Configuring Napt; Configuring Static Ip Routing; Configuring Rip - Patton electronics SmartNode Series Software Configuration Manual

9 • IP context overview SmartWare Software Configuration Guide
vides higher-layer protocol and service information, such as layer 3 addressing. Hence interfaces are configured
as part of IP context and represent logical entities that are only usable if a physical port is bound to them.
An interface name can be any arbitrary string, but for ease of identification self-explanatory names should be
used which depict the use of the interface. An example is using names like "lan" for an IP interface that con-
nects to the LAN and "wan" for an interface that connects to the access network or WAN. Avoid names that
represent the nature of the underlying physical port for logical interfaces, like "eth0" or "serial0", to represent
Ethernet port 0 or serial port 0, since IP interfaces are not strictly bound to a certain physical port. During the
operation of a SmartNode it is possible to move an IP interface to another physical port, e.g. from an Ethernet
to a serial port. For that reason it would be more than misleading, if an interface holds a name like "eth0", but
actuality is assigned to a serial port. Therefore it is in your interest to decouple a logical interface from a physi-
cal port, by giving names to interfaces that describe their usage and not the physical constitution.
As for any IP interface several IP related configuration parameters are necessary to define the behavior of such
an interface. The most obvious parameters are the IP address and an IP net mask that belongs to it.
For information and examples on how to create and configure an IP interface refer to chapter 10, "IP interface
configuration" on page 109.
Configuring NAPT
Network Address Port Translation (NAPT), which is an extension to NAT, uses TCP/UDP ports in addition to
network addresses (IP addresses) to map multiple private network addresses to a single outside address. There-
fore NAPT allows small offices to save money by requiring only one official outside IP address to connect sev-
eral hosts via a SmartNode to the access network. Moreover NAPT provides additional security, because the IP
addresses of hosts attached via the SmartNode are made invisible to the outside world. Configuring NAPT is
done by creating a profile that is afterwards used on an explicit IP interface. In the terminology of SmartWare
an IP interface uses a NAPT profile, as shown in figure 24 on page 103.
For information and examples on how to configure Network Address Port Translation (NAPT) refer to
chapter 11, "NAT/NAPT configuration" on page 119.
Configuring Static IP Routing
SmartWare allows defining static routing entries, which are table mappings established by the network admin-
istrator prior to the beginning of routing. These mappings do not change unless the network administrator
alters them. Algorithms that use static routes are simple to design and work well in environments in which net-
work traffic is relatively predictable and where network design is relatively simple.
For information and examples on how to configure static IP routing refer to chapter 15, "Basic IP routing con-
figuration" on page 177.
Configuring RIP
The Routing Information Protocol (RIP) is a distance-vector protocol that uses hop count as its metric. RIP is
widely used for routing traffic in the global Internet and is an interior gateway protocol (IGP), which means
that it performs routing within a single autonomous system.
RIP sends routing-update messages at regular intervals and also when the network topology changes. When a
router receives a routing update that includes changes to an entry, it updates its routing table to reflect the new
route. The metric value for the path is increased by one, and the sender is indicated as the next hop. RIP rout-
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Configuring NAPT