DNS Queries Failed to Reach or Return from the Server

The DNS queries failed to reach or return from the server insight can be accessed from the Global, Site, and Access Points context. This insight provides information about wireless entities that experience a higher than normal number of connection losses with the DNS Domain Name System. A DNS server functions as a phone book for the intranet and Internet users. It converts human-readable computer host names into IP addresses and IP addresses into host names. It stores several records for a domain name such as an address 'A' record, name server (NS), and mail exchanger (MX) records. The Address 'A' record is the most important record that is stored in a DNS server, because it provides the required IP address for a network peripheral or element. server. It identifies the loss patterns for DNS loss for each user. It is categorized under connectivity since the wireless clients are unable to reach the destination URL Uniform Resource Locator. URL is a global address used for locating web resources on the Internet.. This DNS queries failed to reach or return from the server insight displays the following information:

Insight Summary

The insight summary provides the following details:

  • Reason—Displays the possible causes for which the loss occurred.
  • Recommendation—Displays the possible recommendation against each loss to resolve the same.

Time Series Graph

The time series graph displays the number of connection loss that occurred during the selected time. You can hover your mouse over each bar graph to see the exact number of loss.

Cards

The cards vary based on the context that you access the insight from. Click one of the cards to view further details:

Table 1: Cards Context

Cards

Context

Loss

Global, Site

Site

Global

Server

Global, Site, Device

Access Point

Global, Site

Loss

This card displays what percentage of DNS loss events are explained by the entities found by the insight. The entities are listed in Site, Server, and Access Points cards. These entities are deemed as anomalies and enables users to investigate the actual root cause. A pattern is a specific combination of entities that is an indication of a root cause. For example, a pattern can be a combination of two sites which means that there are some issues specifically in those two sites only and there are no specific AP or a server that is contributing to the loss. By default, All is selected to show the summary of all the entities that got impacted along with the ones that form patterns in the loss trends. The data shown in each card, Site, Server and Access Point varies based on the loss pattern you select.

Site

Lists the number sites that are deemed as anomalies by the insight in the network. These sites either contain other entities such as, server or access points that experience higher number of losses, or these sites themselves are a pattern or root cause. Click the arrow to view the pictorial graph of the Most Impacted sites. Click the number displayed on the Site card to view a detailed description of the impacted sites:

  • Site—Name of the site and link to the specific insight at the site context.
  • Lost DNS Queries (%)—Total count and the percentage of the DNS packets that get lost in the network.
  • Total Queries—Sum of total number of successful DNS queries, total number of failed DNS queries, and total number of lost queries.

Server

Lists the number of servers that are deemed as anomalies by the insight in the network. These servers either have higher number of losses or combined with a list of APs that form patterns or the root cause. Click the arrow to view the pictorial graph of the Most Impacted servers. Click the Access Point drop-down list to view the following:

Success Rate—Graphical representation of the total failures, total losses, and total successful requests.

Click the number displayed on the Server card, to view a detailed description of the impacted servers:

  • Server IP—IP address of each server.
  • Lost DNS Queries (%)—Total count and the percentage of DNS packets that get lost in the network.
  • Total Queries—Sum of total number of successful DNS queries, total number of failed DNS queries, and total number of lost queries.

Access Point

Lists the number and details of APs that are deemed as anomalies by the insight in the network. These APs either have higher number of losses or combined with a list of servers that form patterns or the root cause. Click the arrow to view a pictorial graph of the Most Impacted access points.

Click the number displayed on the Access Point card, to view a detailed description of the impacted access points:

  • AP Name—Name of the access points and link to the specific insight at the AP context.
  • AP MACMAC Media Access Control. A MAC address is a unique identifier assigned to network interfaces for communications on a network. address of the AP and link to the specific insight at the AP context.
  • AP Serial—Serial number of the AP.
  • Lost DNS Queries (%)—Total count and the percentage of DNS packets that get lost in the network.
  • Total Queries—Sum of total number of successful DNS queries, total number of failed DNS queries, and total number of lost queries.
  • Model—Model number of each AP.
  • FW Version—Version of the firmware running on each AP.
  • Site—Name of the site where the AP resides.