A restriction – Motorola Netopia 3342N User Manual
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DHCP address ser ving can automatically ser ve the WAN IP address to a LAN computer.
When DHCP is used for addressing the designated passthrough PC, the acquired or configured WAN
address is passed to DHCP, which will dynamically configure a single-ser vable-address subnet, and
reser ve the address for the configured MAC address. This dynamic subnet configuration is based on the
local and remote WAN address and subnet mask. If the WAN inter face does not have a suitable subnet
mask that is usable, for example when using PPP or PPPoE, the DHCP subnet configuration will default
to a class C subnet mask.
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If you want to manually assign the WAN address to a LAN PC, do not check the
DHCP Enable checkbox.
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If you check the
DHCP Enable checkbox, the screen expands.
The
Host Hardware Address field displays. Here you enter the MAC address of the designated IP-
Passthrough computer.
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If this MAC address is not all zeroes, then it will use DHCP to set the LAN host's address to the (config-
ured or acquired) WAN IP address.
The MAC address must be six colon-delimited or dash-delimited sets of hex digits ('0' – 'FF').
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If you leave the MAC address as zeros then the first DHCP client will be assigned the WAN address.
Once configured, the passthrough host's DHCP leases will be shor tened to two minutes. This allows for
timely updates of the host's IP address, which will be a private IP address before the WAN connection is
established. After the WAN connection is established and has an address, the passthrough host can renew
its DHCP address binding to acquire the WAN IP address.
A restriction.
Since both the Gateway and the passthrough host will use the same IP address, new ses-
sions that conflict with existing sessions will be rejected by the Gateway. For example, suppose you are a
teleworker using an IPSec tunnel from the Gateway and from the passthrough host. Both tunnels go to the
same remote endpoint, such as the VPN access concentrator at your employer’s office. In this case, the
first one to star t the IPSec traffic will be allowed; the second one – since, from the WAN, it's indistinguish-
able – will fail.