Online Courses
CCNA 200-301
Online Courses
CCNA 200-301
  • Introduction
  • Interfaces And Cables
    • Ethernet
    • UTP Cables
    • Fiber Optic
    • UTP vs Fiber-Optic
    • Quiz
  • OSI Model & TCP/IP Suite
    • Networking Model
      • OSI Model
        • Application
        • Presentation
        • Session
        • Transport
        • Network
        • Data Link
        • Physical
      • PDUs
      • TCP/IP Suite
    • Quiz
  • Intro to the CLI
    • What is a CLI
      • Global Configuration Mode
      • Enable Password
    • Configuration Files
    • Canceling commands
    • Quiz
  • Ethernet LAN Switching
    • Local Area Network (LAN)
    • MAC Address
    • Ethernet Frame
    • Quiz 1
    • ARP
    • Ping
    • Quiz 2
  • IPv4 Addressing
    • Network Layer Review
    • IPv4
    • Quiz
    • Cisco CLI
    • Quiz
  • Switch Interfaces
    • CLI
    • Full/Half Duplex
    • CSMA/CD
    • Speed / Duplex Auto-Negotiation
    • Interface Errors
    • Quiz
  • IPv4 Header
    • Fields
      • Do Not Fragment
    • Quiz
  • Static Routing
    • Topology
    • CLI
    • Default Route
    • Static Route
    • Most Specific Matching Route
    • Quiz
  • Subnetting
    • Subnetting
    • Quiz
    • Variable-Length Subnet Masks
  • VLANs
    • What is a LAN ?
    • VLAN Configuration
    • Quiz 1
    • Example
    • Trunk Ports
      • Configuration
    • VLAN Ranges
    • Native VLAN
    • Router on a Stick (ROAS)
    • Quiz 2
    • Native VLAN on Router
    • Layer 3 (Multilayer) Switches
    • Quiz 3
  • DTP/VTP
    • DTP
    • VTP
    • Quiz
  • Spanning Tree Protocol
    • Network Redundancy
    • Layer 2 Loops
    • Spanning Tree Protocol
      • Exercise
    • STP Port Role Selection
      • Exercise
    • Blocking Ports
    • Quiz 1
    • States
    • Timers
    • BPDU
    • STP Toolkit
    • Configurations
    • Load-Balancing
      • Quiz
    • Quiz 2
  • Rapid Spanning Tree Protocol
    • STP Version Comparison
    • RSTP Intro
    • Quiz 1
    • BPDU
    • Link Types
    • Quiz 2
  • EtherChannel
    • Why EtherChannel is needed?
    • Load-Balancing
      • Configuration
    • PAgP, LACP, and Static
      • PAgP
      • LACP
      • Static
      • Manually Configure the Negotiation Protocol
    • EtherChannel Requirements
    • EtherChannel Verification
    • Layer 3 EtherChannel
    • Quiz
  • Dynamic Routing
    • Network Topology
    • Dynamic Routing
    • Types
      • Distance Vector Protocols
      • Link State Protocols
    • Metrics
    • Administrative Distance
      • Floating Static Routes
    • Quiz
    • RIP
      • RIPv1 & RIPv2
      • RIP Configuration
    • EIGRP
      • EGRP Configuration
    • Quiz
    • OSPF
      • Areas
      • Configuration
      • Cost
      • Neighbors
      • Loopback Interfaces
      • Network Types
      • Neighbor Requirements
      • LSA Types
    • Configuration
    • Quiz
  • First Hop Redundancy Protocols
    • Introduction
    • HSRP
    • VRRP
    • GLBP
    • Comparing FHRPs
    • Configuring HSRP
    • Quiz
  • TCP & UDP
    • Basic of Layer 4
      • Port Numbers / Session Multiplexing
    • TCP
    • UDP
    • Comparing TCP & UDP
    • Port Numbers
    • Quiz
  • IPv6
    • What about IPv5?
    • Why IPv6?
    • IPv6
    • Identifying the IPv6 Prefix
    • Configuration
    • EUI-64
      • Configuration
    • Why invert the 7th bit?
    • Global Unicast Addresses
    • Unique Local Addresses
    • Link Local Addresses
    • Multicast Addresses
    • Anycast Addresses
    • Other IPv6 Addresses
    • Representation
    • Header
    • Solicited-Node Multicast Address
    • Neighbor Discovery Protocol
      • SLAAC
      • Duplicate Address Detection (DAD)
    • IPv6 Static Routing
    • Quiz
  • Access Control Lists
    • What are ACLs?
    • How ACLs work
    • Implicit Deny
    • ACL Types
    • Standard Numbered ACLs
    • Standard Named ACLs
    • Numbered ACLs With Subcommands
    • Resequencing ACLS
    • Extended ACLs
    • Quiz
  • Layer 2 Discovery Protocols
    • Introduction
    • Cisco Discovery Protocol
    • Link Layer Discovery Protocol
    • Quiz
  • Network Time Protocol
    • The importance of time
    • Manual Time Configuration
    • Network Time Protocol
    • Reference Clocks
    • NTP Hierarchy
    • NTP Configuration
    • NTP Server mode
    • Symmetric active mode
    • NTP Authentication
    • Quiz
  • Domain Name System
    • Purpose of DNS
    • DNS Cache
    • DNS in Cisco IOS
    • Quiz
  • Dynamic Host Configuration Protocol
    • Purpose of DHCP
    • DHCP Messages
    • Relay
    • DHCP Sever configuration in IOS
    • Quiz
  • Simple Network Management Protocol
    • SNMP
    • Versions
    • Messages
    • Configuration
    • Quiz
  • Syslog
    • Syslog
    • Message Format
    • Logging Locations
    • Configuration
    • Syslog vs SNMP
    • Quiz
  • Secure Shell
    • Page
    • Console Port Security
    • L2 Switch Management IP
    • Telnet
    • SSH
    • Quiz
  • FTP & TFTP
    • FTP and TFTP
    • Trivial File Transfer Protocol
    • File Transfer Protocol
    • FTP vs TFTP
    • IOS File Systems
    • Upgrading Cisco IOS
    • Quiz
  • Network Address Translation
    • Private IPv4 Addressess
    • Network Address Translation (NAT)
    • Static NAT
    • Configuration
    • Dynamic NAT
    • Configuration
    • PAT (NAT Overload)
    • Quiz
  • Quality of Service
    • IP Phones
    • Power over Ethernet (PoE)
    • Quality of Service (QoS)
    • Queuing
    • Classification
    • IP Precedence and DSCP
    • RFC 4954
    • Trust Boundaries
    • Queuing/Congestion Management
    • Shaping and Policing
    • Classification
    • Quiz
  • Security Fundamentals
    • Why Security?
    • Concepts
    • Denial-of-service Attack
    • Spoofing Attacks
    • Reflection/Amplification Attacks
    • Man-in-the-middle Attack
    • Reconnaissance Attacks
    • Malware
    • Social Engineering Attacks
    • Password-related attacks
    • Multi-factor Authentication
    • Digital certificates
    • Controlling and Monitoring Users with AAA
    • Security Program Elements
    • Quiz
  • Port Security
    • Port Security
    • Why Port Security?
    • Enabling Port Security
    • Violation Modes
    • Secure MAC Address Aging
    • Sticky Secure MAC Addresses
    • Quiz
  • DHCP Snooping
    • DHCP Snooping
    • DHCP Starvation
    • DHCP Poisoning (Man-in-the-Middle)
    • DHCP Messages
    • DHCP Snooping Operations
    • DHCP Snooping Rate-Limiting
    • DHCP Option 82 (Information Option)
    • Quiz
  • Dynamic ARP Inspection
    • Gratuitous ARP
    • DAI
    • ARP Poisoning (Man-in-the-Middle)
    • Operations
    • Configurations
    • Optional Checks
    • ARP ACLs
    • Quiz
  • LAN Architectures
    • Common Terminologies
    • Two-Tier Campus LAN Design
    • Three-Tier Campus LAN Design
    • Spine-Leaf Architecture
    • SOHO Networks
    • Quiz
  • WAN Architectures
    • WAN
    • Leased Lines
    • MPLS
    • Internet Connections
    • Redundant Internet Connections
    • Internet VPNs
      • Site-to-Site VPNs (IPsec)
      • Remote-Access VPNs
    • Quiz
  • Virtualization & Cloud
    • Server Hardware
    • Servers before Virtualization
    • Virtualization
    • Why Virtualization
    • Connecting VMs to the Network
    • Cloud Services
    • Five Essential Characteristics of Cloud
    • Three Service Models of Cloud
    • Four Deployment Models of Cloud
    • Benefits of Cloud Computing
    • Connecting to Cloud Resources
    • Quiz
Powered by GitBook
On this page
  1. Network Time Protocol

Symmetric active mode

PreviousNTP Server modeNextNTP Authentication

Last updated 1 year ago