Motorola 3347 User Manual

Page 86

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.

Select either User Conﬁgured PC or an IP address displayed in the selec-
tion window (these are the IP addresses currently being served to com-
puters on your LAN.)

If you select “User Configured PC”, you must then configure a local PC to have the pub-
lic WAN IP address.

Click

Enable

You will be reminded to restar t the Router.

Click the

Restart Router

link and conﬁrm the restart when prompted.

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 Router and the passthrough host will use the same IP address, new ses-
sions that conflict with existing sessions will be rejected by the Router. For example, sup-
pose you are a teleworker using an IPSec tunnel from the Router 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 indistinguishable – will fail.