diff --git a/modules/qualifying/learning_ssh.md b/modules/qualifying/learning_ssh.md index 0290b86..b88b802 100644 --- a/modules/qualifying/learning_ssh.md +++ b/modules/qualifying/learning_ssh.md @@ -260,6 +260,65 @@ I'll let you figure it out by yourself but if you're stuck have a look at [this] ## Standard usage +The basic usage of ssh is what you've been doing up until now, logging into remote machines. +Now that you know how to add keys for automated logins, it's time to learn a few handy tricks. +The first one is a bit basic but handy non the less. +You can add a command to execute after the `ssh $USER@$HOST` so it becomes as follows. +In this particular case it shows me information about the mounted partitions. + +``` +➜ ~ git:(master) ✗ ssh waldek@172.30.4.19 df -h +Filesystem Size Used Avail Use% Mounted on +udev 16G 0 16G 0% /dev +tmpfs 3.2G 347M 2.8G 11% /run +/dev/sda1 219G 99G 109G 48% / +tmpfs 16G 16K 16G 1% /dev/shm +tmpfs 5.0M 0 5.0M 0% /run/lock +tmpfs 16G 0 16G 0% /sys/fs/cgroup +tank 386G 128K 386G 1% /usr/share/zpool +tank/set1 573G 187G 386G 33% /usr/share/zpool/set1 +tank/set2 386G 128K 386G 1% /usr/share/zpool/set2 +tank/set3 100M 128K 100M 1% /usr/share/zpool/set3 +tmpfs 3.2G 0 3.2G 0% /run/user/1000 +➜ ~ git:(master) ✗ +``` + +A second nice thing to know about is the `~/.ssh/config` file. +In this file you can add shortcut's to hosts you often contact. +As an example I would like to add a shortcut to my matrix server. + +``` +➜ ~ git:(master) ✗ ssh matrixserver +ssh: Could not resolve hostname matrixserver: No address associated with hostname +``` + +To create the shortcut I append the following to my `~/.ssh/config` file. + +``` +Host matrixserver + Hostname 172.30.4.19 + Port 22 + User waldek + IdentityFile ~/.ssh/id_rsa +``` + +I can now log in as follows. + +``` +➜ ~ git:(master) ✗ ssh matrixserver +Linux debian 4.19.0-16-amd64 #1 SMP Debian 4.19.181-1 (2021-03-19) x86_64 + +The programs included with the Debian GNU/Linux system are free software; +the exact distribution terms for each program are described in the +individual files in /usr/share/doc/*/copyright. + +Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent +permitted by applicable law. +You have new mail. +Last login: Tue Jul 13 14:12:18 2021 from 172.30.40.99 +➜ ~ +``` + ## Tweaking the sshd configuration file All server configuration is done in the `/etc/ssh/sshd_config` file. @@ -283,6 +342,10 @@ Protocol “2,1” is identical to “1,2”. ``` +### Some classic security enhancements + +### Tunneling and X forward + ## Tunnels ## SFTP