FireBrick FB6602, Руководство пользователя

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Interfaces and Subnets
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To create or edit subnets, select the Interface category in the top-level icons, then click Edit next to the
appropriate interface - under the section headed "IP subnet on the interface", you will see the list of existing
subnet
child objects (if any), and an "Add" link.
Note
In a factory reset configuration, there are two temporary subnets defined on the "LAN" interface :
2001:DB8::1/64
and
10.0.0.1/24
. These subnet definitions provide a default IP address that
the FB6000 can initially be accessed on, regardless of whether the FB6000 has been able to obtain an
address from an existing DHCP server on the network. Once you have added new subnets to suit your
requirements, and tested that they work as expected, these temporary definitions should be removed.
To create a new subnet, click on the Add link to take you to a new
subnet
object defintion. Tick the
ip
checkbox, and enter the appropriate CIDR notation.
Editing an existing subnet works similarly - click the Edit link next to the subnet you want to modify.
6.3.1.1. Using DHCP to configure a subnet
You can create a subnet that is configured via DHCP by clearing the
ip
checkbox - the absence of an IP address/
prefix specification causes the FB6000 to attempt to obtain an address from a DHCP server (which must be
in the same broadcast domain). It may help to use the Comment field to note that the subnet is configured via
DHCP.
In its simplest form, a DHCP configured subnet is created by the following XML :-
<subnet />
6.3.2. Setting up DHCP server parameters
The FB6000 can act as a DHCP server to dynamically allocate IP addresses to clients. Optionally, the allocation
can be accompanied by information such as a list of DNS resolvers that the client should use.
Since the DHCP behaviour needs to be defined for each interface (specifically, each broadcast domain), the
behaviour is controlled by one or more
dhcp objects, which are children of an interface object.
Address allocations are made from a pool of addresses - the pool is either explicitly defined using the
ip
attribute, or if
ip
is not specified, it consists of all addresses on the interface i.e. from all subnets, but excluding
network or broadcast addresses, or any addresses that the FB6000 has seen ARP responses for (i.e. addresses
already in use, perhaps through a static address configuration on a machine).
The XML below shows an example of an explicitly-specified DHCP pool :-
<interface ...>
...
<dhcp name="LAN"
ip="172.30.16.50-80"
log="default"/>
...
</interface>
Every allocation made by the DHCP server built-in to the FB6000 is stored in non-volatile memory, and as
such will survive power-cycling and/or rebooting. The allocations can be seen using the "DHCP" item in the
"Status" menu, or using the
show dhcp
CLI command.
If a client does not request renewal of the lease before it expires, the allocation entry will show "expired".
Expired entries remain stored, and are used to lease the same IP address again if the same client (as identified