Network Management

How hostname resolution works in IPAM

This guide describes how Hostname resolution is performed in IPAM.

First published date

10/12/2018 7:54 PM

Last published date

7/18/2021 4:13 PM

Overview

This article discusses how IPAM resolves hostname therefore acts as general guide to know if the DNS resolution is working

Product section

IP Address Manager

Cause

n/a

Resolution

Hostname Resolution in IPAM:

  • When a subnet is scanned, IPAM will try to ping an IP address from range.
  • When IP responds to a ping, IPAM will try to obtain a reverse record from the DNS server which is configured on the host OS.

Hostnames can come from different technologies. We are using a windows function, which is resolving IP address to hostname according to the current DNS server settings on the server. It may also get the hostname from other sources:

  • local hosts file
  • local netbios/wins cache
  • remote netbios/wins server query
  • local dns cache
  • remote dns server query
     

If IPAM is not displaying the hostname, verify that the IPAM server can resolve the hostname via Powershell

Launch Powershell on the IPAM server

Run the following commands:

$myhost = [System.Net.Dns]::GetHostEntry("10.0.0.1")

$myhost

Replace 10.0.0.1 with the IP Address in question

If the server is unable to resolve the hostname from the IP Address IPAM will also be unable to resolve the IP Address.

We also need to verify that the following record was created on DNS Server:

  • PTR record is required to resolve IP address (v4/v6) to hostname.
  • A record is required to resolve hostname into IP address.

In some cases, there is a need to create a Conditional Forwarder and set the "DNS Domain" using the reverse lookup format: ex. A.B.C.D reverse lookup format is D.C.B.A.domainname

Note: If using Neighbor Scanning, the hostname is not resolved.