SSH

General

• http://en.wikipedia.org/wiki/Secure_Shell
• https://wiki.archlinux.org/index.php/Secure_Shell

ssh user@host

ssh user@host -p 123
 # specify alternate port

• O'Reilly's SSH, The Secure Shell: The Definitive Guide: 1.5. History of SSH
• http://blog.hyfather.com/blog/2013/04/18/ssh-uses-four-tcp-segments-for-each-character/

• http://www.danielmiessler.com/blog/putting-ssh-another-port-good-idea [1]

• https://stribika.github.io/2015/01/04/secure-secure-shell.html

• https://medium.com/@shazow/ssh-how-does-it-even-9e43586e4ffc#.czq2ci4rw [] [2] [3]

• https://news.ycombinator.com/item?id=12482212

Server and client

• http://www.openssh.org/
  • http://en.wikipedia.org/wiki/OpenSSH

The OpenSSH suite consists of the following tools:

• Remote operations are done using ssh, scp, and sftp.
• Key management with ssh-add, ssh-keysign, ssh-keyscan, and ssh-keygen.
• The service side consists of sshd, sftp-server, and ssh-agent.

• Dropbear is a relatively small SSH server and client. It runs on a variety of POSIX-based platforms. Dropbear is open source software, distributed under a MIT-style license. Dropbear is particularly useful for "embedded"-type Linux (or other Unix) systems, such as wireless routers.
  • http://en.wikipedia.org/wiki/Dropbear_(software)

Server

• https://github.com/gravitational/teleport
  • http://blog.gravitational.com/gravitational-teleport-1-0-released/

Client

• http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

• http://sourceforge.net/projects/rutty/

• http://www.9bis.net/kitty/

Management

storm

• storm is a command line tool to manage your ssh connections. features; adding, editing, deleting, listing, searching across your SSHConfig. command alias support for your CLI preferences. support for custom SSH directives. scriptable as a python library.

user interfaces besides cli. (web ui, wxpython, unity(ubuntu) indicator.) [4]

multissh

• multissh - A really short but useful shellscript for connecting to all nodes of a cluster using ssh (also thru gateways and trapdoors) and sending commands to all nodes in parallel. It's using DCOP to remote-control a konsole process with the ssh connections in seperate tabs.

Keys

• https://wiki.archlinux.org/index.php/SSH_Keys

Default file name format;

~/.ssh/id_rsa and ~/.ssh/id_rsa.pub
  RSA key

~/.ssh/identity and ~/.ssh/identity.pub
  DSA key (old)

Creating

ssh-keygen
  create a key. rsa is default.

Distributing

ssh-copy-id [-i [identity_file]] [user@]remote

ssh-copy-id username@remote-server.org

ssh-copy-id 'user@remote-server.org -p 8129'

ssh-copy-id -i ~/.ssh/id_ecdsa.pub '-p 221 username@remote-server.org'

• sshexport [5]

Multiple keys

ssh -i ~/.ssh/id_rsa_example.org

Config

~/.ssh/config

Host example.org
 IdentityFile ~/.ssh/id_rsa_example.org

• http://nerderati.com/2011/03/simplify-your-life-with-an-ssh-config-file/

• sshit - A quick way to manage .ssh/config

SSH agent

• http://en.wikipedia.org/wiki/Ssh-agent

• https://wiki.archlinux.org/index.php/SSH_Keys#SSH_agents

• https://wiki.archlinux.org/index.php/SSH_keys#Start_ssh-agent_with_systemd_user

• http://www.funtoo.org/Keychain

• https://github.com/authy/authy-ssh

• http://www.unixwiz.net/techtips/ssh-agent-forwarding.html

• http://unixwiz.net/techtips/ssh-agent-forwarding.html

• https://heipei.github.io/2015/02/26/SSH-Agent-Forwarding-considered-harmful/

• Envoy helps you to manage ssh keys in similar fashion to keychain, but done in c, takes advantage of cgroups and systemd.

to sort

• ietf: Managing SSH Keys for Automated Access - Current Recommended Practice

• SSH Can Do That? Productivity Tips for Working with Remote Servers
• Tips for Remote Unix Work (SSH, screen, and VNC) [6]

• http://blog.hypergeometric.com/2012/02/22/ssh-dos-and-donts/
• http://www.cyberciti.biz/tips/linux-unix-bsd-openssh-server-best-practices.html

• http://opensourcehacker.com/2012/10/24/ssh-key-and-passwordless-login-basics-for-developers/
• http://vimeo.com/54505525

• HOWTO: set up ssh keys
• Using Rsync and SSH - Keys, Validating, and Automation
• http://www.karan.org/blog/index.php/2009/08/25/multiple-ssh-private-keys

• http://www.cmdln.org/2008/02/11/restricting-ssh-commands/
  • http://www.hackinglinuxexposed.com/articles/20030115.html
  • https://github.com/gabor-udvari/authprogs
    • https://raw.github.com/gabor-udvari/authprogs/master/authprogs

• http://linux.die.net/man/1/ssh-keyscan

• https://github.com/duncs/clusterssh

• https://github.com/apenwarr/sshuttle

• http://alicious.com/cheap-vpn-using-sshuttle/

• http://www.everythingcli.org/ssh-tunnelling-for-fun-and-profit-autossh/

randomart

VisualHostKey=yes

• http://superuser.com/questions/22535/what-is-randomart-produced-by-ssh-keygen
  • http://www.dirk-loss.de/sshvis/drunken_bishop.pdf

SCP

scp -P [port] file.txt user@remotehose:~/file.txt

When scp on remote is initiated, it done so with -t flag, which is undocumented but might be required for precise command persmission configuration.

• https://blogs.oracle.com/janp/entry/how_the_scp_protocol_works

• http://www.psc.edu/index.php/hpn-ssh [7]

SSHFS

• http://fuse.sourceforge.net/sshfs.html
  • http://en.wikipedia.org/wiki/SSHFS

sshfs user@address:/home/user/dir dirtomountto -p [port]
  mount

fusermount -u dirtomountto
  unmount

• Notes on SSHFS

if

fuse: failed to open /dev/fuse: Permission denied

do

usermod -G fuse [username]

and relogin

• https://github.com/hellekin/autosshfs

Security

• http://www.semicomplete.com/articles/ssh-security/

• http://blog.sucuri.net/2013/07/ssh-brute-force-the-10-year-old-attack-that-still-persists.html

fail2ban

• https://wiki.archlinux.org/index.php/Fail2ban

sshguard

• http://www.sshguard.net/
  • https://wiki.archlinux.org/index.php/Sshguard

Honeypot

• https://code.google.com/p/kippo/
  • http://blog.macuyiko.com/2011/03/running-ssh-honeypot-with-kippo-lets.html

TOTP port fluxing

• TOTP SSH port fluxing [8]

X11 forwarding

See GUI#X Forwarding

Web forwarding

• https://github.com/apenwarr/sshuttle

• http://bbrinck.com/post/2318562750/reverse-ssh-tunneling-easier-than-port-forwarding

Tools

• http://www.harding.motd.ca/autossh/

• http://matt.ucc.asn.au/ssh-xfer/
  • http://archive09.linux.com/feature/143892

• https://github.com/turicas/sbc

To sort

• https://wiki.archlinux.org/index.php/Shfs - older Linux kernel module which allows you to mount remote filesystems using a plain shell (ssh) connection