keygen

ssh-keygen -b 4096
ssh-keygen -R host  # remove host from `known_hosts`
ssh-keygen -p       # change password for existing key

ssh-agent

ssh-add     # add identity to agent
ssh-add -l  # list identities in agent, `-L` gives actual keys
ssh-add -D  # remove all identities from agent

master connection

<login> is how connection was made, usually it is user@host.

ssh -O check <login>
ssh -O cancel <login>
ssh -O exit <login>
ssh -O stop <login>  # stop accepting new connections without killing current ones

x forwarding

ssh -CY

• -C enables compression
• -Y disables X11 SECURITY extension restrictions

socks proxy

ssh -D 9999 hbschr@hbschr.de

configure firefox to use network SOCKS 5 proxy on localhost:9999

sshfs via fuse

mount point should belong to user. will be mounted as fs fuse.sshfs, specific options like btrfs subvolumes are not accessible.

sshfs heiko@loki:/ /mnt/loki/

host based identity

# in config
Host host
    IdentityFile ~/.ssh/id_host

misc

• cipher: symmetric key, f.e. aes
• mac: message authentication code
• kex: key exchange, f.e. dh
• key: asymmetric key

ssh -Q cipher
ssh -Q mac
ssh -Q kex
ssh -Q key