I'd like to speed up connecting to specific servers.
I have the servers let's say:
123.123.123.1
123.123.123.2
123.123.123.3I normally connect with the following:
ssh -p 12345 my_user@123.123.123.1This is a pain because the only difference between the servers is the last number of the ip.
I tried the following code:
alias ssht='{ ip=$(cat -); ssh -p 12345 my_user@"123.123.123.$ip"; }<<<'However I get an error:
karl@karls-laptop ~/scripts $ ssht 1
Pseudo-terminal will not be allocated because stdin is not a terminal.Is there a way to get this working?
45 Answers
Use the intended way and write the options and aliases into ~/.ssh/config:
Host 1 Port 12345 User my_user HostName 123.123.123.1
Host 2 Port 12345 User my_user HostName 123.123.123.2and so on...
And then connect just using
ssh 1
ssh 2
...This calls for a function -- simple and robust, whereas an alias in this case would be fragile.
Something like this should do:
function ssht () { [[ $1 =~ ^(1|2|3)$ ]] || { echo 'Not a valid last octet value !!' && return ;} ip=123.123.123.$1 ssh my_user@"$ip" -p 12345
}The condition [[ $1 =~ ^(1|2|3)$ ]] makes sure you have entered one of 1, 2, 3 as first argument (any trailing argument is ignored).
Now, you can give the desired last octet as the first argument:
ssht 1
ssht 2
ssht 3Put this in your ~/.bashrc for having it available in any interactive session.
You can use patterns in ~/.ssh/config. From man ssh_config:
PATTERNS A pattern consists of zero or more non-whitespace characters, ‘*’ (a wildcard that matches zero or more characters), or ‘?’ (a wildcard that matches exactly one character). For example, to specify a set of declarations for any host in the “.co.uk” set of domains, the following pattern could be used: Host *.co.uk The following pattern would match any host in the 192.168.0.[0-9] network range: Host 192.168.0.?Combined with:
HostName Specifies the real host name to log into. This can be used to specify nicknames or abbreviations for hosts. If the hostname contains the character sequence ‘%h’, then this will be replaced with the host name specified on the command line (this is useful for manipulating unqualified names). The character sequence ‘%%’ will be replaced by a single ‘%’ character, which may be used when specifying IPv6 link-local addresses.So, in your ~/.ssh/config, put:
Host ? Hostname 123.123.123.%h Port 12345 User my_userThen:
$ ssh -v 1
OpenSSH_7.4p1, LibreSSL 2.5.0
debug1: Reading configuration data /home/muru/.ssh/config
debug1: /home/muru/.ssh/config line 41: Applying options for ?
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to 123.123.123.1 [123.123.123.1] port 12345.
debug1: connect to address 123.123.123.1 port 12345: Connection refused
ssh: connect to host 123.123.123.1 port 12345: Connection refusedUse a function instead :
function ssht(){ ssh -p 12345 my_user@123.123.123.$1
}$ ssht 1
$ ssht 2
$ ...A better solution is to use a ssh config file:
touch ~/.ssh/configwith some lines similar to:
Host some-name HostName 123.123.123.1 User your_user Port 22You can also use ssh keys to improve the speed, finally you only run:
ssh some-nameand you are connected to that server.
2You don't even need to use a name like ssht. Names starting with digits, even only digits are valid hostnames in ssh config file.
Below works on Xubuntu Xenial
Part of my ~/.ssh/config
Host 1 Hostname bastion.example.me User said Port 22 IdentityFile ~/.ssh/id_rsa ForwardAgent yesCommand I run (below I added -vv for verbose logging to STDOUT a.k.a your screen by default)
ssh -vv 1Output
OpenSSH_7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g 1 Mar 2016
debug1: Reading configuration data /home/said/.ssh/config
debug1: /home/said/.ssh/config line 24: Applying options for 1
debug1: /home/said/.ssh/config line 540: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "bastion.example.me" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to bastion.example.me [XXX.YYY.120.51] port 22.
debug1: Connection established.
debug1: identity file /home/said/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/said/.ssh/id_rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.2
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.2 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to bastion.example.me:22 as 'said'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ,,,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,,,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: ,aes128-ctr,aes192-ctr,aes256-ctr,,,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc: ,aes128-ctr,aes192-ctr,aes256-ctr,,,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,,zlib
debug2: compression stoc: none,,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: ,aes128-ctr,aes192-ctr,aes256-ctr,,
debug2: ciphers stoc: ,aes128-ctr,aes192-ctr,aes256-ctr,,
debug2: MACs ctos: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: ,,,,,,,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,
debug2: compression stoc: none,
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm:
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: MAC: <implicit> compression: none
debug1: kex: client->server cipher: MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:44tChrTUMwuRcOi6laiYlf6VM3qAD+PEn9EdNMribFw
debug1: Host 'bastion.example.me' is known and matches the ECDSA host key.
debug1: Found key in /home/said/.ssh/known_hosts:69
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug2: key: /home/said/.ssh/id_rsa (0x562c764294f0), explicit, agent
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/said/.ssh/id_rsa
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug2: input_userauth_pk_ok: fp SHA256:KQNLYiJICyNbKmIxVVgc67RF+qRKjNi3w+0iXz/YDyk
debug1: Authentication succeeded (publickey).
Authenticated to bastion.example.me ([XXX.YYY.120.51]:22).
debug1: channel 0: new [client-session]
debug2: channel 0: send open
debug1: Requesting
debug1: Entering interactive session.
debug1: pledge: network
debug1: client_input_global_request: rtype want_reply 0
debug2: callback start
debug1: Requesting authentication agent forwarding.
debug2: channel 0: request confirm 0
debug2: fd 3 setting TCP_NODELAY
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug2: channel 0: request shell confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.8.0-42-lowlatency x86_64)
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$Update - below is a hackish alternative solution, take it just for bashist exercise, maybe for quick and dirty stuff:
alias ssht='f(){ ssh -p 22 said@192.168.0.$@;unset -f f;}&&f'What it does
- Create temporary function
- Pass all arguments to it
- Do the SSH connection
- Once session ends, unset the function so it won't linger around
- It can take additional arguments, meaning you can chain additional ssh options like tunneling (
-L,-R,-D), verbose mode (-vv), no-TTY (-T) etc.
For example I want to start a socks proxy with no terminal
$ ssht 2 -vv -D 1080 -T
OpenSSH_7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g 1 Mar 2016
debug1: Reading configuration data /home/said/.ssh/config
debug1: /home/said/.ssh/config line 540: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "192.168.0.2" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 192.168.0.2 [192.168.0.2] port 22.
debug1: Connection established.
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Welcome to Linux Mint 18.1 Serena (GNU/Linux 4.4.0-81-generic x86_64) * Documentation:
98 packages can be updated.
0 updates are security updates.As you can see, no command prompt, it executed with -vv,-T,-D 1080 arguments.
I can verify tunnel (basically SOCKS5 proxy) on my machine, too
$ ss -ltnp | grep 1080
LISTEN 0 128 127.0.0.1:1080 *:* users:(("ssh",pid=17038,fd=6))
