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adds ssh config info

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waldek 2021-07-13 15:16:01 +02:00
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modules/qualifying/learning_ssh.md
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@ -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