Tinc is a newer VPN technology that allows you to create partial/full mesh VPN connections without having to define every endpoint, as you'd have to with other VPN protocols. A minimum amount of configuration is still needed for each site. However, it's the quickest way to develop a mesh VPN between network sites.

The Tinc Daemon menu is divided into tabbed sections, including Tinc Configuration, and (VPN) Hosts.

Start with WAN: Enabling this will cause the Tinc daemon to start as part of the wanup (WAN interface initialization) process.

Interface type: TUN/TAP: Here, you specify the communication protocol used within your VPN. TUN is routed, and runs at the network (IP) layer. TAP is switched, and runs at the datalink layer. Generally, you should choose TUN. For more information on these protocols, see the “Interface Type” section of the OpenVPN Server wiki page.

VPN Netmask: Here, specify the (sub)netmask to be used for intra-site communications.

Host Name: This is the unique identifier of the OpenVPN device. This is NOT the same as the device's DHCP/DNS Hostnames.

Poll interval: If set greater than zero, a watchdog polls whether Tinc is running every n minutes to verify that it has not crashed. If it finds that Tinc is not running, it will restart the Tinc service. If set to zero, the watchdog is disabled.

Ed25519 Private Key: In this field, enter your private Ed25519 encryption key. This key is needed for the encryption process.

RSA Private Key: * Here, enter the private RSA key. RSA encryption uses much more CPU power than the Ed25519 protocol.
The RSA key is optional and is needed only for communication with hosts using Tinc version 1.0 or lower.

Custom: This field allows you to specify any custom Tinc daemon parameters you might want.

Most of the hosts on your network should be defined on this page. Tinc doesn't need all hosts to be defined. It can use a relay to reach secondary hosts if the end devices can't (yet) communicate. Hosts may not be able to communicate for various reasons, including the presence of NAT devices between them.

However, you do need to define “yourself” on each Tinc device.

ConnectTo: This flag can be set “On” or left blank. This tells the local Tinc daemon to try connecting directly to another host (without using a relay).

Name: As on the Config tab, this is the unique Tinc identifier defined in the Host Name field.

Address: This is used only when direct communication is possible. It defines the IP address (or FQDN) where the host can be found. This means without a relay.

Port: If left blank, this configures the default setting (TCP/UDP, port 655). You might need to tune this for network devices without root/Administrator privileges (but not FreshTomato).

Compression: In some cases, compression may increase VPN speeds. The default of “0” (disabled) can be adjusted as high as “11”. All nodes must be configured with the same setting. Since most VPN traffic is already compressed at the application layer, think carefully whether you need this enabled. Enabling compression adds extra workload to the CPU, and may not increase throughput.

Subnet: This defines the primary subnet reachable via the host being defined. It's published to the tinc peers so they know which peer hosts the subnet.

Ed25519 Public Key: Here is where you enter your Ed25519 encryption Public Key.

RSA Public Key: * If you're using RSA encryption, you must define each host's public key here. RSA is optional in Tinc versions 1.0 and later.

You must provide minimal information for every host defined before you can click OK and go to the next row. Clicking OK does not save settings. Only after you've defined all hosts, clicked “OK” for each, and clicked “Save” at the bottom. will all host settings be saved.

Custom: In this field, you can define custom settings for each host.

For example, if a host communicates with with another subnet, you could add:

Subnet = 10.10.8.0/24 .

You must ensure these settings are consistent with the host IP/subnet + config-page “netmask” setting.