

With this code, an “ssh myHost” will try to connect to the host 1.2.3.4 - using the user myUser and the keyfile myHostKey. And with this - you can use multiple keys and users on the same host without too much trouble 🙂

[Ubuntu] Use Molly-Guard to stop shooting your own leg

Fri, 23 Sep 2016 08:00:06 +0000

If you’re working on some dozens of linux servers (or even more than 100,.. as in my case), you end up doing administration via SSH - which is the way to go. And chances are, that you’ll get dozens of SSH connections open in dozens of tabs and you did some updates on some of those servers and want to restart this thing with a quick sudo reboot now…
I won’t lie if I say, it happend more than once that I accidentally rebooted the wrong server - at least that was the case more than a year ago.
For the last year, since I have been using Molly-Guard - that did not happen once. Why? Because Molly-Guard does stop the reboot command if it detects that you’re issuing it from an SSH console - and asks for the server name. If you’re entering it correctly - it will reboot. If you’re in a frenzy, doing your “sudo reboot now” and enter name serverB while you’re on serverA - yep, Molly-Guard will stop you from shooting yourself in the leg. Neat, ain’t it?

SSH Socks Proxy

Mon, 23 Mar 2015 15:01:08 +0000

Very easy and handy is to use an SSH Server as Socks Proxy:

ssh -D 8080 username@my_ssh_server

Or use Putty:
Enter the IP Address of your SSH Server, Port and go to Connection -> SSH -> Tunnels.
In Source Port enter the Port where the Proxy should be available. I.e. 8080
Then choose “Dynamic”.
Leave Destination Port Empty and the IP Configuration on “Auto”.

After connecting to your SSH Server, you can configure i.e. Firefox to use your Socks 5 Server on IP 127.0.0.1 and Port 8080.

[Linux] Delete old SSH Keys and recreate them

Sat, 14 Mar 2015 13:07:08 +0000

If you are downloading an Linux Image for i.e. Embedded Systems like Raspberry Pi, sometimes, the SSH Keys are still on the system and are not recreated.
To do that manually, just enter:

sudo rm /etc/ssh/ssh_host_*
sudo dpkg-reconfigure openssh-server
sudo service ssh restart

[Putty] Multiple Tabs with Putty

Wed, 06 Jul 2011 09:59:00 +0000

An “Multi-Tab” Putty Version?
Does that exist?
No - putty does not do tabs, neither any custom version.
But theres an so called “Putty Connection Manager” which does mange your Sessions 256 bit AES encrypted as well as do Multiple Tabs via wrapping Putty multiple times within itself! http://puttycm.free.fr/cms/index.php

[pfSense] Access with SCP

Sat, 16 Apr 2011 09:00:46 +0000

If you need to access your pfSense with WinSCP (i.e.), activate SSH in pfSense first.
After that, you can log in with the Account root (!!!) and your Webconfiguration password.
Yeah, that saved my day after hours of trying to… “work-around”.

[ESXi 3.5] ESXi 3.5 Update 5 Install CD with oem.tgz + ssh,ftp,rsync and wget (made easy)!

Tue, 30 Mar 2010 14:41:53 +0000

Hello,

It has been a while since I was really doing something new with VMWare, but as I had the need to install some new Servers, I also was looking for better ways on integrating oem.tgz and other features. For that, I stumbled upon an very cool and useful Linux Build Script for ESXi, made by the User Varazir. After this How To you’re going to hold an ISO Installer with SSH, FTP, RSYNC, WGET and the Community Unified Driver Pack 1.1.0 oem.tgz in your Hands. Or an USB Stick with the same features - as Live Boot or Installer. Your choice.

SSH Tunneling

Wed, 06 Jan 2010 12:30:44 +0000

One of the most important things by working in “dangerous” Networking Enviroments is protection.

And by that I don’t mean the usual (and important!) Anti Virus, Anti Malware and Firewall Software, but Traffic Tunneling, meaning VPN or SSH.

SSH is the secure equivalent to the good old (and Plaintext transmitted) Telnet. And its also more powerful: Its use is not limited to remote Control, but can also provide an secured Datatunnel through which all your Traffic to your Remote Location (i.e. an Mysql Database, Web- or Mailserver or the Web itself) is tunneld - and encrypted. Giving therefore little to no chance to “Wiresharkes” and other Cable Tappers or Span Users.