(PECL ssh2 >= 0.9.0)

ssh2_connectConnect to an SSH server


resource ssh2_connect ( string $host [, int $port = 22 [, array $methods [, array $callbacks ]]] )

Establish a connection to a remote SSH server.

Once connected, the client should verify the server's hostkey using ssh2_fingerprint(), then authenticate using either password or public key.





methods may be an associative array with up to four parameters as described below.

methods may be an associative array with any or all of the following parameters.
Index Meaning Supported Values*
kex List of key exchange methods to advertise, comma separated in order of preference. diffie-hellman-group1-sha1, diffie-hellman-group14-sha1, and diffie-hellman-group-exchange-sha1
hostkey List of hostkey methods to advertise, comma separated in order of preference. ssh-rsa and ssh-dss
client_to_server Associative array containing crypt, compression, and message authentication code (MAC) method preferences for messages sent from client to server.  
server_to_client Associative array containing crypt, compression, and message authentication code (MAC) method preferences for messages sent from server to client.  

* - Supported Values are dependent on methods supported by underlying library. See » libssh2 documentation for additional information.

client_to_server and server_to_client may be an associative array with any or all of the following parameters.
Index Meaning Supported Values*
crypt List of crypto methods to advertise, comma separated in order of preference., aes256-cbc, aes192-cbc, aes128-cbc, 3des-cbc, blowfish-cbc, cast128-cbc, arcfour, and none**
comp List of compression methods to advertise, comma separated in order of preference. zlib and none
mac List of MAC methods to advertise, comma separated in order of preference. hmac-sha1, hmac-sha1-96, hmac-ripemd160,, and none**

Note: Crypt and MAC method "none"

For security reasons, none is disabled by the underlying » libssh2 library unless explicitly enabled during build time by using the appropriate ./configure options. See documentation for the underlying library for more information.


callbacks may be an associative array with any or all of the following parameters.

Callbacks parameters
Index Meaning Prototype
ignore Name of function to call when an SSH2_MSG_IGNORE packet is received void ignore_cb($message)
debug Name of function to call when an SSH2_MSG_DEBUG packet is received void debug_cb($message, $language, $always_display)
macerror Name of function to call when a packet is received but the message authentication code failed. If the callback returns TRUE, the mismatch will be ignored, otherwise the connection will be terminated. bool macerror_cb($packet)
disconnect Name of function to call when an SSH2_MSG_DISCONNECT packet is received void disconnect_cb($reason, $message, $language)

Return Values

Returns a resource on success, or FALSE on error.


Example #1 ssh2_connect() example

Open a connection forcing 3des-cbc when sending packets, any strength aes cipher when receiving packets, no compression in either direction, and Group1 key exchange.

/* Notify the user if the server terminates the connection */
function my_ssh_disconnect($reason$message$language) {
printf("Server disconnected with reason code [%d] and message: %s\n",

$methods = array(
'kex' => 'diffie-hellman-group1-sha1',
'client_to_server' => array(
'crypt' => '3des-cbc',
'comp' => 'none'),
'server_to_client' => array(
'crypt' => 'aes256-cbc,aes192-cbc,aes128-cbc',
'comp' => 'none'));

$callbacks = array('disconnect' => 'my_ssh_disconnect');

$connection ssh2_connect(''22$methods$callbacks);
if (!
$connection) die('Connection failed');

See Also

add a note add a note

User Contributed Notes 5 notes

Steve Kamerman
5 years ago
Due to a lack of complete examples, here's a simple SSH2 class for connecting to a server, authenticating with public key authentication, verifying the server's fingerprint, issuing commands and reading their STDOUT and properly disconnecting.  Note: You may need to make sure you commands produce output so the response can be pulled.  Some people suggest that the command is not executed until you pull the response back.
class NiceSSH {
// SSH Host
private $ssh_host = '';
// SSH Port
private $ssh_port = 22;
// SSH Server Fingerprint
private $ssh_server_fp = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
// SSH Username
private $ssh_auth_user = 'username';
// SSH Public Key File
private $ssh_auth_pub = '/home/username/.ssh/';
// SSH Private Key File
private $ssh_auth_priv = '/home/username/.ssh/id_rsa';
// SSH Private Key Passphrase (null == no passphrase)
private $ssh_auth_pass;
// SSH Connection
private $connection;
    public function
connect() {
        if (!(
$this->connection = ssh2_connect($this->ssh_host, $this->ssh_port))) {
            throw new
Exception('Cannot connect to server');
$fingerprint = ssh2_fingerprint($this->connection, SSH2_FINGERPRINT_MD5 | SSH2_FINGERPRINT_HEX);
        if (
strcmp($this->ssh_server_fp, $fingerprint) !== 0) {
            throw new
Exception('Unable to verify server identity!');
        if (!
ssh2_auth_pubkey_file($this->connection, $this->ssh_auth_user, $this->ssh_auth_pub, $this->ssh_auth_priv, $this->ssh_auth_pass)) {
            throw new
Exception('Autentication rejected by server');
    public function
exec($cmd) {
        if (!(
$stream = ssh2_exec($this->connection, $cmd))) {
            throw new
Exception('SSH command failed');
stream_set_blocking($stream, true);
$data = "";
        while (
$buf = fread($stream, 4096)) {
$data .= $buf;
    public function
disconnect() {
$this->exec('echo "EXITING" && exit;');
$this->connection = null;
    public function
__destruct() {

[EDIT BY danbrown AT php DOT net: Contains two bugfixes suggested by 'AlainC' in user note #109185 (removed) on 26-JUN-2012.]
thessoro at gmail dot com
1 year ago
Be careful when providing a specific hostkey order.

('IP', 'port', array('hostkey'=>'ssh-rsa, ssh-dss'));

Will only work when the public key of the server is RSA, and not DSA also as expected. This is caused by the empty space before the "ssh-dss".

So a similar code:

('IP', 'port',   array('hostkey'=>'ssh-rsa,ssh-dss'));

Will work. The HOSTKEY method is overriden using exactly what you write, so no empty spaces are allowed.

This took me some time that you could save ;)
Trev White
3 years ago
If you are having problems with running a ssh2 session and it waits forever during the execution of stream_get_contents, it might be because the remote system has run the command and is now sitting at a # prompt waiting for the next command.  I had this issue on a HP MSA box, here is the code to get around the issue.

Assuming you are connected with your authentication method and $ssh contains the handle.

= "check disk";
// Open a nice large window to stop wrapping
$stream = ssh2_shell ($ssh, 'xterm', null, 200, 200, SSH2_TERM_UNIT_CHARS);

// Hook into the error stream
$errorStream = ssh2_fetch_stream($stream, SSH2_STREAM_STDERR); 

// Block the streams so we wait until they complete
stream_set_blocking ($stream, true);
stream_set_blocking($errorStream, true);

// Send the commands to the terminal
fwrite ($stream, $command . PHP_EOL );

// Wait give the terminal a chance to accept and start processing the command, this is a slow storage device after all

// IMPORTANT BIT!!  Send exit to the terminal to close the connection BEFORE WE WAIT FOR THE STREAM
fwrite ($stream, "exit" . PHP_EOL );
sleep (2);

// Print the output
echo stream_get_contents($stream);

if (
strlen($errortext) > 0) {
// Error Data
echo "Error Data: $errortext";
         exit (

// All Good
exit (0);


You can't use ssh2_exec with this method (well at lease I couldn't) because on executing the first command the stream gets blocked and then you can't run the exit command, whereas a terminal seems to use one session.

I hope this helps someone.
rainerkrauss at googlemail dot com
2 years ago
Warning! If you open a ssh connection and execute an external program opening another ssh connection it may result in very strange behavior.

I used an sftp connection to get a file list and used "exec" to download the files afterwards with an external sftp. lftp downloaded zeros with no comment, psftp exits with error code 11 most of the time, but sometimes it works - probably depending on how quickly php collects garbage and closes the unused connection first.

As there is no function to close a connection, you need to be sure to destroy all references (unset) to close it.
suri dot suribala dot com
11 years ago
With Sara's help, I have the following SS2 class that is quite flexible. If anyone improves it, please feel free to let me know.


// ssh protocols
// note: once openShell method is used, cmdExec does not work

class ssh2 {

$host = 'host';
$user = 'user';
$port = '22';
$password = 'password';
$con = null;
$shell_type = 'xterm';
$shell = null;
$log = '';

__construct($host='', $port=''  ) {

$host!='' ) $this->host  = $host;
$port!='' ) $this->port  = $port;

$this->con  = ssh2_connect($this->host, $this->port);
     if( !
$this->con ) {
$this->log .= "Connection failed !";


authPassword( $user = '', $password = '' ) {

$user!='' ) $this->user  = $user;
$password!='' ) $this->password  = $password;

     if( !
ssh2_auth_password( $this->con, $this->user, $this->password ) ) {
$this->log .= "Authorization failed !";


openShell( $shell_type = '' ) {

        if (
$shell_type != '' ) $this->shell_type = $shell_type;
$this->shell = ssh2_shell( $this->con$this->shell_type );
    if( !
$this->shell ) $this->log .= " Shell connection failed !";


writeShell( $command = '' ) {

fwrite($this->shell, $command."\n");


cmdExec( ) {

$argc = func_num_args();
$argv = func_get_args();

$cmd = '';
$i=0; $i<$argc ; $i++) {
$i != ($argc-1) ) {
$cmd .= $argv[$i]." && ";
$cmd .= $argv[$i];

$stream = ssh2_exec( $this->con, $cmd );
stream_set_blocking( $stream, true );
fread( $stream, 4096 );


getLog() {




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