
The following commands are useful in troubleshooting issues that involve the [Network Time Protocol (NTP)](/network-time-protocol-ntp).  

## Show commands

-   **show ntp association**
-   **show ntp association detail**
-   **show ntp status**

## Debug commands

-   **debug ntp packets**
-   **debug ntp validity**
-   **debug ntp sync**
-   **debug ntp events**


Links:

https://www.cisco.com/c/en/us/support/docs/ip/network-time-protocol-ntp/116161-trouble-ntp-00.html



NTP troubleshooting and debugging tools

Multicast PIM dense mode

Multicast PIM neighbors are stateless

Multicast PIM send-rp-announce-scope

Multicast PIM sparse mode Rendezvous Point (RP)

Multicast PIM sparse mode

Multicast PIM sparse-dense mode

Multicast PIM with multiple RPs

Multicast PIM with multiple mapping-agents

Multicast PIM-assert forwarder election

Multicast SPT and RPT

Multicast bidirectional PIM advantages

Multicast boundary filtering - filter auto RP

Multicast enabling Bidir in BSR mode

Multicast ip pim autorp listener

Multicast ip pim rp-address override

Multicast load splitting across equal-cost paths

Multicast local subnetwork address range

Multicast mapping IP to MAC addresses

Multicast mapping agent IGMP membership report

Multicast ping on a Nexus device

Multicast using Anycast RP with Auto-RP and BSR

Multicast

NAT - Translation Table

NAT - Twice NAT

NAT - Understanding debug nat detailed output

NAT - Virtual Interface (NVI)

NAT - add-route keyword

NAT - ports used for translation

NAT - translate address not directly connected to edge device

NAT Extendable on Cisco IOS

NAT Order of Operation

NAT address naming conventions

NAT and IPv6

NAT how port numbers are chosen when using PAT

NAT intra-VRF NAT

NAT port forwarding - specifying outside IP address

NAT prefix-length keyword on nat pool command

NAT vrf-aware

NBAR classifies only established sessions

NETCONF

NHRP - Authentication

NHRP - Destination Protocol Address

NHRP - Holding Time

NHRP - resolution redirect from hub

NHRP show ip nhrp flags

NHRP

NTP - securing with MD5 authentication and a Windows NTP server

NTP poll interval

NTP server and client and the master command

NTP versions 3 and 4

Native VLANs and untagged frames

NetFlow - Flow Samplers

NetFlow - applying to an SVI

NetFlow - what is a flow

NetFlow local cache size

NetFlow

Network - Discontiguous or Discontinuous

Network - Discontiguous

Network - Example of communication, encapsulation, and decapsulation, between hosts

Network - Flapping

Network - Layer 2 network

Network - Layer 3 network

Network - Monitoring multiple IPs of a single device with Observium

Network - Observium vs LibreNMS

Network - broadcast domain

Network - control plane

Network - data plane

Network Address Translation (NAT)

Network Collisions

Network Design - Spine and leaf architecture

Network Design - Switch oversubscription ratios

Network Design - Traffic Engineering

Network Design - on-premises and off-premises

Network Time Protocol (NTP)

Network design - confine VLANs to as few access switches as possible

Network planes

Networking - what is a socket

Networks - Overlay Network

Networks - Overlay Transport Virtualization (OTV)

Networks - Spanning Layer 2 networks across remote sites

Networks - Underlay Network

Next Generation Multicast Virtual Private Network (NG-MVPN)

Nexus - using vPC with HSRP

Nexus - what is vPC

Nexus lacp rate fast

Nexus

OSI Model

OSPF - Advertising point to multipoint networks

OSPF - Cost of summarized routes

OSPF - DR-BDR election per broadcast domain

OSPF - DR-BDR election priority of zero

OSPF - ECMP across two different areas

OSPF - Enabling authentication

OSPF - HMAC-SHA Extended Authentication

OSPF - Link State Updates (LSUs)

OSPF - MPLS SuperBackbone

OSPF - NBMA neighbors listen on 224.0.0.5

OSPF - NSSA P-bit

OSPF - Propagation of routes between areas