Index

A

• address / What's your address?
• ad hoc mode / Wi-Fi
• American Encryption Standard (AES) / Symmetric ciphers
• Analog-to-Digital Converter (ADC) / Microcontrollers
• anycast / Multicast, broadcast, and anycast
• Apache / Alternatives to TLS
• Application-Specific Integrated Circuit (ASIC) / FPGAs
• application layer / OSI layer model
• application programming interfaces (APIs) / What are sockets?
• asymmetric ciphers / Asymmetric ciphers
• asymmetric encryption / Asymmetric ciphers
• Asynchronous Serial / Single-board computers
• AT commands / External transceivers and modems

B

• banner / Establishing a connection
• Berkeley sockets
  • versus Winsock sockets / Berkeley sockets versus Winsock sockets
  • header files / Header files
  • socket data type / Socket data type
  • invalid sockets / Invalid sockets
  • closing sockets / Closing sockets
  • error handling / Error handling
• Bluetooth / Bluetooth
• Bluetooth smart watch connection / Bluetooth
• broadcast addressing / Multicast, broadcast, and anycast
• bulk encryption algorithm / How TLS uses ciphers

C

• Central Processing Unit (CPU) / Single-board computers
• certificate pinning / Self-signed certificates with OpenSSL
• certificates / Certificates, Certificates, Certificates
• CGI standard / Alternatives to TLS
• chain-of-trust model / Certificates
• chat room
  • building / Building a chat room
• cipher / Encryption basics
• cipher suites / How TLS uses ciphers
• ciphertext / Encryption basics
• classless inter-domain routing (CIDR) / What is an address?
• client-server model / Clients and servers
• client authentication
  • about / Client authentication
  • no authentication / Client authentication
  • password authentication / Client authentication
  • public key / Client authentication
  • keyboard-interactive / Client authentication
  • Generic Security Service Application Program Interface (GSS-API) / Client authentication
• congestion-avoidance scheme / Congestion control
• congestion control methods / Congestion control
• connectivity options, IoT
  • about / Connectivity options
  • Wi-Fi / Wi-Fi
  • Ethernet / Ethernet
  • cellular / Cellular
  • Bluetooth / Bluetooth
  • IEEE 802.15.4 WPANs / IEEE 802.15.4 WPANs
• Constrained Application Protocol (CoAP) / IoT protocols
• Content-Type
  • returning, from filename / Returning Content-Type from a filename
• content types / Content types
• C programming language
  • about / The internet and C
  • network adapters, listing / Listing network adapters from C

D

• data encapsulation / Data encapsulation
• Data Encryption Standard (DES) / Symmetric ciphers
• datagram / OSI layer model
• Datagram Transport Layer Security (DTLS) / A simple HTTPS client
• data link layer / OSI layer model
• deadlock
  • avoiding / TCP flow control and avoiding deadlock
• decryption / Encryption basics
• deep packet inspection / Deep packet inspection
• defense in depth approach / Application security and safety
• Diffie-Hellman key exchange algorithm / Symmetric ciphers
• Digital-to-Analog Converter (DAC) / Microcontrollers
• Digital Rights Management (DRM) / Firmware updates
• DNS message
  • printing / Printing a DNS message
• DNS message name
  • printing / Printing a DNS message name
• DNS over HTTPS (DoH) / DNS security
• DNS protocol
  • about / The DNS protocol
  • message format / DNS message format
  • message header format / DNS message header format
  • question format / Question format
  • answer format / Answer format
  • endianness / Endianness
• DNS query
  • about / A simple DNS query
  • sending / Sending the query
• DNS query program / A DNS query program
• DNS record types / DNS record types
• DNS security / DNS security
• DNS transport over TCP / The DNS protocol
• Domain-based Message Authentication, Reporting, and Conformance (DMARC) / Spam-blocking pitfalls
• DomainKeys Identified Mail (DKIM) / Spam-blocking pitfalls
• domain name / Domain names
• Domain Name System (DNS) / Domain names
• Domain Name System Security Extensions (DNSSEC) / DNS security
• domain validation / Certificates
• dual-stack configuration / Internet Protocol

E

• echo reply / Testing reachability
• Echo Reply message / How traceroute works
• echo request / Testing reachability
• EEPROM / Microcontrollers
• elliptic-curve cryptography (ECC) / Asymmetric ciphers
• email
  • format / The format of an email
• email file attachments / Email file attachments
• email servers
  • about / Email servers
  • finding / Finding an email server
• encrypted server name identification (ESNI) / Server name identification
• encryption
  • about / Encryption basics
  • basics / Encryption basics
  • symmetric ciphers / Symmetric ciphers
  • asymmetric ciphers / Asymmetric ciphers
  • Transport Layer Security (TLS) / How TLS uses ciphers
• endianness / Endianness
• enhanced emails / Enhanced emails
• ephemeral port / Putting it together
• ephemeral port number / A simple UDP client
• error descriptions
  • obtaining / Obtaining error descriptions
• error handling / Error handling
• ESP8266 microcontroller / Microcontrollers
• Ethernet / Ethernet
• Extended Validation (EV) certificates / Certificates
• external transceivers / External transceivers and modems

F

• FastCGI standard / Alternatives to TLS
• Field-Programmable Gate Arrays (FPGAs) / FPGAs
• file
  • downloading / Downloading a file
• File Transfer Protocol (FTP) / Local networks and address translation
• firewalls / Network security
• firmware updates / Firmware updates
• FLASH / Microcontrollers
• frame / OSI layer model

G

• General-Purpose Input/Output (GPIO) / Single-board computers

H

• hardware choices, IoT
  • about / Hardware choices
  • Single-Board Computers (SBCs) / Single-board computers
  • microcontroller / Microcontrollers
  • Field-Programmable Gate Arrays (FPGAs) / FPGAs
• Hardware Description Languages (HDL) / FPGAs
• Hayes command set / External transceivers and modems
• hostname resolution
  • working / How hostname resolution works
• HTTP POST requests
  • about / HTTP POST requests
  • form data, encoding / Encoding form data
  • file uploads / File uploads
• HTTP protocol
  • about / The HTTP protocol, HTTPS and OpenSSL summary
  • response body length / Response body length
• HTTP request format / HTTP request format
• HTTP request types
  • GET / HTTP request types
  • HEAD / HTTP request types
  • POST / HTTP request types
  • PUT / HTTP request types
  • DELETE / HTTP request types
  • TRACE / HTTP request types
  • CONNECT / HTTP request types
  • OPTIONS / HTTP request types
• HTTP response codes / HTTP response codes
• HTTP response format / HTTP response format
• HTTPS client / A simple HTTPS client
• HTTP server
  • about / The HTTP server
  • architecture / The server architecture
• HTTPS server
  • about / A full HTTPS server
  • challenges / HTTPS server challenges
• HTTPS server, with OpenSSL
  • about / HTTPS server with OpenSSL
  • time server example / Time server example
• HTTP web client
  • implementing / Implementing a web client
• Hypertext Markup Language (HTML) / HTTPS overview
• Hypertext Transfer Protocol Secure (HTTPS)
  • overview / HTTPS overview
  • authentication / HTTPS overview
  • encryption / HTTPS overview
  • integrity / HTTPS overview
  • about / HTTPS and OpenSSL summary

I

• IEEE 802.15.4 WPANs / IEEE 802.15.4 WPANs
• Industry 4.0 / What is the IoT?
• inetd / Networking with inetd
• infrastructure mode / Wi-Fi
• Inter-Integrated Circuit (I2C) / Single-board computers
• inter-process communication (IPC) / What are sockets?
• International Data Encryption Algorithm (IDEA) / Symmetric ciphers
• internet / The internet and C
• Internet Assigned Numbers Authority (IANA) / Port numbers, Content types
• Internet Control Message Protocol (ICMP) / Internet routing, Testing reachability
• Internet Engineering Task Force (IETF) / Internet Protocol
• Internet Message Access Protocol (IMAP) / Email servers
• Internet of Things (IoT)
  • about / The internet and C, What is the IoT?
  • hardware choices / Hardware choices
• Internet Protocol
  • about / Internet Protocol
  • address / What is an address?
  • local networks and address translation / Local networks and address translation
  • subnetting / Subnetting and CIDR
  • CIDR / Subnetting and CIDR
• internet routing / Internet routing
• Internet Service Providers (ISPs) / Internet Protocol, How hostname resolution works, SMTP security, Wi-Fi
• IoT, ethics
  • about / Ethics of IoT
  • privacy / Privacy and data collection
  • data collection / Privacy and data collection
  • end-of-life planning / End-of-life planning
  • security / Security
• IoT protocols / IoT protocols
• ipconfig command / What's your address?
• IP lookup
  • example program / IP lookup example program
• IPv4 / Internet Protocol, Supporting both IPv4 and IPv6
• IPv4 addresses / What is an address?
• IPv6
  • about / Internet Protocol, Supporting both IPv4 and IPv6
  • working with / Working with IPv6
• IPv6 addresses / What is an address?

K

• key exchange algorithm / How TLS uses ciphers

L

• Let's Encrypt / Certificates
• libssh
  • about / libssh
  • testing / Testing out libssh
  • connection, establishing / Establishing a connection
• link-local addresses / What is an address?
• Local Area Networks (LANs) / Local networks and address translation
• local connection
  • checking / Checking local connections
  • snooping / Snooping on connections
  • deep packet inspection / Deep packet inspection
  • network traffic, capturing / Capturing all network traffic
• local port / Putting it together, A simple UDP server, A simple UDP client, Socket's local address
• loopback address / What is an address?
• low-rate wireless personal area networks (LR-WPAN) / IEEE 802.15.4 WPANs

M

• mail submission / Email servers
• mail transmission / Email servers
• man-in-the-middle attack / Symmetric ciphers
• Maximum Segment Size (MSS) / The Nagle algorithm
• mesh network topology / IEEE 802.15.4 WPANs
• message authentication algorithm (MAC) / How TLS uses ciphers
• Message Authentication Code (MAC) / Security
• Message Queuing Telemetry Transport (MQTT) / IoT protocols
• microcontroller / Microcontrollers
• microservices / A TCP server
• MIME type / Content types
• modem / External transceivers and modems
• multicast / Multicast, broadcast, and anycast
• multiple connections buffering
  • about / Multiple connections buffering
  • get_client() function / get_client()
  • drop_client() function / drop_client()
  • get_client_address() function / get_client_address()
  • wait_on_clients() function / wait_on_clients()
  • send_400() function / send_400()
  • send_404() function / send_404()
  • serve_resource() function / serve_resource()
• Multipurpose Internet Mail Extensions (MIME) / Enhanced emails

N

• Nagle algorithm / The Nagle algorithm
• name/address translation functions
  • about / Name/address translation functions
  • getaddrinfo(), using / Using getaddrinfo()
  • getnameinfo(), using / Using getnameinfo()
• Netstat / Checking local connections
• network adapters
  • listing, from C programming language / Listing network adapters from C
  • listing, on Windows / Listing network adapters on Windows
  • listing, on Linux / Listing network adapters on Linux and macOS
  • listing, on macOS / Listing network adapters on Linux and macOS
• Network Address Translation (NAT) / Local networks and address translation
• network address translation (NAT) / A simple UDP server
• networked code
  • security / Security and robustness
  • robustness / Security and robustness
• networked program
  • about / Our first program
  • motivating example / A motivating example
  • creating / Making it networked
• networking
  • with inetd / Networking with inetd
• network layer / OSI layer model
• network monitoring
  • purpose / The purpose of network monitoring
• network security
  • about / Network security
  • application security / Application security and safety
  • application safety / Application security and safety
• network testing
  • etiquette / Network-testing etiquette
• network traffic
  • capturing / Capturing all network traffic
• Nginx / Alternatives to TLS

O

• open source servers / Open source servers
• OpenSSL
  • about / OpenSSL, HTTPS and OpenSSL summary
  • encrypted sockets / Encrypted sockets with OpenSSL
  • certificates / Certificates
  • self-signed certificates / Self-signed certificates with OpenSSL
  • HTTPS server / HTTPS server with OpenSSL
  • alternatives / OpenSSL alternatives
• Open Systems Interconnection model (OSI model) / OSI layer model
• Open Web Application Security Project (OWASP) / Security
• OSI layer model
  • about / OSI layer model
  • physical layer / OSI layer model
  • data link layer / OSI layer model
  • network layer / OSI layer model
  • transport layer / OSI layer model
  • session layer / OSI layer model
  • presentation layer / OSI layer model
  • application layer / OSI layer model

P

• packet / OSI layer model
• percent encoding / Encoding form data
• physical layer / OSI layer model
• Ping utility / The purpose of network monitoring
• plaintext / Encryption basics
• polling / Polling non-blocking sockets
• Portable Operating System Interface (POSIX) / What are sockets?
• port numbers / Port numbers
• postcards / Two types of sockets
• Post Office Protocol (POP) / Email servers
• Pre-Shared Key (PSK) / Security
• presentation layer / OSI layer model
• Private Key / Asymmetric ciphers
• protocols / OSI layer model
• public-key authentication / The SSH protocol
• public-key encryption / Asymmetric ciphers
• Public Key / Asymmetric ciphers
• Pulse Width Modulation (PWM) / Single-board computers, Microcontrollers

R

• Random Access Memory (RAM) / Single-board computers
• Raspberry Pi Zero W / Single-board computers
• raw sockets / Raw sockets
• reachability
  • testing / Testing reachability
  • route, checking / Checking a route
  • traceroute, working / How traceroute works
  • raw sockets / Raw sockets
• remote command
  • executing / Executing a remote command
• request line / HTTP request format, The HTTP server
• Rijndael / Symmetric ciphers
• Rivest-Shamir-Adleman (RSA) / Asymmetric ciphers

S

• Secure Copy Protocol (SCP) / Downloading a file
• Secure Hypertext Internet of Things (SHIoT) / Security
• Secure Shell fingerprint (SSHFP) / SSH authentication
• Secure Socket Layer (SSL) / HTTPS overview
• segment / OSI layer model
• self-signed certificates
  • with OpenSSL / Self-signed certificates with OpenSSL
• send() method
  • blocking behavior on / Blocking on send()
• Sender Policy Framework (SPF) / DNS record types, Spam-blocking pitfalls
• Serial Peripheral Interface (SPI) / Single-board computers
• server authentication / Certificates, Server authentication
• server name identification (SNI) / Server name identification
• server socket
  • creating / Creating the server socket
• session channel type / Executing a remote command
• session layer / OSI layer model
• Single-Board Computers (SBCs) / Single-board computers
• site-local addresses / What is an address?
• SMTP
  • about / Email servers
  • security / SMTP security
• SMTP client program / A simple SMTP client program
• SMTP dialog / SMTP dialog
• SMTP relay / Email servers
• socket
  • implementing / Putting it together
  • about / What are sockets?
  • setting up / Socket setup
  • connection-oriented / Two types of sockets
  • connectionless / Two types of sockets
  • types / Two types of sockets
  • local address / Socket's local address
  • multiplexing with / Multiplexing with a large number of sockets
• socket functions
  • socket() / Socket functions
  • bind() / Socket functions
  • listen() / Socket functions
  • connect() / Socket functions
  • accept() / Socket functions
  • send() / Socket functions
  • recv() / Socket functions
  • sendto() / Socket functions
  • recvfrom() / Socket functions
  • close() / Socket functions
  • shutdown() / Socket functions
  • select() / Socket functions
  • getnameinfo() / Socket functions
  • getaddrinfo() / Socket functions
  • setsockopt() / Socket functions
  • fcntl() / Socket functions
  • ioctlsocket() / Socket functions
• socket program
  • anatomy / Anatomy of a socket program
  • TCP program flow / TCP program flow
  • UDP program flow / UDP program flow
• spam-blocking
  • pitfalls / Spam-blocking pitfalls
• SSH authentication
  • about / SSH authentication
  • server authentication / Server authentication
  • client authentication / Client authentication
• SSH protocol / The SSH protocol
• symmetric cipher / Symmetric ciphers
• synchronous multiplexing, with select()
  • about / Synchronous multiplexing with select()
  • select() timeout / select() timeout
  • iteration, through fd_set / Iterating through an fd_set
  • select(), on non-sockets / select() on non-sockets

T

• tab feature / Multiplexing TCP connections
• TCP/IP layer model
  • about / TCP/IP layer model
  • Network Access layer / TCP/IP layer model
  • Internet layer / TCP/IP layer model
  • Host-to-Host layer / TCP/IP layer model
  • Process/Application layer / TCP/IP layer model
• TCP/IP protocol suite / TCP/IP layer model
• TCP client
  • about / A TCP client
  • code / TCP client code
• TCP connection
  • setup phase / TCP socket tips
  • data-transfer phase / TCP socket tips
  • tear-down phase / TCP socket tips
• TCP connections, multiplexing
  • about / Multiplexing TCP connections
  • non-blocking sockets, polling / Polling non-blocking sockets
  • forking / Forking and multithreading
  • multithreading / Forking and multithreading
  • select() function / The select() function
• TCP fallback / The DNS protocol
• TCP flow control / TCP flow control and avoiding deadlock
• TCP four-way closing handshake / Connection tear-down
• TCP program flow / TCP program flow
• TCP server
  • about / A TCP server
  • code / TCP server code
• TCP slow start algorithm / Congestion control
• TCP socket, tips
  • about / TCP socket tips
  • timeout, on connect() / Timeout on connect()
  • TCP flow control / TCP flow control and avoiding deadlock
  • deadlock, avoiding / TCP flow control and avoiding deadlock
  • congestion control / Congestion control
  • Nagle algorithm / The Nagle algorithm
  • delayed acknowledgment / Delayed acknowledgment
  • connection tear-down / Connection tear-down
  • shutdown() function / The shutdown() function
  • address-in-use errors, preventing / Preventing address-in-use errors
  • message, sending to disconnected peer / Sending to a disconnected peer
• TCP stream protocol / TCP is a stream protocol
• Telnet / The SSH protocol
• time-to-live (TTL) / How hostname resolution works, How traceroute works
• Time Exceeded message / How traceroute works
• Tiny Encryption Algorithm (TEA) / Symmetric ciphers
• TLS protocol
  • about / The TLS protocol
  • certificates / Certificates
  • server name identification (SNI) / Server name identification
  • alternatives / Alternatives to TLS
• TLS termination proxy / Alternatives to TLS
• tooling options
  • tcpdump / Snooping on connections
  • Wireshark / Snooping on connections
• traceroute
  • working / How traceroute works
• tracert / Checking a route
• tracker / Anatomy of a socket program
• Transmission Control Protocol (TCP) / OSI layer model, Two types of sockets, The HTTP server, The SSH protocol, TCP socket tips
• transport layer / OSI layer model
• Transport Layer Security (TLS)
  • ciphers, used / How TLS uses ciphers
• Tshark
  • reference / Snooping on connections

U

• UDP client
  • methods / UDP client methods
  • about / A first UDP client/server, A simple UDP client
• UDP program flow / UDP program flow
• UDP server
  • methods / UDP server methods
  • about / A first UDP client/server, A simple UDP server, A UDP server
• UDP sockets / How UDP sockets differ
• unicast addressing / Multicast, broadcast, and anycast
• Uniform Resource Locators (URL)
  • about / What's in a URL
  • parsing / Parsing a URL
• URL encoding / Encoding form data
• User Datagram Protocol (UDP) / OSI layer model, Two types of sockets, A simple HTTPS client

V

• Verilog / FPGAs
• VHSIC Hardware Description Language (VHDL) / FPGAs
• Virtual Private Network (VPN) / Cellular
• Virtual Private Servers (VPS) / Establishing a connection

W

• Watch-Dog Timers (WDT) / Microcontrollers
• web server
  • main loop / The main loop
• Wi-Fi / Wi-Fi
• Winsock / Listing network adapters on Windows, What are sockets?
• Winsock sockets
  • versus Berkeley sockets / Berkeley sockets versus Winsock sockets
• Wireless Access Point (WAP) / Wi-Fi
• Wireless Local Area Network (WLAN) / Wi-Fi
• Wireless Personal Area Networks (WPAN) / Bluetooth
• Wireshark / Deep packet inspection
• wolfSSL / Security