What are PTR Records and Why are They Important?
Mastering the Art of Configuring PTR Records: A Guide to Effective Email Deliverability with Reverse DNS and Lookup
PTR records, reverse DNS, and lookup are methods you can use to verify that the sender and the IP address from which messages are being sent match. A telephone directory for the Internet would be the DNS (Domain Name System), which maintains a vast amount of data on millions of registered domains.
A DNS lookup is necessary to access a specific domain's (virtual) pages. You can only do this with browsers immediately following the entry of an email address. By using a DNS lookup, they can quickly ascertain that an address like https://filzone.io represents the IP address 184.108.40.206. An "A Record" designates this outcome.
A server can obtain a domain or hostname from an IP address by running a DNS lookup in reverse. Read on to learn how to configure PTR records in DNS records.
How do I set up PTR records in DNS records?
When adding a PTR record, take your web hosting provider into account. Additionally, a reverse DNS zone must be set up. A zone in DNS is a unique area of a domain namespace.
If this is the situation, you can say that the DNS for your domain has reached a forward-confirmed reverse DNS (FCrDNS).
Are Multiple PTR Records Permissible?
Contrary to multiple PTR records for the same IP address, a PTR record can only point to one hostname. If this IP address is not resolved for each of these domains, you won't have a match for the PTR records.
How can I Determine Whether my PTR Records are Set up Properly?
Either you manually check PTR records using online tools, or you use a computer to query the domain name servers.
To manually verify PTR records, use the dig and nslookup commands on Windows, Linux, or macOS. The following commands would sequentially query DNS servers for the domain mentioned above.
How to check PTR records with the dig command?
- Enter the command
dig PTR <server-ip-address>.in-addr.arpa.The PTR record should be shown.
How to check PTR records with the nslookup command?
- Enter the command
nslookup -debug <server-ip-address>. Under the "ANSWERS" and "Non-authoritative answer" sections, it will be clear that the PTR record is present.
How do I Test Email Deliverability After Configuring PTR Records?
Setting up PTR records doesn't guarantee that recipients will receive your emails in their inboxes. Yes, it's a good "anti-spam" measure, but it's not the only one. But you will need to test deliverability.
QAs used to create a lot of fictitious emails and send test messages to see if emails would arrive in recipients' inboxes, but this method is now obsolete.
Most developers and quality assurance professionals now rely on secure testing tools like mailslurp Email Sandbox. It helps to examine spam scores and blacklists using these test email-trapping features.
As an alternative, you can use online resources like MxToolbox, NsLookup, whatsmydns, and others to check PTR records. You only need to enter your IP address or domain address to do this. You’ll see the results immediately.
To find information about PTR with MxTookbox, you must perform a reverse lookup; in contrast, NsLookup has a PTR record search option. You can select which DNS server you want to query with Whatsmydns, making it a little more sophisticated.