40
MultiFRAD 3000-Series User Guide
Changing IP Parameters
The IP Setup dialog box allows you change the IP routing capabilities, add or delete logical WANs,
enable the DHCP relay agent, assign DNS address, and define default and static routes. The initial
routing capabilities were established during the software installation. You can change IP routing
parameters by clicking on the Advanced tab and changing, for example, the RIP Response Time or
RIP Route Aging Time. The WAN tab allows you to change the WAN port IP address, the remote
address, and if logical WAN ports are being added for frame relay, you can add them by clicking on
the Add button.
The Ethernet IP Setup dialog box displays the parameters for your Ethernet port with the IP Address
established during the initial loading of the software. The Ethernet, and WAN tabs allow you to
configure parameters for the selected port. Although these tabs all contain the same option groups,
certain parameters may be inactive or disabled (grayed-out) when they do not apply to the selected
port.
The net mask specifies the network or subnet portion of an IP address. The net mask is a 32-bit
value presented in a dotted decimal notation.
The Frame Type option defines the MAC layer frame encapsulation to be used for IP transmissions
from the specified port. The Ethernet port supports Type II and SNAP frames, but the WAN ports
support only Type II frames.
In the Support group, ICMP Redirect defines if the specified port is permitted to issue an ICMP
Redirect message to the source IP address. The most likely cause of this message is the delivery of
a datagram to a MultiFRAD that is not on the forwarding path to the destination address. This is
often due to a wrong configuration of the IP client sending the datagram. The packet causing the
ICMP Redirect message to be transmitted is forwarded to the appropriate MultiFRAD.
ICMP Mask Reply enables support for nodes on the connected networks to learn their subnet
masks.
RIP enables RIP based routing on the specified port, and is normally enabled. However, RIP can be
disabled if you are using the WAN link in Dial-on-Demand mode. Disabling RIP will reduce traffic on
the link as this will also disable periodic RIP broadcasts. RIP routing on the port will be automatically
turned off when Dial-on-Demand is enabled in PPP port setup.
Finally, the RIP Poisoned Reverse option defines if Poisoned Reverse RIP messages are supported
on the specified port. Generation and processing of poisoned routes (RIP entries with their
respective metric set to 16 (defined as infinity)) is enabled/disabled by this parameter. Poisoned
reverse is a method used by RIP to improve the rate of convergence of the routing tables of
interconnected IP MultiFRAD. MultiFRADs supporting poisoned reverse that receive such RIPs
ignore the entries set to 16 and thus prevent the propagation of unnecessary (and often incorrect