Issue

I have written a small script that issues a series of commands via write() to a linux machine, with a 5 second sleep() between each one. The exact same commands work when entered manually but despite being connected successfully, do not seem to work when used from a PHP script.

As this is the case, I am curious if using read() is absolutely necessary prior to issuing a write() command?

<?php

include('Net/SSH2.php');

    $serverhostname = "IP_HERE";
    $ssh_username = "root";
    $ssh_password = "PASS_HERE";

    // Establish new SSH2 Connection
    $connection = new Net_SSH2($serverhostname, 22);

    if($connection->login($ssh_username, $ssh_password))
    {
        echo "LOGGED IN! </br>";

        sleep(5);

        $result = $connection->write('en PASS_HERE\r\n');
        echo "RESULT: " . $result . " </br>";

        sleep(5);

        $result = $connection->write('configure terminal\r\n');
        echo "RESULT: " . $result . " </br>";

        sleep(5);

        $result = $connection->write('interface ve 110\r\n');
        echo "RESULT: " . $result . " </br>";

        sleep(5);

        $result = $connection->write('port-name Test_Brett\r\n');
        echo "RESULT: " . $result . " </br>";
    }
    else
    {
        echo "SSH Connection Failed. Check that the remote host is online and accepting connections!";
    }

?>

UPDATE

$result = $connection->write('en PASS_HERE\n');
$result = $connection->write('configure terminal\n');
$result = $connection->write('interface ve 110\n');
$result = $connection->write('port-name Test_Brett\n');
$connection->setTimeout(5);
echo $connection->read();

Solution

I just did this:

$connection->write("ls -la\n");
$connection->write("pwd\n");
$connection->setTimeout(5);
echo $connection->read();

And it seemed to perform the commands just fine without a read() between the two write()'s. But it could be that a read() has to be done, even if just once, at the end.

What I'd do if I were you is, instead of doing sleep(5) do $connection->setTimeout(5); $connection->read();. You can throw away the return value of read(). If you knew what to expect back you could just do $connection->read('pattern'), which would be faster, but if you don't, I'd do the $connection->setTimeout(5); route just to be on the safe side.

Answered By - neubert

Thursday, October 28, 2021

[SOLVED] Is read() necessary before write() with SSH via PHPSecLib?

Issue

Solution