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DNS Reverse Lookup Failed – How to resolve

by | Oct 30, 2021

Stuck with DNS Reverse Lookup Failed error? We can help you.

As part of our Server Management Services, we assist our customers with several cPanel queries.

Today, let us see how our Support techs proceed to resolve it.

How to resolve DNS Reverse Lookup Failed error?

DNS PTR records are used in reverse DNS lookups.

When a user attempts to reach a domain name in their browser, a DNS lookup occurs, matching the domain name to the IP address.

It is a query that starts with the IP address and looks up the domain name.

Typically, error might look as shown below:

Task ‘[email protected] ‘ Sending reported error: ‘The server responded: 550 This system is configured to reject mail from 999.999.999.999 [999.999.999.999] (DNS reverse lookup failed)’

Usually, you receive this error message when attempting to send mail through the Host Depot Email servers.

The Host Depot email servers use Reverse DNS lookups to verify the sender.

This helps with the amount of SPAM allowed in.

Today, let us see the simple steps followed by our Support Techs to resolve it.

1. Firstly, make sure the PTR records are indeed register (in their ‘own’ dns)

2. Then, create a conditional forwarder, stub zone or whatver you think is appropriate to make sure users using your dns in one domain to resolve records in a zone on the other.

Then, what you need to do is talk to the entity responsible for maintaining your public DNS.

This is normally your ISP. You need to have PTR record in public DNS.

This associates your public IP address with a FQDN.

The domain name portion of the FQDN need to match what your sending SMTP addresses contain.

[Stuck in between? We’d be glad to assist you]


In short, today we saw steps followed by our Support Techs resolve DNS Reverse Lookup Failed error.


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