RUT240 VPN

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GRE Tunnel

GRE (Generic Routing Encapsulation RFC2784) is a solution for tunneling RFC1812 private address-space traffic over an intermediate TCP/IP network such as the Internet. GRE tunneling does not use encryption it simply encapsulates data and sends it over the wide area network (WAN).

In the example network diagram two distant networks LAN1 and LAN2 are connected. To create A GRE tunnel the user must know the following parameters:

Source and destination IP addresses
Tunnel’s local IP address
Distant network’s IP address and Subnet mask

To create a new GRE instance, go to the GRE Tunnel tab, type in a name for your new instance in the text field below the GRE Tunnel tab and press the Add New button next to it. The newly created instance will be disabled and unconfigured. To configure it press the Edit button located next to it. This action will redirect you to the instance’s GRE Tunnel Configuration window.

field name	value	description
Enabled	yes \| no; Default: no	Toggles GRE Tunnel ON or OFF
Remote endpoint IP address	ip; Default: " "	WAN IP address or hostname of the remote GRE Tunnel instance
Remote network	integer [0..32]; Default: " "	LAN IP address of the remote device
Remote network netmask	integer [0..32]; Default: " "	LAN netmask of the remote device
Local tunnel IP	ip; Default: " "	Local virtual IP address. Can’t be in the same subnet as LAN network
MTU	integer [0..255]; Default: 255	Toggles the Path Maximum Transmission Unit Discovery (PMTUD) status on this tunnel ON or OFF
TTL	integer [0..255]; Default: 255	Fixed time-to-live (TTL) value on tunneled packets. The 0 is a special value meaning that packets inherit the TTL value
PMTUD	yes \| no; Default: no	Toggles the Path Maximum Transmission Unit Discovery (PMTUD) status on this tunnel ON or OFF
Redirect LAN to GRE	yes \| no; Default: no	Redirects LAN traffic to the GRE interface
Enable Keep alive	yes \| no; Default: no	Gives the ability for one side to originate and receive keep alive packets to and from a remote router
Keep Alive host	host \| ip; Default: " "	Keep Alive IP address to send pings to. Preferably this should be an IP address which belongs to the LAN network on the remote device
Keep alive interval	integer [0..255]; Default: " "	Frequency at which ICMP packets are sent by the Keep Alive function (in seconds)

To find a more in-depth GRE Tunnel configuration example, visit this page

PPTP

Point-to-Point Tunneling Protocol (PPTP) is a protocol (set of communication rules) that allows corporations to extend their own corporate network through private "tunnels" over the public Internet. Effectively, a corporation uses a wide-area network as a single large local area network. A company no longer needs to lease its own lines for wide-area communication but can securely use the public networks.

For a more in-depth configuration example, visit the PPTP configuration examples page.

PPTP Client

To create a new PPTP instance, go to the PPTP tab, select the Role (server or client) of your instance, type in a name in the New configuration name field and press the Add button next to it. The newly created instance will be disabled and unconfigured. To configure it click the Edit button located next to it. This action will redirect you to the instance’s PPTP Configuration window.

field name	value	description
Enable	yes \| no; Default: no	Toggles PPTP Client ON or OFF
Use as default gateway	yes \| no; Default: no	Use this PPTP instance as default gateway
Client to client	yes \| no; Default: no	Toggles client to client on the PPTP tunnel ON or OFF
Server	host \| ip; Default: " "	PPTP server's IP address or hostname
Username	string; Default: " "	User name for authorization with the server
Password	string; Default: " "	Password used for authorization with the server

PPTP Server

field name	value	description
Enable	yes \| no; Default: no	Toggles PPTP Server ON or OFF
Local IP	ip; Default: 192.168.0.1	Virtual IP Address of this PPTP server
Remote IP range begin	ip; Default: 192.168.0.20	Client IP address leases beginning
Remote IP range end	ip; Default: 192.168.0.30	Client IP address leases end
User name	string; Default: youruser	Client's user name used for authentication with this server
Password	string; Default: yourpass	Client's password used for authentication with this server
PPTP Client's IP	ip; Default: " "	Client’s IP address. Leave empty to assign a random IP from the IP range specified above

L2TP

In computer networking, Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs). It is more secure than PPTP but, because it encapsulates the transferred date twice, but it is slower and uses more CPU power.

For a more in-depth configuration example, visit the L2TP configuration examples page.

L2TP Client

To create a new L2TP instance, go to the L2TP tab, select the Role (server or client) of your instance, type in a name in the New configuration name field and press the Add button next to it. The newly created instance will be disabled and unconfigured. To configure it press the Edit button located next to it. This action will redirect you to the instance’s L2TP Configuration window.

field name	value	description
Enable	yes \| no; Default: no	Toggles L2TP Client ON or OFF
Server	host \| ip; Default: " "	L2TP server's remote IP address or hostname
Username	string; Default: " "	User name used to authenticate you to the L2TP server
Password	string; Default: " "	Password used to authenticate you to the server

L2TP Server

field name	value	description
Enable	yes \| no; Default: no	Toggles L2TP Server ON or OFF
Local IP	ip; Default: 192.168.0.1	Virtual IP Address of this L2TP server
Remote IP range begin	ip; Default: 192.168.0.20	Client IP address leases beginning
Remote IP range end	ip; Default: 192.168.0.30	Client IP address leases end
User name	string; Default: user	Client's user name used for authentication with this server
Password	string; Default: pass	Client's password used for authentication with this server

Stunnel

Stunnel is an open-source multi-platform software application used to provide a TLS/SSL tunneling service for already existing clients and servers. Below is an overview of the Stunnel application and its WebUI configuration section implemented on RUTxxx routers. For in-depth examples please visit Stunnel page.

Here is an approximate visual representation of Stunnel connection:

Upon creation, Stunnel configuration will be empty. User is expected to define their own configuration using the created configuration template. Stunnel provided encryption and connection will only work with properly configured Stunnel server(s) and client(s).

Duplicate configuration names are not allowed.

Stunnel configuration list window is located at Services → VPN → Stunnel:

Services menu, VPN section:

Stunnel tab:

To create a new configuration, enter the desired name in field below all configuration list entries and click button Add:

Once you’ve added a new Stunnel configuration, it is automatically saved - no need to press the Save button.

By default the configuration will be disabled and unconfigured. You can change the configuration by clicking the Edit button and delete the configuration by clicking the Delete button.

To establish an Stunnel connection you must have configured and enabled Stunnel client and server instances on either same or different routers.

Stunnel Configuration

Default Stunnel configuration:

Stunnel configuration field explanation table:

Field Name	Value	Description
Enabled	yes \| no; Default: no	Enables the Stunnel configuration.
Operating Mode	Client \| Server; Default: ""	Specifies whether this configuration will be used for Stunnel client or server.
Listen IP	ip \| host; Default: ""	OPTIONAL Specifies which IP address or host should Stunnel listen to. If left empty, defaults to localhost.
Listen Port	port (integer [0..65535]); Default: ""	Specifies TCP port which Stunnel should listen to. Port cannot be taken by another service!
Connect IP's	[host:]port; Default: ""	Uses the standard host:port convetion (e.g. 127.0.0.1:6001; localhost:6001). Host part can be emmited - empty host part defaults to localhost. Must contain at least one item. If multiple options are specified, remote address is chosen using a round-robin algorithm.
TLS Cipher	None \| Secure \| Custom	Select permitted TLS ciphers (TLSv1.2 and below). If custom is selected, a new field appears to enter custom ciphers.
Allowed TLS Ciphers	Cipher[:Cipher]..; Default: ""	Only appears if a Custom TLS Cipher is selected A colon-delimited TLS cipher list (e.g. DES-CBC3-SHA:IDEA-CBC-MD5)
Application Protocol	Not specified \| Connect \| SMTP; Default: Not specified	CLIENT SIDE ONLY This option enables initial, protocol-specific negotiation of the TLS encryption. The protocol option should not be used with TLS encryption on a separate port. If Connect or SMTP is selected, more customization fields appear.
Protocol Authentication	Connect: Basic \| NTLM; Default: Basic SMTP: Plain \| Login; Default: Plain	CLIENT SIDE ONLY Options depend on the selected protocol Authentication type for the protocol negotiations.
Protocol Domain	domain (text); Default: ""	CLIENT SIDE ONLY Only appears if a Connect protocol is selected Domain for the protocol negotiations.
Protocol Host	host:port; Default: ""	CLIENT SIDE ONLY Only appears if a Connect protocol is selected Destination address for the protocol negotiations. Specifies the final TLS server to be connected to by the proxy, and not the proxy server directly connected by Stunnel. The proxy server should be specified with the connect option.
Protocol Username	username (text); Default: ""	CLIENT SIDE ONLY Only appears if a protocol is selected Username for the protocol negotiations.
Protocol Password	password (text); Default: ""	CLIENT SIDE ONLY Only appears if a protocol is selected Password for the protocol negotiations.
Verification	None \| Verify Chain \| Verify Peer; Default: None	Verification type. Verify Chain verifies connections against a Certificate Authority (CA) file, while Verify Peer verifies connections against a list of approved certificates.
Verification file	file; Default: ""	Only appears if a verification type is selected File which is used to verify peer(s) or a peer chain. A different type of file is expected depending on the verification type selected: Verify Chain: Expects a CA (Certificate Authority) file. Verify Peer: Expects a file with one (or more, concatenated) peer certificate(s).
Certificate File	file; Default: ""	Mandatory for a server configuration. Optional for a client configuration The parameter specifies the file containing certificates used by stunnel to authenticate itself against the remote client or server. The file should contain the whole certificate chain starting from the actual server/client certificate, and ending with the self-signed root CA certificate. Can be a certificate only, or both certificate and private key concatenated into a single file.
Private Key	file; Default: Certificate File	Can be skipped if the Certificate File is appended with the private key Must be uploaded if the Certificate File does not contain the private key A private key, required to authenticate the certificate owner.

After setting the parameters, click the Save button; otherwise, changes will not be saved. Some parameters will be shown in the configuration list table.

Stunnel Global Configuration

Default Stunnel global configuration:

Stunnel global configuration field explanation table:

Field Name	Value	Description
Enabled	yes \| no; Default: no	Enables/activates all the enabled Stunnel configurations.
Debug Level	integer [0..7]; Default: 5	Debugging level. Level is one of the syslog level names or numbers emerg (0), alert (1), crit (2), err (3), warning (4), notice (5), info (6), or debug (7). All logs for the specified level and all levels numerically less than it will be shown. Use 7 for greatest debugging output.
Use alternative config	yes \| no; Default: no	Enable alternative configuration option (Config upload). Be aware that when using alternative configuration, all configurations in Stunnel Configuration section will be skipped.
Upload alternative config	file; Default: ""	Only appears if the "Use alternative config" is enabled Upload the alternative Stunnel configuration file.

IMPORTANT:

The router can have multiple configurations set up and enabled at the same time. Note that if at least one configuration is not set correctly, none of them will be enabled, despite the "Enabled" flag being marked.

Also, you must mark the global "Enabled" flag to actually enable all the individually marked configurations.