Reference Guide

IPv4 Routing | 417

IPv4 Routing

IPv4 Routing is supported on platforms: e c s z

FTOS supports various IP addressing features. This chapter explains the basics of Domain Name Service

(DNS), Address Resolution Protocol (ARP), and routing principles and their implementation in FTOS.

• IP Addresses

• Directed Broadcast

• Resolution of Host Names

• ARP

• ICMP

• UDP Helper

Table 20-1 lists the defaults for the IP addressing features described in this chapter.

IP Addresses

FTOS supports IP version 4, as described in RFC 791. It also supports classful routing and Variable Length

Subnet Masks (VLSM). With VLSM one network can be can configured with different masks.

Supernetting, which increases the number of subnets, is also supported. Subnetting is when a mask is

added to the IP address to separate the network and host portions of the IP address.

Table 20-1. IP Defaults

IP Feature Default

DNS Disabled

Directed Broadcast Disabled

Proxy ARP Enabled

ICMP Unreachable Disabled

ICMP Redirect Disabled