Understanding TCP/IP and the Internet — A 3 Day Course

Synopsis

A TCP/IP fundamentals course providing theoretical and practical grounding in the operation of core TCP/IP and internet protocols.

This course starts from the position of something that almost all candidates are familiar with — web browsing — and ‘drills down’ from there down to the lowest levels of the TCP/IP stack: IP routing, packet structure, Network Address Translation (NAT), and so on. It also offers an overview of a number of other significant issues for those wanting to understand not only the technical structure of the internet, but how to apply it in their own organisations. Such issues include: e-mail; understanding firewalling and routing; and using SNMP for integrated management of network devices and applications.

Suitable For

IT managers, developers, system administrators and technical support staff who require a solid grounding in the fundamental technologies and protocols which underly the provision of Internet services.

As useful for those making purchasing or managerial decisions over IP networking goods and services, as it is for those engaged in technical implementation.

Delivery

Course contents focus on international IP standards, dealing with vendor-specific implementations only where they impinge on the normal operation of the key protocols, e.g. as do some proprietary mail exchangers.

The course provides for hands-on practical work, but because of the emphasis on building a fundamental conceptual understanding, there is less of it than one would typically find on a GBdirect course.

Publicly scheduled dates, locations, and prices

A schedule of dates for this course is not currently available. Please call 0800 651 0338 or use our contact form to enquire about places and availability.

Background to TCP/IP and the Internet

Overview of how the Internet is supposed to work
Foundations: Packet Switching
History and culture
Internet administration
Requests for Comments (RFCs)
TCP/IP: open standards-based application services
How RFCs and other standards affect TCP/IP
Protocol layering: Physical layer independence, OSI and TCP/IP
Components of TCP/IP networks
The TCP/IP misnomer: it's just IP

Web browsing explained

An analogy
Initial communication
Lost in the post
Order arrival
Order failure
Webpage failure
Further requests

Locating Resources by Name and Address

IP addresses are numeric
Locating resources by name
Numeric addresses
Name Resolution
DNS, the Domain Name Service

HTTP

HTTP communications
HTTP requests
Request lines
HTTP request headers
HTTP responses
Status lines
Status codes
Error status codes
HTTP response headers
Optional HTTP response headers
HTTP specification
HTTP details
Practising HTTP

Conversations and reliability

TCP — a reliable pipe
TCP connections
Multiple conversations
Port numbers
Multiple connections from many hosts
Multiple connections from one host

Conversations and packets: TCP

Conversations?
Streams and packets
What IP does
What TCP does
Protocol layering
Link layer
Internet layer
Transport layer
Application layer
The OSI reference model
OSI and TCP/IP
Problems with providing reliability
Sequence numbers
Positive acknowledgment
Sending acknowledgments
Three-way handshake
Choosing sequence numbers
Naïve acknowledgments
Sliding windows
Maximum segment size

IP addressing and routing

Binary numbers: a reminder
Limits of binary numbers
Masking with binary numbers
IP addresses
Network part and host part
Network part
Network masks
Variable-length subnet table
Network addresses and broadcast addresses
Address classes
The rise of classless addressing
Classful addressing in the modern world
Private network allocations
Loopback addresses
IP routing concepts
Routing decisions
Routing example: single host with dial-up
Routing example: host on directly-connected network
Routing example: gateway host
Routing tables
Scalability of routers
Summary of unavailable IP addresses

Connectionless application-level protocols: UDP

UDP is a connectionless protocol
Why use UDP?
Problem domains suitable for UDP
Application-layer protocols that use UDP
What UDP does
DNS: a UDP-based application protocol
UDP and congestion control: a problem
Reliable UDP is possible
Further reading

Fragmentation in IP

Frame and datagram sizes
Fragmentation
Where reassembly happens
The reassembly process
Datagram size tradeoffs
Path MTU Discovery

IP packet structure

Packet structure concepts
IP datagrams
IP options
Applicability of IP options
UDP packets
TCP segments

IP control messages

The need for control messages
The rôle of ICMP
Who sees ICMP error messages?
ICMP message format
Summary of ICMP message types
ICMP Echo Request
ICMP Echo Reply
ICMP Destination Unreachable
ICMP Source Quench
ICMP Time Exceeded
ICMP Parameter Problem

DNS

Before DNS
DNS
Domain names
Domain name hierarchy
Queries
Recursive and iterative queries
Kick-starting a query
The importance of caching
Domains and zones
Authoritative hosts
Delegating authority
Mail exchangers
Reverse name look-ups
DNS protocol
Zone files
Zone file syntax
A record: address
SOA record: authority
NS record: name server
Delegating with NS records
MX record: mail exchanger
PTR record: reverse DNS
CNAME record: alias

Present-day issues in IP networking

A history lesson
The modern world
The origins of address shortage
CIDR's effects on address shortage
Responses to address shortage
Proxy servers
Centralised email delivery
Proxy web servers
Web proxy details
Network Address Translation
NAT routers
NAT on outgoing datagrams
NAT on incoming datagrams
NAT is directional
NAT in datagram payloads
IPv6: the next-generation Internet
Network security
Packet-filtering firewalls
Firewall policies
Firewall rules
Common problems with packet filtering
Limitations of packet filtering

Email

Sending and receiving email
Email addressing
Message structure
MIME — Multipurpose Internet Mail Extensions
Sending a message
SMTP — Simple Mail Transfer Protocol
ESMTP — Extended SMTP
Mail exchangers
Delivering a message
Mail boxes
POP — Post Office Protocol
POP protocol overview
IMAP — Internet Message Access Protocol

SNMP: an IP management protocol

Network management protocols
SNMP: the Simple Network Management Protocol
Agents and managers
SNMP organisation
Object Identifiers
An example OID
Problems with SNMP