Network Protocols, Ports, and Communication

Vocabulary flashcards covering common network ports, protocols, IPsec components, and communication methods based on the lecture transcript.

FTP (File Transfer Protocol)

TCP 20 (active-mode data) and TCP 21 (control); used to transfer files between systems.

SSH (Secure Shell)

TCP 22; provides encrypted text-based console/remote access.

SFTP (SSH File Transfer Protocol)

TCP 22; provides secure, encrypted file transfers using SSH.

Telnet

TCP 23; provides remote console access but sends communication in cleartext.

SMTP (Simple Mail Transfer Protocol)

TCP 25; used for server-to-server email transfer and sending email.

SMTP with TLS

TCP 587; commonly used for encrypted SMTP email submission.

DNS (Domain Name System)

UDP 53; converts domain names into IP addresses. TCP 53 may be used for larger transfers.

DHCP (Dynamic Host Configuration Protocol)

UDP 67 and UDP 68; automatically provides IP addresses, subnet masks, and other network configuration.

TFTP (Trivial File Transfer Protocol)

UDP 69; provides very simple file transfers with no authentication.

HTTP (Hypertext Transfer Protocol)

TCP 80; used for web communication.

HTTPS (Hypertext Transfer Protocol Secure)

TCP 443; used for encrypted web communication using TLS.

NTP (Network Time Protocol)

UDP 123; synchronizes clocks between network devices.

SNMP (Simple Network Management Protocol)

UDP 161; gathers statistics and monitors network devices.

SNMP Trap

UDP 162; allows network devices to send alerts and notifications to a management system.

LDAP (Lightweight Directory Access Protocol)

TCP 389; stores and retrieves information from a network directory.

SMB (Server Message Block)

TCP 445; used primarily for Windows file and printer sharing.

Syslog

UDP 514; provides standardized message logging, often sending logs to a central collector.

LDAPS (LDAP Secure)

TCP 636; provides LDAP directory services over SSL/TLS.

MS-SQL (Microsoft SQL Server)

TCP 1433; used for Microsoft SQL Server database connections.

RDP (Remote Desktop Protocol)

TCP 3389; allows remote access to a Windows desktop or application.

SIP (Session Initiation Protocol)

TCP 5060 and TCP 5061; used for VoIP signaling and managing voice/video sessions.

ICMP (Internet Control Message Protocol)

Used by network devices to send administrative, status, and error messages; commonly used by ping.

GRE (Generic Routing Encapsulation)

Encapsulates traffic inside IP to create a tunnel between endpoints; GRE does not provide built-in encryption.

VPN (Virtual Private Network)

Provides encrypted private communication across a public network.

VPN Concentrator

Device that handles VPN encryption and decryption; often integrated into a firewall.

Site-to-Site VPN

Connects two networks together through a VPN, usually as an always-on or nearly always-on connection.

IPsec (Internet Protocol Security)

Provides Layer 3 security through authentication, encryption, confidentiality, integrity, and anti-replay protection.

IKE (Internet Key Exchange)

Used to securely negotiate encryption keys and security associations for IPsec.

IKE Phase I

Uses Diffie-Hellman to establish a shared secret and uses UDP 500.

IKE Phase II

Negotiates encryption details and inbound/outbound security associations for IPsec.

AH (Authentication Header)

IPsec protocol that provides authentication and integrity for packets.

ESP (Encapsulating Security Payload)

IPsec protocol that provides encryption and can also provide authentication and integrity.

AH vs ESP

AH focuses on authentication and integrity; ESP provides encryption plus authentication/integrity capabilities.

GRE vs VPN

GRE creates a tunnel but does not provide encryption by itself; a VPN provides encrypted private communication.

Unicast

One-to-one communication; one station sends information to one destination.

Multicast

One-to-many-of-many communication; traffic is delivered only to interested systems.

Anycast

One-to-one-of-many communication; the same address exists on multiple endpoints and traffic is routed to the closest endpoint.

Broadcast

One-to-all communication; one packet is sent to everyone within the broadcast domain.

IPv4 Broadcast

IPv4 supports broadcast communication.

IPv6 Broadcast

IPv6 does not use broadcast; multicast is used instead.