Tunnel Connect Mode controls how a tunnel behaves when a connection attempt originates locally.
For more information on Protocol SSH, see the SSH Client: Users page.
For more information on Protocol SSL, see the SSL page.
A Tunnel in Connect Mode can be started in a number of ways:
Disabled: never started.
Always: always started.
Any Character: started when any character is read on the Serial Line.
Start Character: started when the Start Character is read on the Serial Line.
Modem Control Asserted: started when the Modem Control pin is asserted on the Serial Line.
Modem Emulation: started by an ATD command.
When the Start Character is received on the Serial Line, it connects the tunnel.
The Start Character may be designated as a single printable character or as a control character.
Control characters may be input in any of the following forms:
<control>J or
0xA (hexadecimal) or
\10 (decimal).
Enabling Flush Start Character prevents forwarding of a start character from the Line into the network.
Disabling Flush Start Character allows forwarding of a start character from the Line into the network.
At least one Host is required to enable Connect Mode.
It contains the information necessary to connect to that host.
Click on the displayed information to expand it for editing.
The button
promotes the selected host,
exchanging its place with the host above it,
to adjust the order of the defined hosts.
The Host Address is required to enable Connect Mode.
It designates the address of the remote host to connect to.
Either a DNS address or an IP address may be provided.
The button
promotes the selected host,
exchanging its place with the host above it,
to adjust the order of the defined hosts.
The Host Port is required to enable Connect Mode.
It designates the TCP or UDP port on the remote host to connect to.
The Local Port is by default random but can be overridden.
Blank the field to restore the random default.
The Protocol used on the connection can be one of SSH, SSL, Telnet, TCP, TCP with AES, UDP, or UDP with AES.
If security is a concern it is highly recommended that SSH be used. When using SSH, both the SSH Server Host Keys and SSH Server Authorized Users must be configured.
The SSH Username specifies the SSH Client User to use for an outgoing SSH connection.
The Credentials specifies the name of the set of RSA and/or DSA certificates and keys to be used for the SSL connection.
Enabling Validate Certificate requires the tunnel to verify the remote SSL server certificate when making a connection.
Disabling Validate Certificate causes the tunnel to skip verification of the remote SSL server certificate.
The TCP Initial Keep Alive timer, also known as the TCP Keep Alive Idle Time, specifies how long to wait before the first Keep Alive probe is sent to the remote host in order to keep the TCP connection up during idle transfer periods.
Set to 0 to disable TCP Keep Alive.Blank the display field to restore the default.
The TCP Keep Alive Interval timer specifies how often to probe the remote host, after the initial probe, in order to keep the TCP connection up during idle transfer periods.
Blank the display field to restore the default.
The TCP Keep Alive Probes specifies how many TCP Keep Alive probes (after the TCP Initial Keep Alive probe) to send before closing the connection if no response is received.
Valid values are between 1 and 16.
Blank the display field to restore the default.
The TCP User Timeout specifies how long transmitted data may remain unacknowledged before the connection is forcibly closed.
Enter 0 to disable.
Blank the display field to restore the default.
There are two Advanced Encryption Standard (AES) Encryption Keys used for Connect Mode Tunneling. One Key is used for encrypting outgoing data and the other Key is used for decrypting incoming data.
These AES Keys are a fixed 16, 24 or 32 bytes in length. Each key can be entered in Text or Hexadecimal form. Keys are stored and exchanged in Hexadecimal form only.
Text form is a simple string of up to 32 ASCII characters.
The Hexadecimal form takes up to 32 byte specifications
separated by spaces. A byte specification comprises two nibble
specifications with no intervening space. A nibble specification
is a single digit from 0 to 9 or from "a" to "f" (representing
10 through 15).
Example Hexadecimal key:
12 34 56 78 9a bc de f0 01 02 03 04 05 06 07 08
To remove a key, delete <Configured> in the display.
Note that the Keys are shared secret keys so they must be known by both sides of the connection and kept secret.
This device also supports SSH using AES Encryption as an alternative to secure tunneling. It is recommended that SSH be used because it does not require configuring shared secret keys and is a more secure standards based protocol.
The Initial Send data will be sent out the network upon connection establishment before any data from the Line. It may contain one or more Directives of the form %<char>.
The Initial Send string can be entered in Text or Binary
form. The Binary form allows square
braces [ ]
to enclose one or more character designations separated by
commas. Use straight decimal numbers up to 255 or hexadecimal numbers prefixed
with 0x up to 0xFF within the square braces.
To specify an open brace in binary mode, use two in a row. Example (in
Binary mode): AB[255,0xFF]C[[D]
Results in a string containing
binary values where the dots appear: AB··C[D]
Directives
%i | local IP address |
%m | MAC address |
%n | network interface name |
%p | local port |
%s | serial number |
%% | % |
Host Mode controls how multiple hosts shall be used in Connect Mode.
With Sequential selected, when it is time for the tunnel to connect, it will start with host 1 and attempt each host in sequence until a connection is accepted.
With Simultaneous selected, when it is time for the tunnel to connect, it will connect to all of the hosts that accept a connection.
The Reconnect Time specifies how long to wait in milliseconds before trying to reconnect to the remote host after a previous attempt failed or the connection was closed.
Blank the display field to restore the default.
Flush Serial applies at the time when a connection is established to the network.
If Enabled, any buffered characters from the Serial Line will be discarded when a connection is established.
If Disabled, any characters received on the Serial Line will be buffered and sent after a connection is established.
Block Serial may be enabled for debugging purposes.
If Enabled, incoming characters from the Serial Line will NOT be forwarded to the network. Instead, they will be buffered and will eventually flow off the Serial Line if hardware or software flow control is configured.
If Disabled (the normal setting), incoming characters from the Serial Line are sent on into the network. Any buffered characters are sent first.
Block Network may be enabled for debugging purposes.
If Enabled, incoming characters from the network will NOT be forwarded to the Serial Line. Instead, they will be buffered and will eventually flow off the network side.
If Disabled (the normal setting), incoming characters from the network are sent on into the Serial Line. Any buffered characters are sent first.
Email on Connect comes into play when a connect mode tunnel is established. If an Email profile number has been selected, an email notification based on that profile will then be sent.
Email on Disconnect comes into play when a connect mode tunnel is disconnected. If an Email profile number has been selected, an email notification based on that profile will then be sent.
The CP Output Group identifies a CP Group whose value should change when a connection is established and dropped.
Connection Value specifies the value to set the CP Group to when a connection is established.
Disconnection Value specifies the value to set the CP Group to when the connection is closed.
To display "Connection Value" and "Disconnection Value", first enter a "CP Output Group", then click outside that field.