Chapter 4 - RouteFinder Software
MTASR3
33
The IP Port Setup Advanced tab enables you to set up various configuration options for the IP
routing protocol. The options that you select here apply to all ports on which IP routing takes place.
In most cases, you should not have to change any of the timers (i.e., default TTL, reassembly
timeout, RIP response time and RIP route aging time). The DNS Resolver is supplied for remote
Telnet clients when the router is configured for remote access and the terminal server application is
enabled.
The Routing option is normally checked; however, if you do not wish to have IP packets routed, then
uncheck this item. If IP routing is disabled and bridging is enabled, IP packets are bridged; i.e., IP
packets are transferred.
The RIP option enables RIP based routing. RIP (Routing Information Protocol) is a protocol used
among routers to exchange routing table information. RIP is the most common protocol used in both
IP and IPX networks. It is also used internally by client workstations in IPX networks to obtain routes
(shortest, or otherwise) to any distant network. RIP based routing should normally be enabled. It can
be disabled, however, if you are using WAN links in Dial on Demand mode. For DOD links, disabling
RIP will reduce traffic on the link as it will also disable periodic RIP broadcasts. RIP routing on a given
port will be automatically turned off when Dial on Demand is enabled on the PPP Port Setup tab for
the WAN port.
The Dynamic Host Configuration Protocol (DHCP) group enables you to set up the WAN ports as
client-only. Then, a PPP client connected to the WAN port will be on the same IP network as the LAN
port of the RouteFinder. This feature can save some extra IP addresses that otherwise would have
been taken up by the WAN port. Enabling the Client option allows the RouteFinder to dynamically get
an IP address for a PPP client coming up on one of its “Client-only” WAN ports. When this option is
enabled, there must be a DHCP server or a DHCP relay agent on the connected LAN in order for the
RouteFinder to acquire an appropriate IP address.
This option applies only to Client-only WAN ports.
If there is no DHCP server on the LAN segment of the RouteFinder, the Relay Agent option must be
enabled so the RouteFinder can relay the DHCP packets between clients on the directly connected
networks ( i.e., clients on the LAN and the PPP clients that are calling-in on client-only WAN ports)
and the server. If the Relay Agent option is enabled, the IP address of the DHCP server (dotted
decimal format) must be entered in the Server Address field.
The RouteFinder supports Domain Name System (DNS) for the terminal server application. This is a
built-in Telnet client that can connect a call coming in on a WAN port from a Telnet host. When a user
dials into the system to get connected to a Telnet server, the RouteFinder will prompt for a Telnet host
address. The user can then either type in the dotted decimal IP address or the domain name of the
host.
The Domain Name System (DNS) group includes a check box where you can enable DNS
Resolver. It also has text boxes where you can enter (in dotted decimal format) the IP addresses of
the local DNS server and a “Root” DNS server to be used should the local DNS server fail to
respond.
The Default TTL text box defines the IP Time-To-Live parameter that sets the maximum number of
hops a frame may travel before being dropped. This is used to limit errant frames such as those that
may arise under circularly defined networks. Recommended value is decimal 255.
The RIP Response Time text box defines the time interval between periodic RIP broadcasts.
Regular RIP broadcasts are required to keep the routing tables of all routers in the internetwork
consistent. Increasing the frequency of these broadcasts may consume precious bandwidth that
could have been used for transfer of other regular packets and has a recommended value of 30
seconds.
The Reassembly Timeout text box defines the amount of time the IP routing software will wait for all
the fragments of an IP datagram to arrive before discarding the partially reassembled datagram and
has a recommended value of 30 seconds.
