The Routers Configuration

Table of contents:

The Router s Configuration

Every router has two different configurations to consider:


Running configuration

The router's active configuration, which is stored in the router's RAM. Every configuration command you give is stored in the running configuration . If you reboot your router, this configuration is lost. If you make changes that you want to save, you must copy the running configuration to a safe location, such as a network server, or save it as the router's startup configuration .


Startup configuration

The configuration that is loaded when the router boots. This configuration is stored in the router's nonvolatile memory (NVRAM) . You cannot edit a startup configuration directly. All commands you enter are stored in the running configuration, which can be copied into the startup configuration.

In other words, when you boot a router, the startup configuration becomes the initial running configuration. As you modify the configuration, the two diverge: the startup configuration remains the same, while the running configuration reflects the changes you have made. If you want to make your changes permanent, you must copy the running configuration to the startup configuration.

The following command copies the router's current running configuration into the startup configuration:

Router#copy running-config startup-config
Building configuration...

Similarly, to save the running configuration on a network server using TFTP, you would give the command:

Router#copy running-config tftp

You'll be prompted for additional information, such as the remote host and the name for the saved file.

The terms "running configuration" and "startup configuration" were added in recent versions of IOS. In earlier versions, you used the command write terminal to display the current router configuration and write memory to store the current configuration. This terminology is outdated; use the copy command.

Getting Started

IOS Images and Configuration Files

Basic Router Configuration

Line Commands

Interface Commands

Networking Technologies

Access Lists

IP Routing Topics

Interior Routing Protocols

Border Gateway Protocol

Quality of Service

Dial-on-Demand Routing

Specialized Networking Topics

Switches and VLANs

Router Security

Troubleshooting and Logging

Quick Reference

Appendix A Network Basics


Cisco IOS in a Nutshell
Cisco IOS in a Nutshell (In a Nutshell (OReilly))
ISBN: 0596008694
EAN: 2147483647
Year: 2006
Pages: 1031
Authors: James Boney © 2008-2020.
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