Interface Groups - D-Link DFL-1660 User Manual

3.4.6. Interface Groups

3. Define a route in the main routing table which routes all traffic to remote_net_A on the
GRE_to_A GRE interface. This is not necessary if the option Add route for remote network
is enabled in the Advanced tab, since this will add the route automatically.
4. Create the following rules in the IP rule set that allow traffic to pass through the tunnel:
Name
To_A
From_A
Checking GRE Tunnel Status
IPsec tunnels have a status of being either up or not up. With GRE tunnels in NetDefendOS this
does not really apply. The GRE tunnel is up if it exists in the configuration.
However, we can check on the what is going on with a GRE tunnel. For example, if the tunnel is
called gre_interface then we can use the ifstat CLI command:
gw-world:/> ifstat gre_interface
This will show us what is happening with the tunnel and the ifstat command options can provide
various details.
3.4.6. Interface Groups
Any set of NetDefendOS interfaces can be grouped together into an Interface Group. This then acts
as a single NetDefendOS configuration object which can be used in creating security policies in the
place of a single group. When a group is used, for example, as the source interface in an IP rule ,
any of the interfaces in the group could provide a match for the rule.
A group can consist of ordinary Ethernet interfaces or it could consist of other types such as VLAN
interfaces or VPN Tunnels. Also, the members of a group do not need to be of the same type. A
group might consist, for example, of a combination of two Ethernet interfaces and four VLAN
interfaces.
The Security/Transport Equivalent Option
When creating an interface group, the option Security/Transport Equivalent can be enabled (it is
disabled by default). Enabling the option means that the group can be used as the destination
interface in NetDefendOS rules where connections might need to be moved between two interfaces.
For example, the interface might change with route failover or OSPF.
If a connection is moved from one interface to another within a group and Security/Transport
Equivalent is enabled, NetDefendOS will not check the connection against the NetDefendOS rule
sets with the new interface.
With the option disabled, a connection cannot be moved to another interface in the group and is
instead dropped and must be reopened. This new connection is then checked against the
NetDefendOS rule sets. In some cases, such as an alternative interface that is much slower, it may
not be sensible to allow certain connections over the new interface.
Example 3.17. Creating an Interface Group
Command-Line Interface
Action Src Int
Allow lan
Allow GRE_to_A
126
Src Net Dest Int
lannet GRE_to_A
remote_net_A lan
Chapter 3. Fundamentals
Dest Net Service
remote_net_A all_services
lannet all_services