Prepare your CCNA exams with this CCNA Portable Command Guide book. This book will help you memorize commands and concepts as you work to pass the CCNA exam (INTRO 640-821, ICND 640-811, or CCNA 640-801). The guide summarizes all CCNA certification-level Cisco IOS® Software commands, keywords, command arguments, and associated prompts, providing you with tips and examples of how to apply the commands to real-world scenarios. Configuration examples throughout the book provide you with a better understanding of how these commands are used in simple network designs.
NAT and PAT main features:
NAT (Network Address Translation) can be used for a variety of purposes and can be either dynamically or statically assigned. Static NAT is designed to allow one-to-one mapping of local and global addresses. This is particularly useful for hosts which must have a consistent address that is accessible from the Internet. These internal hosts may be enterprise servers or networking devices.
Objective
In this lab, configure a default route and use RIP to propagate this default information to other routers. When this configuration has reached convergence, migrate the network from RIP to IGRP and configure default routing to work with that protocol as well.
Introduction
Default routes are used to direct packets addressed to networks not explicitly listed in the routing table.
Default routes are invaluable in topologies where learning all the more specific networks is not desirable, as in case of stub networks, or not feasible due to limited system resources such as memory and processing power.
This document explains how to configure a default route, or gateway of last resort. These IP commands are used:
- ip default−gateway
- ip default−network
- and ip route 0.0.0.0 0.0.0.0
Dynamic Host Configuration Protocol (DHCP) Explanation for your CCNA Exams reference…
DHCP Description:
- DHCP works in a client/server mode. DHCP enables DHCP clients on an IP network to obtain their configurations from a DHCP server.
- DHCP is not intended for configuring routers, switches, and servers. These type of hosts need to have static IP addresses.
- DHCP works by providing a process for a server to allocate IP information to clients. Clients lease the information from the server for an administratively defined period. When the lease expires the client must ask for another address, although the client is typically reassigned the same address. Administrators typically prefer a network server to offer DHCP services because these solutions are scalable and relatively easy to manage. Cisco routers can use a Cisco IOS feature set, Easy IP, to offer an optional, full-featured DHCP server.
- Administrators set up DHCP servers to assign addresses from predefined pools. DHCP servers can also offer other information, such as DNS server addresses, WINS server addresses, and domain names. Most DHCP servers also allow the administrator to define specifically what client MAC addresses can be serviced and automatically assign them the same IP address each time. DHCP uses User Datagram Protocol (UDP) as its transport protocol. The client sends messages to the server on port 67. The server sends messages to the client on port 68.
