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SSH

Setup⚑

Create SSH key⚑

ssh-keygen -t ed25519 -b 4096 -o -a 1000 -C "{username}" -f .ssh/{file}

Usage⚑

Connecting⚑

Force password login⚑

ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no [host]

unix-stack_echange

Jumping through a host⚑

ssh -J [host1] [host2]

wiki-gentoo

SSH tunneling⚑

Make Remote Resources Accessible on Your Local System⚑

ssh -L local_port:remote_address:remote_port username@server.com

Config⚑

Multiple similar entries⚑

If you have multiple similar entries, they can share the common part:

Host X01
    HostName X01.YYY.com

Host X02
    HostName X02.YYY.com

...

Host X01 X02 ...
     User my_username
     Compression yes
     Ciphers arcfour,blowfish-cbc
     Protocol 2
     ControlMaster auto
     ControlPath ~/.ssh/%r@%h:%p
     IdentityFile ~/.ssh/YYY/id_rsa

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Conflicting remote host keys on the same IP⚑

If you have different servers that use the same IP (at different times maybe), you'll have some annoying security alerts about their keys not matching with the previously stored one (since you only can save one of them). What you can do without risking the connection security is adding thes hosts like this in your ~/.ssh/config:

Host server1
  Hostname x1.example.com
  HostKeyAlias server1
  CheckHostIP no
  Port 22001
  User karl

Host server2
  Hostname x2.example.com
  HostKeyAlias server2
  CheckHostIP no
  Port 22002
  User karl

The important part is the HostKeyAlias line, that allows the SSH client to store the remote server public keys with the alias instead of with the unique shared IP address.

stackoverflow

Dynamic IP host verification⚑

When you have a dynamic IP host, you might get Warning: the [whatever] host key for '[host]' differs from the key for the IP address that is true, but also pretty annoying. If you'd rather just verify a host by its keys, instead of keys+IP, try with:

Host nickname
   HostName example.dynamic.tld
   CheckHostIP no

Debug⚑

Ctrl+s hangs the terminal⚑

From vimdoc:

Note: CTRL-S does not work on all terminals and might block
                further input, use CTRL-Q to get going again.

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