DHCP

Specify the "dhcp" option on each interface to be served by your server in the /etc/shorewall/interfaces file.

When starting "dhcpd", you need to list those interfaces on the run line. On a RedHat system, this is done by modifying /etc/sysconfig/dhcpd.

Specify the "dhcp" option for this interface in the /etc/shorewall/interfaces file.

If you know that the dynamic address is always going to be in the same subnet, you can specify the subnet address in the interface's entry in the /etc/shorewall/interfaces file.

If you don't know the subnet address in advance, you should specify "detect" for the interface's subnet address in the /etc/shorewall/interfaces file and start Shorewall after the interface has started.

In the event that the subnet address might change while Shorewall is started, you need to arrange for a "shorewall refresh" command to be executed when a new dynamic IP address gets assigned to the interface. Check your DHCP client's documentation.