TINA Tunnel Settings

The tunnel name. You can enter a maximum of 64 characters.

Disabled

To manually disable the tunnel, select this check box.

The transport type for the tunnel. You can select one of the following options:

• UDP – The tunnel uses UDP port 691 to communicate. This connection type is suited best for response-optimized tunnels. It allows fast transport and generates the least overhead.
• TCP – The tunnel uses TCP connection on port 691 or 443 (for HTTP proxies). This mode is required for connection over SOCKS4 or HTTP proxies. It is useful for unreliable lines where packet loss is common.
• UDP&TCP – The tunnel uses TCP and UDP connections. The tunnel engine uses the TCP connection for UDP requests and the UDP connection for TCP requests and ICMP-based applications.

• ESP – The tunnel uses ESP (IP protocol 50) to communicate. This connection type is best suited for performance-optimized tunnels. This option is useful for a private link such as MPLS, or when ESP is not blocked by NAT.

  • Do not select ESP if there are filtering or NAT interfaces in between.
  • Some routers, especially DSL routers for home accounts and cable modems, block ESP traffic. In this case, select TCP or UDP.

• Routing – Use this option with Traffic Intelligence. It disables data payload encryption within the tunnel and should only be used for uncritical bulk traffic.

  Unencrypted data.

  With this option, you can also specify the next hop address for the routed data packets when configuring the TI traffic transport classification.

The data encryption algorithm. You can select one of the following options:

• AES | AES256 – The Advanced Encryption Standard (default). AES works with 128-bit key length and AES256 works with 256-bit long keys. With AES 256, the security of the encrypted data is increased, but more CPU capacity is required. Only use AES256 when required. Represents a very good compromise between key length and encryption speed. AES encryption speed can also be improved with hardware acceleration. (Recommended.)

• 3DES – Further developed DES encryption. Three keys each having a 56-bit length are used sequentially, providing a key length of 168-bit. (Not recommended.)

  Try to avoid using 3DES because this algorithm works very slowly and only offers acceptable performance with the help of special hardware acceleration cards.

• CAST – Algorithm similar to DES with a key length of 128-bit.
• Blowfish – Works with a variable key length up to 128-bit.
• DES – Digital Encryption Standard. Because DES is only capable of a 56-bit key length, it cannot be considered safe any longer. (Not recommended.)
• Null – No encryption.

The hashing algorithm for the VPN tunnel. You can select one of the following options:

• MD5 – Message Digest 5. Hash length is 128-bit. (Not recommended. High performance, but theoretically vulnerable.)
• SHA – Secure Hash Algorithm. Hash length is 160-bit. (Not recommended. High performance, but theoretically vulnerable.)
• NOHASH – Use NOHASH for systems with hardware encryption support because it allows for hardware-accelerated high encryption performance on these systems.
• RIPEMD160 – RACE Integrity Primitives Evaluation Message Digest. Hash length is 160-bit. (Highly recommended.)
• SHA256 – Secure Hash Algorithm. Hash length is 256-bit. (Highly recommended.)
• SHA512 – Secure Hash Algorithm. Hash length is 512-bit.
• GCM – Galois/Counter Mode (GCM). Hash length is 128-bit. Provides assurance of confidential data authenticity up to about 64 GB per invocation using a universal hash function defined over a binary Galois field.

TI Classification

The VPN transport classification for this tunnel. The first VPN tunnel is always classified as bulk-0. For more information, see Traffic Intelligence.

• Bulk
• Quality
• Fallback

Specifies if HW acceleration or CPU acceleration should be used. You can select one of the following options:

• Use Acceleration Card – If a crypto accelerator hardware board is in use, select this option.
• Use CPU – Use CPU acceleration.

The period of time after which the re-keying process is started. You can select 5, 10 (default), 30, or 60 minutes.

The key traffic limit. You can select No Limit, 1 GB, 500 MB, 100 MB, 50 MB, 10 MB (default), 5 MB, or 1 MB.

The length of time in which tunnel probes must be correctly answered before the tunnel is terminated. If, for some reason, the enveloping connection breaks down, the tunnel must be re-initialized. This is extremely important in setups with redundant possibilities to build the enveloping connection. You can select 3 secs, 10 secs, 20 secs (default), 30 secs, or 60 secs.

From this list, you can select one of the following options to specify if the local network is active or passive:

• Active – An active VPN server accepts tunnel requests and initiates the tunnel connection. When the tunnel is down for a defined time, it cleans its state to accept retries from its partner. Furthermore, it tries to initiate the connection by itself.
• Passive – A passive VPN server does not build up the tunnel. It merely accepts requests from its partner. If the tunnel is down for a defined time, it cleans its state to accept retries from its partner.
• OnDemand – Use this option with Traffic Intelligence. The VPN server actively builds up a connection and terminates it during the time-outs specified by the On Demand Transport Timeout setting from the TI - VPN Envelope Policy tab.

• First Server IP – The first server IP address is used.
• Second Server IP – The second server IP address is used.
• Dynamic (via routing) – The IP address is specified by the routing table.
• Explicit (ordered list) – To explicitly specify the IP addresses or devices used, select this option. This option is important to ensure redundancy on the active side of the tunnel.

• Direct (no Proxy) – The standard connection.
• HTTP Proxy – An HTTP proxy server with optional user/password authentication is used.
• Socks 4 Proxy – A SOCKS4 server is used.
• Socks 5 Proxy – A SOCKS5 server is used.

The IP addresses, hostname, or, if the call direction is passive, enter the subnet of the VPN partner.

When using a hostname as the destination, the VPN service caches the resolved IP address for the TTL of the DNS record. This may result in problems with DynDNS domains using a long TTL. For more information on how to clear the cache manually, see Clearing the DNS Cache of the VPN Service below.