====== SSH ======

===== SSH Configuration =====

==== SSH Daemon ====
Config File: ''/etc/ssh/sshd_config'' \\
\\
Allow root login to server
  PermitRootLogin yes
\\

==== SSH Client ====
Config File: ''/etc/ssh/ssh_config'' \\
\\
Do not use the '~' escape character
  EscapeChar none
This can also be achived by ''ssh //-e none// <user>@<ip>''
\\

===== General SSH Functions =====

==== SSH to remote host without entering password ====
Generate a private key if not already done. This can be achived with the ''//ssh-keygen//'' command. Should a key already exist, you'll get warned and can abort.

<Code:none>
srohr@pidev01:~ $ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/srohr/.ssh/id_rsa): 
/home/srohr/.ssh/id_rsa already exists.
Overwrite (y/n)? n
srohr@pidev01:~ $ 
</Code>
\\
Create a new key.
<Code:none>
srohr@pidev01:~ $ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/srohr/.ssh/id_rsa): 
Created directory '/home/srohr/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/srohr/.ssh/id_rsa
Your public key has been saved in /home/srohr/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:KGwUqdYbQVXRG2bnM4NifhhHixn0QjYgB6wMUPr0xj8 srohr@pidev01
The key's randomart image is:
+---[RSA 3072]----+
|o..o=+++Bo       |
|..  ++ o.o* .    |
|.o.+..  .B.B     |
| o==o  .*.= =    |
| .. Bo.oS=   +   |
|   o.o  o .      |
|      E  .       |
|       .         |
|                 |
+----[SHA256]-----+
srohr@pidev01:~ $ 
</Code>
\\
On your client, use the ''//ssh-copy-id//'' command to copy your public key to the server you want to connect to.
<Code:none>
srohr@mars:~$ ssh-copy-id srohr@192.168.16.6
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
srohr@192.168.16.6's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'srohr@192.168.16.6'"
and check to make sure that only the key(s) you wanted were added.

srohr@mars:~$ 
</Code>
\\
It is now possible to ssh to the remote machine without entering a password.
<Code:none>
srohr@mars:~$ ssh srohr@192.168.16.6
Linux pidev01 6.1.0-rpi7-rpi-v8 #1 SMP PREEMPT Debian 1:6.1.63-1+rpt1 (2023-11-24) aarch64

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.
Last login: Fri Dec 15 10:17:26 2023 from 192.168.16.15
srohr@pidev01:~ $ 
</Code>