How to setup Reverse DNS and PTR records

Establish a proper reverse DNS zone to improve email delivery

To add another layer of validation to your sender reputation it is now advisable to create a reverse DNS record called a PTR and add to your DNS editor

DNS can be a strange topic, there does seem to be lot to know and just when you feel on top of things something can still pop up to surprise you, but it is now highly recommended to add this record

A simple explanation of reverse DNS is that it’s the exact opposite of DNS. Standard (aka forward) DNS maps a domain name to an IP address whereas reverse DNS maps an IP address to a domain name. The two are distinct and separate lookups however. Just because a forward lookup of resolves to doesn’t mean that a reverse lookup of will resolve to

Why it’s needed

The most common reason for establishing a reverse DNS is for outbound e-mail servers. Since a reverse DNS record adds further tracing to the origin of an e-mail, it also adds credibility to the e-mail server itself. For that reason, some incoming mail servers now will not even consider accepting a message from an IP address which does not identify itself with a PTR record in a reverse DNS zone.

How to do it

A very important thing to note, you must create the reverse DNS zone on the authoritative DNS nameserver for the main IP address of your server. You can find out which nameserver is the authoritative server by entering the IP address you’re trying to configure into the DIG Web Interface. If the Reverse response is not provided by your nameserver, you’ll need to contact your hosting provider to help you set a PTR record. You should be able to accomplish that be emailing their support team and letting them know you’d like a PTR record set for the IP address X.X.X.X resolving to

If you are in control of the authoritative nameserver, the first step is to create a reverse DNS zone. The hostname for the zone must be in a very specific format. It starts with a portion of your IP address written backward followed by

If for example your IP address is, you start by dropping the final octet (last set of numbers) to give you 192.168.0

Next, you need to reverse that fragment of the IP address giving you: 0.168.192

Finally, append leaving you with the completed reverse zone domain of:

Create the PTR Record

Now that you’ve created your zone file you can create the PTR record.

Add a new PTR record and for the name, enter the final digit of the IP address that you’re setting up the reverse record for. In our example, 100. For the Canonical Hostname, enter the domain name you’d like the IP address to resolve to, for instance

After you’ve saved your zone file, allow some time for the change to propagate before validating the new reverse DNS record.

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Marketers guide to Mastering the art of inboxing

Email deliverability has never been more challenging. Email service providers (ESPs) and Internet service providers (ISPs) are closely monitoring signs of spam mailings and potentially malicious activities. In 2014, 60% of emails were reported as spam, according to Symantec.1

Reputable senders might think they have nothing to fear, but if they don't follow proper email etiquette, their messages may never reach their intended target. Senders can fall victim to blacklists and poor sender scores if they're not careful.

So how do senders ensure their emails reach inboxes? This checklist provides five key steps senders can take to improve their email performance.


Monitor bounce notifications.

Email bounces and spam complaints are major red flags for ISPs. Senders can improve their mailing reputation by monitoring bounce notifications. For example, many email services provide feedback loops that tell the sender when a recipient classifies the message as spam. Senders who continually send emails to bad addresses or don't heed their email service provider's feedback will have their emails filtered or dropped.

Remove inactive email addresses. Senders should remove other addresses from recipients who aren't responding to or interacting with their emails after 90 days. ISPs take interaction, such as opens or clicks, as a positive sign, which improves the sender's reputation.

Have an "unsubscribe" feature. Senders must have an unsubscribe function. They should include a link or form on their website where recipients can "unsubscribe" from their list and an opt-out link in every email they deliver. While an unsubscribe, option is a requirement under the CAN-SPAM Act, it also discourages recipients from filing spam complaints, which can damage a sender's reputation.

Offer a double opt-in subscription. This means the sender is validating the email entered on its website twice – first by having the user enter the address on the site and then asking recipients to confirm their subscription through a confirmation email.


Adhere to authentication protocols. ESPs will assume a sender is spamming and will filter or drop the sender's email if the emails are not properly authenticated. The common types of authentication are SPF, DKIM and DMARC. These authentication protocols work for both one-to-one email or bulk emails.


Monitor email scores. Email reputation is similar to personal credit scores. A poor email track record or no track record at all may prompt an ESP to filter a sender's message. It also may result in a poor sender score. Sender scores range from 0 to 100. Sender scores under 70 typically end up in spam folders. Senders can monitor their reputation scores by using monitoring tools, such MX Toolbox or

 Use a private IP address. One of the culprits of a poor email score or possible "blacklisting" by an ISP is the use of an IP address for malicious activities. Some ESPs require senders to share an IP address with other users. This can have a negative impact on a sender's score if the other user is sending spam.​

ESPs that require shared IP addresses should have strong spam monitoring features. Otherwise, senders should opt for a private IP address.


Keep images to a minimum. Too many images and text links trigger spam flags at ESPs.

Send multipart emails using both text and HTML or text only. Sending HTML-only email is not well received by ESPs.

Also, ESPs generally block images by default, so HTML only will not look very good unless users are proactive about enabling images.

Avoid promotional text. Gimmicky, promotional text, such as "Buy Now!" or "Free!" are major spam flags. Also avoid using all caps in text and exclamation marks.

Personalize emails. The content should reflect the recipient's specific interests or usage patterns. Also address the recipient by name.

Always identify who is sending the email. Make sure each email has a valid reply-to address and an unsubscribe link in the body.


Consider a pool of IPs. ESPs have send limits for each IP address. High-volume senders (over 50,000 emails per week) should consider using a pool of IPs.

Consider a shared IP for lower-volume emails. Organizations that send less than 5,000 emails per week should consider a shared IP. Many ESPs won't acknowledge a sender's reputation if their volume is too low. A shared IP can help boost perceived sending volume.

Use separate IPs for bulk and transactional emails. Time-sensitive transactional emails may get queued behind a large batch of bulk marketing emails. In addition, the reputation of transactional emails can be negatively impacted by bulk marketing emails.


Senders who keep a close eye on their email performance can take corrective actions before they waste valuable time and resources on unsuccessful email deliveries.

By taking a more active role in their delivery efforts, senders can boost their reputation scores and avoid email death traps, such as spam filters or blacklists.

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Marketers Guide to getting better delivery to the Outlook inbox

Launched in 1996 as Hotmail, Microsoft’s email service was one of the first web based email services. In fact, the name original name Hotmail is a play on HTML, or HoTMaiL.

In 2013, Microsoft rebranded its service as to align with its desktop offering, Microsoft Outlook. Currently has over 400 million active users and is available in more than 106 languages, making it one of the leading global mailbox providers.

In this post, we will walk through’s spam filtering systems, features, support tools, and whitelisting services.

 Spam Filtering

Exchange Online Protection

Exchange Online Protection (EOP) is a cloud based filtering system that protects users against spam and malware.

Microsoft is currently in the process of merging EOP and SmartScreen filters to increase the accuracy of their filtering.

SmartScreen utilizes Microsoft’s patented SmartScreen spam filtering technology. This technology uses a machine learning approach to help protect users’ inboxes from junk email. SmartScreen technology learns from known spam and phishing threats, as well as from’s customers who have chosen to participate in the Sender Reputation Data network.

Sender Reputation Data

Like many mailbox providers, factors volume, spam complaints, and spam traps into their filtering.

However, the company also relies heavily on their Sender Reputation Data (SRD) network for their filtering decisions.

Microsoft refers to their SRD program as the Spam Fighters Program. Along with other sources of reputation data—such as the Junk eMail Reporting Program (JMRP)—SRD helps to train and improve the way their filtering classifies messages based on email content and sender reputation.

The goal of the SRD program is to derive a better picture of a sender’s reputation by using feedback from trusted voters.

Participants in the SRD program are selected from active users at random from over 200 countries and no one can volunteer for the program.

To get feedback, Microsoft resends copies of emails that members of their SRD panel received in the past 24 hours.

 The message comes from Microsoft Spam Fighters and the sender’s original subject line is appended with “[Microsoft Spam Fighters] Junk or Not?”. In the SRD email body, subscribers vote on whether they think the email is junk or not junk. A junk vote is negative feedback and a not junk vote is positive.

SRD feedback is more reliable than feedback derived from complaints, because while senders can lower their overall complaint rate by sending more volume, they cannot artificially lower SRD rates.

 Postmaster Services

Smart Network Data Services (SNDS)

SNDS is a free service that provides aggregate data on email volume, subscriber complaints, spam traps, and more.

SNDS uses a colour coded system which indicates trustworthiness:

• Green indicates a positive sending reputation, and higher inbox placement rates to are likely.

• Yellow signals reputation issues starting to surface, and a mix of inbox and junk folder placement is likely.

• Red means that there are serious underlying reputation issues, which are causing most, if not all, emails sent to land in the junk folder.

Result Example Verdict percentage

Green Spam < 10%

Yellow 10% < spam < 90%

Red Spam > 90%

Junk Mail Reporting Program (JMRP) offers their Junk eMail Reporting Program (JMRP) as a free feedback loop service to anyone who wants to sign up. JMRP reports are generated as the result of spam complaints originating from users only, and does not include SRD participants.

The headers of the received complaint will also indicate if the subscriber marked it as junk or phishing. Emails marked as phishing indicate that the sending identity wasn’t known, or perhaps something in the content looked suspicious.

Support offers self-help and escalation paths for senders having deliverability issues. Senders are asked to ensure they are following all best practices on the troubleshooting page.

 If senders are certain they are following best practices, they can enter a ticket to the postmaster team.

 Email Infrastructure asks that senders’ mail infrastructure comply with the following:

• SPF: asks all senders to publish an SPF record for the return-path.

• DKIM: also conducts Domain Keys Identified Mail (DKIM) checks on inbound email.

• DMARC: recommends senders publish a DMARC record to reject or quarantine mail sent from illegitimate senders.

Partners does not currently have any partners.

 Whitelists and Prioritized Delivery does not maintain an internal proprietary whitelist. They do however participate in Return Path’s Certification Program.

 Return Path Certification provides preferential treatment to accredited senders, allowing them to bypass certain filters to reach the inbox. Those accepted into the Certification program are required to maintain the standards set by Return Path and its participating partners.

 User Interface

The interface makes it easy to sort through personal mail, social notifications, graymail, and more.

Message Features

Scheduled clean-up

Scheduled clean-up allows users to set rules to automatically delete old emails and only keep the latest from a sender.

For most senders, this isn’t an issue. But for senders that send multiple times a day, a different from: addresses for each mail stream may be needed.

Categorization’s categorization can be used as Quick Views for users, which is a similar concept to Gmail’s tabbed inbox.

Archive’s archive feature moves all messages to the Archive folder keeping the main inbox clutter free.

Delete all from

The “delete all from” functionality allows users to easily delete all email from a sender based on the from: address.

This is good news for any business that has had to deal with users using the “Report Junk” button in the past.

Focused Inbox’s new feature separates the emails receive into two inboxes. Emails users frequently interact with arrives in the “focused inbox” with the rest delivered to the “other inbox.”

Unsubscribe Methods

Like Gmail, also takes advantage of the List-Unsubscribe header. There are two ways subscribers access the ListUnsubscribe functionality: through the “too many newsletters” footer or the “sweep” feature.

Too many newsletters? Unsubscribe.

As shown below, displays the “Too many newsletters?” verbiage under the email.

It is important to note that this verbiage is not part of the email. Rather, it’s part of’s user interface. When the hyperlink is clicked, the following popup will be displayed if a List-Unsubscribe header is present.

If the List-Unsubscribe header is not included, the following popup will be displayed:

Sweep unsubscribe

Using’s Sweep feature, users can select one of several actions for a given email, including unsubscribe.

If you want to send emails that pass all the tests required to get more emails delivered to the inbox not the spam box look at our flagship autoresponder, InboxingPro

Send unlimited emails, upload unlimited subscribers and create unlimited campaigns with a lifetime license with no monthly fees

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