Tcl

Send an SSH IGNORE Message

Demonstrates the Chilkat Ssh.SendIgnore method, which sends an SSH IGNORE message. It takes no arguments. The server does not reply, but a successful send helps confirm the connection is still writable. No channel is required.

Background: The SSH IGNORE message is discarded by the peer by design; its usefulness is as a lightweight keep-alive or liveness probe. Because it exercises the actual write path, a successful SendIgnore is stronger evidence than CheckConnection that the link is still usable, without side effects on any channel.

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Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the Ssh.SendIgnore method, which sends an SSH IGNORE message.  It takes no
#  arguments.  The server does not reply, but a successful send helps confirm the connection is
#  still writable.  No channel is required.

set ssh [new_CkSsh]

#  Connect to the SSH server.  Port 22 is the usual SSH port.
set sshPort 22
set success [CkSsh_Connect $ssh "ssh.example.com" $sshPort]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

#  Normally you would not hard-code the password in source.  You should instead obtain it
#  from an interactive prompt, environment variable, or a secrets vault.
set password "mySshPassword"

set success [CkSsh_AuthenticatePw $ssh "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

#  Send an IGNORE message to verify the connection is still writable.
set success [CkSsh_SendIgnore $ssh]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

puts "IGNORE message sent."

CkSsh_Disconnect $ssh

delete_CkSsh $ssh