NSX Edge Unable to Resolve Hostnames

Products

• VMware NSX

Issue/Introduction

Symptoms:
NSX Edge (ESG) cannot resolve FQDNs for Syslog or IPsec VPN.

Environment

VMware NSX for vSphere 6.3.x
VMware NSX for vSphere 6.4.x

Cause

When you configure edge DNS settings from the UI, you are only configuring the DNS forwarder and DNS queries received on Edge interfaces. 

Sometimes, though the edge sends its own DNS queries, for instance, when using the FQDN for an IPsec Peer.

In order to for the edge to be able to resolve its own DNS queries, you need to configure DNS clients for the Edge via the API call below:

Resolution

Changing DNS settings of an Edge

API to update the dns settings (primary/secondary) of an Edge:

PUT  https://NSX-Manager/api/4.0/edges/{edgeId}/dnsclient

Body:

<dnsClient>
    <primaryDns>IP_address</primaryDns>
    <secondaryDns>IP_address</secondaryDns>
</dnsClient>

HTTP Result Codes:
204 NO CONTENT