How to Install and Use the PHP SSH2 Extension for Secure Remote Operations

Installation

libssh2 installation

libssh2 is an open‑source C library that implements the SSH client protocol, providing APIs for remote command execution, file transfer, and port forwarding.

wget https://libssh2.org/download/libssh2-1.11.0.tar.gz

tar -zxvf libssh2-1.11.0.tar.gz

cd libssh2-1.11.0/

./configure
make
sudo make install

PHP‑SSH2 installation

Official package page: https://pecl.php.net/package/ssh2

wget https://pecl.php.net/get/ssh2-1.4.tgz

tar -zxvf ssh2-1.4.tgz

cd ssh2-1.4/

/usr/local/php-8.2.14/bin/phpize

./configure --with-php-config=/usr/local/php-8.2.14/bin/php-config

make
make install

Add the extension to php.ini:

extension=ssh2

Verify the installation:

/usr/local/php-8.2.14/bin/php -m|grep ssh2
ssh2

Usage

Connecting to a remote server is the first step when using the PHP SSH2 extension. You must provide the server address, port, username, and password (or an SSH key).

Username and password authentication

$connection = ssh2_connect('tinywan.com', 22);
$res = ssh2_auth_password($connection, "username", "password");
if ($res) {
    echo "Authentication Successful! ";
} else {
    echo "Authentication Failed! ";
    exit(255);
}

SSH key authentication

$connection = ssh2_connect('192.168.1.204', 22, ['hostkey' => 'ssh-rsa']);
$res = ssh2_auth_pubkey_file($connection, 'tinywan', '/home/tinywan/.ssh/id_rsa.pub', '/home/tinywan/.ssh/id_rsa');
if ($res) {
    echo "Public Key Authentication Successful
";
} else {
    echo "Public Key Authentication Failed";
}

Execute a remote command (e.g., ls -l) and capture its output:

$connection = ssh2_connect('tinywan.com', 22);
ssh2_auth_password($connection, 'username', 'password');
$stream = ssh2_exec($connection, 'ls -l');
stream_set_blocking($stream, true);
echo stream_get_contents($stream);

Upload and download files with ssh2_scp_send and ssh2_scp_recv:

$connection = ssh2_connect('tinywan.com', 22);
ssh2_auth_password($connection, 'username', 'password');
ssh2_scp_send($connection, '/local_file', '/remote_file');
ssh2_scp_recv($connection, '/remote_file', '/local_file');

Handle errors during connection, authentication, or file operations:

$connection = ssh2_connect('tinywan.com', 22);
if (!$connection) {
    die('Connection failed.');
}
$auth = ssh2_auth_password($connection, 'username', 'password');
if (!$auth) {
    die('Authentication failed.');
}

The PHP SSH2 extension provides a straightforward way to perform secure remote operations—such as command execution and file transfer—from PHP scripts, making it valuable for server management and deployment workflows, provided that proper error handling is implemented.