TCP/IP Network Administration

The TCP/IP protocols (also called the "Internet protocols") are the "glue" that connects most UNIX networks (LANs). They're also responsible for the international "Internet": the world-wide network of networks that lets you send electronic mail from Maryland to Perth, Australia in a matter of minutes. Originally developed to support research on the ARPANET, the TCP/IP protocols have grown to maturity and widespread acceptance with UNIX.

TCP/IP Network Administration belongs on every system administrator's desk. It describes how to set up and administer a network of UNIX systems using the TCP/IP protocols. We take a practical approach: how to put your systems on the net (whether that means a LAN or the world-wide Internet) and keep them running. Even if your system isn't on a network now, it should be — and, within a year or two, it probably will be.

Topics covered include:

• Basic concepts: what the protocols are, addressing, name service
• Getting connected: the paperwork needed for connection to the Internet
• Basic system setup and configuration
• The "serial line" protocols, SLIP and PPP
• Routing, including the gated super-daemon
• Name service, including DNS/BIND
• Common network applications: the r utilities, and basic NFS and NIS
• sendmail configuration
• Setting up an anonymous FTP server
• Troubleshooting and security

1. Overview of TCP/IP
• TCP/IP and the Internet
• TCP/IP Features
• Protocol Standards
• A Data Communications Model
• TCP/IP Protocol Architecture
• Network Access Layer
• Internet Layer
• Internet protocol
• Internet Control Message Protocol
• Transport Layer
• User Datagram Protocol
• Transmission Control Protocol
• Application Layer
2. Delivering the Data
• Addressing, Routing, and Multiplexing
• The IP Address
• Address Depletion
• Subnets
• Internet Routing Architecture
• The Routing Table
• Address Resolution
• RARP
• Protocols, Ports, and Sockets
• Protocol Numbers
• Port Numbers
• Sockets
3. Name Service Concepts
• Names and Addresses
• The Host Table
• The NIC Host Table
• Domain Name Service
• The Domain Hierarchy
• Creating Domains and Subdomains
• Domain Names
• BIND, resolver, and named
• Network Information Service
4. Getting Started
• Connected and Non-connected Networks
• Obtaining an IP Address
• The Network Address Application
• Assigning Host Addresses
• Obtaining a Domain Name
• Obtaining an IN-ADDR.ARPA Domain
• Choosing a Host Name
• Planning Routing
• Obtaining an Autonomous System Number
• Defining the Subnet Mask
• Specifying the Broadcast Address
• Sample Planning Sheets
5. Basic Configuration
• Kernel Configuration
• The BSD Kernel Configuration File
• TCP/IP in the BSD Kernel
• BSD TCP/IP System Parameters
• Adding Network Devices
• System V Kernel Configuration
• SCO's netconfig
• The Internet Daemon
6. Configuring the Interface
• The ifconfig Command
• Determining the Interface with netstat
• Checking the Interface with ifconfig
• Assigning a Subnet Mask
• Setting the Broadcast Address
• Assigning the Network Interface Address
• The Other Command Options
• TCP/IP Over a Serial Line
• The Serial Protocols
• Choosing a Serial Protocol
• Installing SLIP
• SLIP for Sun
• Configuring the SLIP Interface
• slattach
• sliplogin
• Installing PPP
• Configuring the PPP Interface
7. Configuring Routing
• Common Routing Configurations
• The Minimal Routing Table
• Building a Static Routing Table
• Adding Static Routes
• The Variety of Routing Protocols
• Interior Routing Protocols
• Exterior Routing Protocols
• Choosing a Routing Protocol
• Routing Information Protocol
• Running RIP with routed
• Exterior Gateway Protocol
• Configuring the EGP User Process
• Gateway Routing Daemon
• gated's Preference Value
• Configuring gated
• Sample gated.conf Configurations
• The gated Command
8. Configuring DNS Name Service
• BIND: UNIX Name Service
• BIND Configurations
• Configuring the Resolver
• The Resolver Configuration File
• Configuring named
• The named.boot File
• Standard Resource Records
• The Cache Initialization File
• The named.local File
• The Reverse Domain File
• The named.hosts File
• Using nslookup
9. Network Applications
• The r Commands
• Securing the r Commands
• The .rhosts File
• The /usr/hosts Directory
• Network Information Service
• The /etc/netgroup File
• The Network File System
• NFS Daemons
• Exporting Filesystems
• The /etc/exports File
• Mounting Remote Filesystems
• The mount Command
• The /etc/fstab File
10. sendmail
• sendmail's Function
• Running sendmail as a Daemon
• sendmail Aliases
• The sendmail.cf File
• Locating a Sample sendmail.cf File
• General sendmail.cf Structure
• sendmail Configuration
• The Define Macro Command
• The Define Class Command
• The Set Option Command
• Defining Trusted Users
• Defining Mail Precedence
• Defining Mail Headers
• Defining Mailers
• Rewriting the Mail Address
• Pattern Matching
• Transforming the Address
• The Set Ruleset Command
• Modifying a sendmail.cf File
• Modifying Local Information
• Modifying the General Macros
• Modifying the Classes
• Modifying the Version Number
• Modifying Options
• Modifying the Rewrite Rules
• Testing sendmail.cf
• Testing the Rewrite Rules
11. Troubleshooting TCP/IP
• Approaching a Problem
• Troubleshooting Hints
• Diagnostic Tools
• Testing Basic Connectivity
• The ping Command
• Troubleshooting Network Access
• Troubleshooting with the ifconfig Command
• Troubleshooting with the arp Command
• Checking the Interface with netstat
• Network Hardware Problems
• Checking Routing
• Checking RIP Updates
• Tracing routes
• Checking Name Service
• dig, an Alternative to nslookup
• Analyzing Protocol Problems
• Packet Filters
• Protocol Case Study
12. Network Security
• Security Planning
• Assessing the Threat
• Distributed Control
• Writing a Security Policy
• Passwords
• Choosing a Password
• Password Software
• Other Precautions
• Check Application Security
• Remove Unnecessary Secure Terminals
• Remove Unnecessary Software
• Keep Software Updated
• Security Monitoring
• Know Your System
• Looking for Trouble
• COPS
• Limiting Access
• Encryption
• Firewalls
• Routing Control
• Access Control
• wrapper
• Words to the Wise
13. Internet Information Resources
• Anonymous ftp
• Creating an ftp Server
• Retrieving RFCs
• Retrieving RFCs by Mail
• Mailing Lists
• Resource Discovery Programs
• archie
• gopher
• The White Pages
• X.500
• More Reading

1. Network Contacts
• Internet Contacts
2. Forms, Forms, Forms
• Whois Registration
• Network Number Request
• Internet Domain Name Registration
• IN-ADDR.ARPA Registration
• Autonomous System Number Application
3. A gated Reference
• The gated Command
• Signal Processing
• The gated Configuration Language
• Directive Statements
• Trace Statements
• Definition Statements
• Protocol Statements
• The rip Statement
• The hello Statement
• The redirect Statement
• The egp Statement
• The bgp Statement
• Static Statements
• Control Statements
• The accept Statement
• The propagate Statement
• Preference Precedence
4. named Reference
• The named Command
• Signal Processing
• named.boot Configuration Commands
• Zone File Records
• Standard Resource Records
• Experimental Resource Record
5. Sample sendmail.cf
• The sendmail Configuration File
6. Selected TCP/IP Headers
• IP Datagram Header
• TCP Segment Header
• ICMP Parameter Problem Message Header
7. Reference for passwd+
• The Configuration File
• The GECOS Data
• Logging passwd+ Activities
• Password Tests
• Escape Sequences
• Final Words
8. Software Sources