Cisco Cookbook

Larger Cover

Cisco Cookbook

By Kevin Dooley, Ian Brown

Publisher: O'Reilly Media

Released: July 2003

Pages: 912

While several publishers (including O'Reilly) supply excellent documentation of router features, the trick is knowing when, why, and how to use these features There are often many different ways to solve any given networking problem using Cisco devices, and some solutions are clearly more effective than others. The pressing question for a network engineer is which of the many potential solutions is the most appropriate for a particular situation. Once you have decided to use a particular feature, how should you implement it? Unfortunately, the documentation describing a particular command or feature frequently does very little to answer either of these questions.

Everybody who has worked with Cisco routers for any length of time has had to ask their friends and co-workers for example router configuration files that show how to solve a common problem. A good working configuration example can often save huge amounts of time and frustration when implementing a feature that you've never used before. The Cisco Cookbook gathers hundreds of example router configurations all in one place.

As the name suggests, Cisco Cookbook is organized as a series of recipes. Each recipe begins with a problem statement that describes a common situation that you might face. After each problem statement is a brief solution that shows a sample router configuration or script that you can use to resolve this particular problem. A discussion section then describes the solution, how it works, and when you should or should not use it. The chapters are organized by the feature or protocol discussed. If you are looking for information on a particular feature such as NAT, NTP or SNMP, you can turn to that chapter and find a variety of related recipes. Most chapters list basic problems first, and any unusual or complicated situations last.

The Cisco Cookbook will quickly become your "go to" resource for researching and solving complex router configuration issues, saving you time and making your network more efficient. It covers:

Router Configuration and File Management
Router Management
User Access and Privilege Levels
TACACS+
IP Routing
RIP
EIGRP
OSPF
BGP
Frame Relay
Queueing and Congestion
Tunnels and VPNs
Dial Backup
NTP and Time
DLSw
Router Interfaces and Media
Simple Network Management Protocol
Logging
Access Lists
DHCP
NAT
Hot Standby Router Protocol
IP Multicast

Chapter 1 Router Configuration and File Management
1. Introduction
2. Configuring the Router via TFTP
3. Saving Router Configuration to Server
4. Booting the Router Using a Remote Configuration File
5. Storing Configuration Files Larger than NVRAM
6. Clearing the Startup Configuration
7. Loading a New IOS Image
8. Booting a Different IOS Image
9. Booting Over the Network
10. Copying an IOS Image to a Server
11. Copying an IOS Image Through the Console
12. Deleting Files from Flash
13. Partitioning Flash
14. Using the Router as a TFTP Server
15. Using FTP from the Router
16. Generating Large Numbers of Router Configurations
17. Changing the Configurations of Many Routers at Once
18. Extracting Hardware Inventory Information
19. Backing Up Router Configurations
Chapter 2 Router Management
1. Introduction
2. Creating Command Aliases
3. Managing the Router’s ARP Cache
4. Tuning Router Buffers
5. Using the Cisco Discovery Protocol
6. Disabling the Cisco Discovery Protocol
7. Using the Small Servers
8. Enabling HTTP Access to a Router
9. Using Static Hostname Tables
10. Enabling Domain Name Services
11. Disabling Domain Name Lookups
12. Specifying a Router Reload Time
13. Creating Exception Dump Files
14. Generating a Report of Interface Information
15. Generating a Report of Routing Table Information
16. Generating a Report of ARP Table Information
17. Generating a Server Host Table File
Chapter 3 User Access and Privilege Levels
1. Introduction
2. Setting Up User IDs
3. Encrypting Passwords
4. Using Better Encryption Techniques
5. Removing Passwords from a Router Configuration File
6. Deciphering Cisco’s Weak Password Encryption
7. Displaying Active Users
8. Sending Messages to Other Users
9. Changing the Number of VTYs
10. Changing VTY Timeouts
11. Restricting VTY Access by Protocol
12. Enabling Absolute Timeouts on VTY Lines
13. Implementing Banners
14. Disabling Banners on a Port
15. Disabling Router Lines
16. Reserving a VTY Port for Administrative Access
17. Restricting Inbound Telnet Access
18. Logging Telnet Access
19. Setting the Source Address for Telnet
20. Automating the Login Sequence
21. Using SSH for Secure Access
22. Changing the Privilege Level of IOS Commands
23. Defining Per-User Privileges
24. Defining Per-Port Privileges
Chapter 4 TACACS+
1. Introduction
2. Authenticating Login IDs from a Central System
3. Restricting Command Access
4. Losing Access to the TACACS+ Server
5. Disabling TACACS+ Authentication on a Particular Line
6. Capturing User Keystrokes
7. Logging System Events
8. Setting the IP Source Address for TACACS+ Messages
9. Obtaining Free TACACS+ Server Software
10. Sample Server Configuration Files
Chapter 5 IP Routing
1. Introduction
2. Finding an IP Route
3. Finding Types of IP Routes
4. Converting Different Mask Formats
5. Using Static Routing
6. Floating Static Routes
7. Using Policy-Based Routing to Route Based on Source Address
8. Using Policy-Based Routing to Route Based on Application Type
9. Examining Policy-Based Routing
10. Changing Administrative Distances
11. Routing Over Multiple Paths with Equal Costs
Chapter 6 RIP
1. Introduction
2. Configuring RIP Version 1
3. Filtering Routes with RIP
4. Redistributing Static Routes into RIP
5. Redistributing Routes Using Route Maps
6. Creating a Default Route in RIP
7. Disabling RIP on an Interface
8. Unicast Updates for RIP
9. Applying Offsets to Routes
10. Adjusting Timers
11. Configuring Interpacket Delay
12. Enabling Triggered Updates
13. Increasing the RIP Input Queue
14. Configuring RIP Version 2
15. Enabling RIP Authentication
16. RIP Route Summarization
17. Route Tagging
Chapter 7 EIGRP
1. Introduction
2. Configuring EIGRP
3. Filtering Routes with EIGRP
4. Redistributing Routes into EIGRP
5. Redistributing Routes into EIGRP Using Route Maps
6. Creating a Default Route in EIGRP
7. Disabling EIGRP on an Interface
8. EIGRP Route Summarization
9. Adjusting EIGRP Metrics
10. Adjusting Timers
11. Enabling EIGRP Authentication
12. Logging EIGRP Neighbor State Changes
13. Limiting EIGRP’s Bandwidth Utilization
14. EIGRP Stub Routing
15. Route Tagging
16. Viewing EIGRP Status
Chapter 8 OSPF
1. Introduction
2. Configuring OSPF
3. Filtering Routes in OSPF
4. Adjusting OSPF Costs
5. Creating a Default Route in OSPF
6. Redistributing Static Routes into OSPF
7. Redistributing External Routes into OSPF
8. Manipulating DR Selection
9. Setting the OSPF RID
10. Enabling OSPF Authentication
11. Selecting the Appropriate Area Types
12. Summarizing Routes in OSPF
13. Disabling OSPF on Certain Interfaces
14. OSPF Route Tagging
15. Logging OSPF Adjacency Changes
16. Adjusting OSPF Timers
17. Viewing OSPF Status with Domain Names
18. Debugging OSPF
Chapter 9 BGP
1. Introduction
2. Configuring BGP
3. Using eBGP Multihop
4. Adjusting the Next-Hop Attribute
5. Connecting to Two ISPs
6. Connecting to Two ISPs with Redundant Routers
7. Restricting Networks Advertised to a BGP Peer
8. Adjusting Local Preference Values
9. Load Balancing
10. Removing Private ASNs from the AS Path
11. Filtering BGP Routes Based on AS Paths
12. Reducing the Size of the Received Routing Table
13. Summarizing Outbound Routing Information
14. Prepending ASNs to the AS Path
15. Redistributing Routes with BGP
16. Using Peer Groups
17. Authenticating BGP Peers
18. Putting It All Together
Chapter 10 Frame Relay
1. Introduction
2. Setting Up Frame Relay withPoint-to-Point Subinterfaces
3. Adjusting LMI Options
4. Setting Up Frame Relay with Map Statements
5. Using Multipoint Subinterfaces
6. Configuring Frame Relay SVCs
7. Simulating a Frame Relay Cloud
8. Compressing Frame Relay Data on a Subinterface
9. Compressing Frame Relay Data with Maps
10. Viewing Frame Relay Status Information
Chapter 11 Queueing and Congestion
1. Introduction
2. Fast Switching and CEF
3. Setting the DSCP or TOS Field
4. Using Priority Queueing
5. Using Custom Queueing
6. Using Custom Queues with Priority Queues
7. Using Weighted Fair Queueing
8. Using Class-Based Weighted Fair Queueing
9. Controlling Congestion with WRED
10. Using RSVP
11. Using Generic Traffic Shaping
12. Using Frame-Relay Traffic Shaping
13. Using Committed Access Rate
14. Implementing Standards-BasedPer-Hop Behavior
15. Viewing Queue Parameters
Chapter 12 Tunnels and VPNs
1. Introduction
2. Creating a Tunnel
3. Tunneling Foreign Protocols in IP
4. Tunneling with Dynamic Routing Protocols
5. Viewing Tunnel Status
6. Creating an EncryptedRouter-to-Router VPN
7. Generating RSA Keys
8. Creating a Router-to-Router VPN with RSA Keys
9. Creating a VPN Between a Workstation and a Router
10. Check IPSec Protocol Status
Chapter 13 Dial Backup
1. Introduction
2. Automating Dial Backup
3. Using Dialer Interfaces
4. Using an Async Modem on the AUX Port
5. Using Backup Interfaces
6. Using Dialer Watch
7. Ensuring Proper Disconnection
8. View Dial Backup Status
9. Debugging Dial Backup
Chapter 14 NTP and Time
1. Introduction
2. Timestamping Router Logs
3. Setting the Time
4. Setting the Time Zone
5. Adjusting for Daylight Saving Time
6. Synchronizing the Time on All Routers (NTP)
7. Configuring NTP Redundancy
8. Setting the Router as the NTP Master for the Network
9. Changing NTP Synchronization Periods
10. Using NTP to Send Periodic Broadcast Time Updates
11. Using NTP to Send Periodic Multicast Time Updates
12. Enabling and Disabling NTP Per Interface
13. NTP Authentication
14. Limiting the Number of Peers
15. Restricting Peers
16. Setting the Clock Period
17. Checking the NTP Status
18. Debugging NTP
Chapter 15 DLSw
1. Introduction
2. Configuring DLSw
3. Using DLSw to Bridge Between Ethernet and Token Ring
4. Converting Ethernet and Token Ring MAC Addresses
5. Configuring SDLC
6. Configuring SDLC for Multidrop Connections
7. Using STUN
8. Using BSTUN
9. Controlling DLSw Packet Fragmentation
10. Tagging DLSw Packets for QoS
11. Supporting SNA Priorities
12. DLSw+ Redundancy and Fault Tolerance
13. Viewing DLSw Status Information
14. Viewing SDLC Status Information
15. Debugging DSLw
Chapter 16 Router Interfaces and Media
1. Introduction
2. Viewing Interface Status
3. Configuring Serial Interfaces
4. Using an Internal T1 CSU/DSU
5. Using an Internal ISDN PRI Module
6. Using an Internal 56Kbps CSU/DSU
7. Configuring an Async Serial Interface
8. Configuring ATM Subinterfaces
9. Setting Payload Scrambling on an ATM Circuit
10. Configuring Ethernet Interface Features
11. Configuring Token Ring Interface Features
12. Connecting VLAN Trunks With ISL
13. Connecting VLAN Trunks with 802.1Q
Chapter 17 Simple Network Management Protocol
1. Introduction
2. Configuring SNMP
3. Extracting Router Information via SNMP Tools
4. Recording Important Router Information for SNMP Access
5. Extracting Inventory Information from a List of Routers with SNMP
6. Using Access Lists to Protect SNMP Access
7. Logging Unauthorized SNMP Attempts
8. Limiting MIB Access
9. Using SNMP to Modify a Router’s Running Configuration
10. Using SNMP to Copy a New IOS Image
11. Using SNMP to Perform Mass Configuration Changes
12. Preventing Unauthorized Configuration Modifications
13. Making Interface Table Numbers Permanent
14. Enabling SNMP Traps and Informs
15. Sending syslog Messages as SNMP Traps and Informs
16. Setting SNMP Packet Size
17. Setting SNMP Queue Size
18. Setting SNMP Timeout Values
19. Disabling Link Up/Down Traps per Interface
20. Setting the IP Source Address for SNMP Traps
21. Using RMON to Send Traps
22. Enabling SNMPv3
23. Using SAA
Chapter 18 Logging
1. Introduction
2. Enabling Local Router Logging
3. Setting the Log Size
4. Clearing the Router’s Log
5. Sending Log Messages to Your Screen
6. Using a Remote Log Server
7. Enabling Syslog on a Unix Server
8. Changing the Default Log Facility
9. Restricting What Log Messages Are Sent to the Server
10. Setting the IP Source Address for Syslog Messages
11. Logging Router Syslog Messages in Different Files
12. Maintaining Syslog Files on the Server
13. Testing the Syslog Sever Configuration
14. Preventing the Most Common Messages from Being Logged
15. Rate-Limiting Syslog Traffic
Chapter 19 Access Lists
1. Introduction
2. Filtering by Source or Destination IP Address
3. Adding a Comment to an ACL
4. Filtering by Application
5. Filtering Based on TCP Header Flags
6. Restricting TCP Session Direction
7. Filtering Multiport Applications
8. Filtering Based on DSCP and TOS
9. Logging when an Access List Is Used
10. Logging TCP Sessions
11. Analyzing ACL Log Entries
12. Using Named and Reflexive Access Lists
13. Dealing with Passive Mode FTP
14. Using Context-Based Access Lists
Chapter 20 DHCP
1. Introduction
2. Using IP Helper Addresses for DHCP
3. Limiting the Impact of IP Helper Addresses
4. Using DHCP to Dynamically Configure Router IP Addresses
5. Dynamically Allocating Client IP Addresses via DHCP
6. Defining DHCP Configuration Options
7. Defining DHCP Lease Periods
8. Allocating Static IP Addresses with DHCP
9. Configuring a DHCP Database Client
10. Configuring Multiple DHCP Servers per Subnet
11. Showing DHCP Status
12. Debugging DHCP
Chapter 21 NAT
1. Introduction
2. Configuring Basic NAT Functionality
3. Allocating External Addresses Dynamically
4. Allocating External Addresses Statically
5. Translating Some Addresses Statically and Others Dynamically
6. Translating in Both Directions Simultaneously
7. Rewriting the Network Prefix
8. Adjusting NAT Timers
9. Changing TCP Ports for FTP
10. Checking NAT Status
11. Debugging NAT
Chapter 22 Hot Standby Router Protocol
1. Introduction
2. Configuring Basic HSRP Functionality
3. Using HSRP Preempt
4. Making HSRP React to Problems on Other Interfaces
5. Load Balancing with HSRP
6. Redirecting ICMP with HSRP
7. Manipulating HSRP Timers
8. Using HSRP on a Token Ring Network
9. HSRP SNMP Support
10. Increasing HSRP Security
11. Showing HSRP State Information
12. Debugging HSRP
Chapter 23 IP Multicast
1. Introduction
2. Configuring Basic Multicast Functionality with PIM-DM
3. Routing Multicast Traffic with PIMSM and BSR
4. Routing Multicast Traffic with PIM-SM and Auto-RP
5. Configuring Routing for a Low Frequency Multicast Application
6. Configuring CGMP
7. Static Multicast Routes and Group Memberships
8. Routing Multicast Traffic with MOSPF
9. Routing Multicast Traffic with DVMRP
10. DVMRP Tunnels
11. Controlling Multicast Scope with TTL
12. Using Administratively Scoped Addressing
13. Exchanging Multicast Routing Information with MBGP
14. Using MSDP to Discover External Sources
15. Converting Broadcasts to Multicasts
16. Showing Multicast Status
17. Debugging Multicast Routing

Appendix External Software Packages
1. Perl
2. Expect
3. NET-SNMP
4. PuTTY
5. OpenSSH
6. Ethereal
Appendix IP Precedence, TOS, and DSCP Classifications
1. Combining TOS and IP Precedence to Mimic DSCP
2. RSVP
3. Queueing Algorithms
4. Dropping Packets and Congestion Avoidance
Colophon

Title:

Cisco Cookbook

By:

Kevin Dooley, Ian Brown

Publisher:

O'Reilly Media

Formats:

Print
Ebook
Safari Books Online

Print:

July 2003

Ebook:

March 2010

Pages:

912

Print ISBN:

978-0-596-00367-8

| ISBN 10:

0-596-00367-6

Ebook ISBN:

978-1-4493-8287-2

| ISBN 10:

1-4493-8287-8

Colophon

Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects. The animal on the cover of Cisco Cookbook is a black jaguar (Panthera onca), sometimes called a black panther. While the color of black (melanastic) jaguars differs from that of the more common golden-yellow variety, they are of the same species. Jaguars of all types are native to the tropics, swamps, and grasslands of Central and South America (and rumored to still exist in parts of the southwestern U.S.), but the black jaguar is usually found only in dense forests. They are between 4 and 6 feet long and have a long tail that is usually about 30 inches long. Males can weigh up to 250 pounds, while females are considerably smaller and rarely grow to more than 150 pounds. Even though black jaguars often appear to be a solid black in artistic renditions and photography, their coats still have the dark rings containing even darker spots that are a distinguishing feature of all jaguars. Also notable are their eyes, which are a shiny reflective yellow.

Jaguars will eat almost any animal, including sloths, pigs, deer, monkeys, and cattle. Their hooked claws allow them to catch fish, frogs, turtles, and even small alligators. Even though they sit at the top of the rain forest food chain, humans are a large threat to jaguars of all colors-- it's estimated that only 15,000 jaguars are left in the wild and the species is listed as near threatened. They are hunted for their coats (the black coat is greatly prized) and deforestation threatens their survival.

The black jaguar plays a large role in many South American religions, and is often considered a wise and divine animal who is associated with the worlds of magic and spirit. The Aztecs believed that the jaguar was the earthbound representative of their deity, and both the Mayans and Toltecs believed that their Sun God became a black jaguar at night in order to pass unseen through the underworld. Philip Dangler was the production editor and copyeditor for Cisco Cookbook. Sarah Sherman, Derek Di Matteo, Jane Ellin, and Claire Cloutier provided quality control. Julie Hawks wrote the index. Jamie Peppard and Mary Agner provided production assistance.

Ellie Volckhausen designed the cover of this book, based on a series design by Edie Freedman. The cover image is a 19th-century engraving from the Dover Pictorial Archive. Emma Colby produced the cover layout with QuarkXPress 4.1using Adobe's ITC Garamond font.

David Futato designed the interior layout. This book was converted by Andrew Savikas to FrameMaker 5.5.6 with a format conversion tool created by Erik Ray, Jason McIntosh, Neil Walls, and Mike Sierra that uses Perl and XML technologies. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed. The illustrations that appear in the book were produced by Robert Romano and Jessamyn Read using Macromedia FreeHand 9 and Adobe Photoshop 6. The tip and warning icons were drawn by Christopher Bing. This colophon was written by Philip Dangler.

Description

Table of Contents

Product Details

About the Author

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Recommended for You

Chapter 1 Router Configuration and File Management

Introduction

Configuring the Router via TFTP

Saving Router Configuration to Server

Booting the Router Using a Remote Configuration File

Storing Configuration Files Larger than NVRAM

Clearing the Startup Configuration

Loading a New IOS Image

Booting a Different IOS Image

Booting Over the Network

Copying an IOS Image to a Server

Copying an IOS Image Through the Console

Deleting Files from Flash

Partitioning Flash

Using the Router as a TFTP Server

Using FTP from the Router

Generating Large Numbers of Router Configurations

Changing the Configurations of Many Routers at Once

Extracting Hardware Inventory Information

Backing Up Router Configurations

Chapter 2 Router Management

Introduction

Creating Command Aliases

Managing the Router’s ARP Cache

Tuning Router Buffers

Using the Cisco Discovery Protocol

Disabling the Cisco Discovery Protocol

Using the Small Servers

Enabling HTTP Access to a Router

Using Static Hostname Tables

Enabling Domain Name Services

Disabling Domain Name Lookups

Specifying a Router Reload Time

Creating Exception Dump Files

Generating a Report of Interface Information

Generating a Report of Routing Table Information

Generating a Report of ARP Table Information

Generating a Server Host Table File

Chapter 3 User Access and Privilege Levels

Introduction

Setting Up User IDs

Encrypting Passwords

Using Better Encryption Techniques

Removing Passwords from a Router Configuration File

Deciphering Cisco’s Weak Password Encryption

Displaying Active Users

Sending Messages to Other Users

Changing the Number of VTYs

Changing VTY Timeouts

Restricting VTY Access by Protocol

Enabling Absolute Timeouts on VTY Lines

Implementing Banners

Disabling Banners on a Port

Disabling Router Lines

Reserving a VTY Port for Administrative Access

Restricting Inbound Telnet Access

Logging Telnet Access

Setting the Source Address for Telnet

Automating the Login Sequence

Using SSH for Secure Access

Changing the Privilege Level of IOS Commands

Defining Per-User Privileges

Defining Per-Port Privileges

Chapter 4 TACACS+

Introduction

Authenticating Login IDs from a Central System

Restricting Command Access

Losing Access to the TACACS+ Server

Disabling TACACS+ Authentication on a Particular Line

Capturing User Keystrokes

Logging System Events

Setting the IP Source Address for TACACS+ Messages

Obtaining Free TACACS+ Server Software

Sample Server Configuration Files

Chapter 5 IP Routing

Introduction

Finding an IP Route

Finding Types of IP Routes

Converting Different Mask Formats

Using Static Routing