How can I increase deliverability of my mailing list

DISCLAIMER: If you plan on sending unsolicited emails or have bought an “opt-in” list somewhere, the below is not your guide. If any of your visitors are not expecting your emails, you are spamming. The below guide is meant for individuals and companies who are sending emails to a list of emails that expect their emails and wish to increase their deliverability rate. 

Arvixe does not allow sending of bulk emails (solicited or unsolicited) on our shared hosting accounts. The guide below would govern for VPS and Dedicated Customers.

Even if you have compiled the list of emails yourself by individually asking your customers, due to heavy restrictions placed on incoming email threasholds at larger providers, you can see your emails being deferred or completely bouned with 0% spam being identified/reported/detected. The below set of recommendations, ensures that you are doing everything in your power to increase the deliverability of your emails to the major email providers –

IP Reputation

Make sure your IP is clean to begin with. In most systems, unless you’ve made specific modifications, regardless of the IP of your website, the IP you are sending from is the main IP of the environment. You can use websites such as to identify whether the IP is already on any blacklists. Once you’ve identified that you have a clean IP, you need to start building your sending reputation. There are many organizations that attempt to track IP reputation and make the information publicly available such as –

In fact, some larger providers use this information so its important for you to track this as you venture into making sure your emails have the highest deliverability possible.

FBL Enrollment

FBL stands for feedback loop. FBL is a measure recently employed by some large providers to provide feedback to owners of IPs on what kind of feedback their customers are sending them in regards to their mailings. Many FBLs send examples of emails flagged as spam back to you. Others provide with statistics of how many emails were flagged automatically and manually vs the total # of emails sent to that provider from your IP. It is important to enroll into as many feedback loops as possible. It shows the provider that you are willing to work with them to reduce the number of emails considered spam by their visitors. Some FBLs by the larger providers are below –

AOL Feedback Loop:

AOL White list:

Hotmail SNDS:

Comcast Feed Back Loop:

United Online Feedback Loop:

Yahoo Feedback Loop:

SPF Record

SPF records are dns records which tell a mail receiving server who can send emails from your domain name. At a very basic level SPF is a way to combat email spoofing for your domain.  By adding a properly formatted SPF record, you are limiting the sources from which emails can be sent on behalf of your domain. Therefore, providers tend to place more trust on the emails sent from sources already verified by your SPF record. You can learn more about SPF and how to write a properly formatted SPF record at .

As an example, the SPF record for looks like this –

v=spf1 +a +mx +ip4: +ip4: -all

+a means include the IP address of the A record for (the ip address you get when you ping –

+mx means include the IP address of the MX record for (the ip address mails are delivered to for –

+ip4 allows you to add any other IP addresses that may send emails on behalf of your domains. This would include any subdomains you have setup on other servers that may have a forum/blog/etc setup that may be sending reminders on behalf of your domain

+a:IP allows you to specify a FQDN which the receiving party will automatically translate to the A record (the IP you get when you ping the FQDN)

-all outlines that you do not want to allow any other IPs to send emails on your behalf. If an IP that’s not authorized to send emails does send an email from your domain, it is often times automatically flagged as spam or bounced back.

Sending Pattern

Once you have setup everything above and have a handle on reviewing your reputation, you should start building it. Start by making sure you are actively using the mail server for regular emails that will definitely not be flagged as spam by your recipients such as bills, reminders, etc in small quantities (50-100 a day). Once you’ve done this for a week, you could start sending emails to parts of your mailing list. It is very important to try to spread the emails out as much as possible. And if possible, place a few seconds gap between the mailings so that if your reputation is still unknown to the receiver, they don’t defer your emails because too many emails are being sent in a short period of time (Yahoo is notorious for this).

Remember to always monitor your reputation and closely watch to make sure your emails are being delivered properly. If you are being deferred, which is often as a result of sending too many emails too quickly, slow down the emails until you have built up the proper reputation with that provider.

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