Coder Scoop Inc

The Scoop on Email

Getting Your Emails Into The Inbox Is No Small Task

Email is still the top medium for keeping in touch with your users and customers. Thanks to the huge number of junk emails that are being filtered out by email service providers, getting your legitimate messages into  inboxes these days is a big challenge. Understanding those challenges and acting upon them should be part of your overall marketing strategy. Read on, and chances are, your eyes will be opened.

1. Sender Reputation

The IP address your message is being sent from has the largest impact on whether your message will wind-up in the inbox or in spam, or even being rejected or deleted outright.

Cold IP addresses, that is nodes that have not been used enough or at all to send email, are deemed untrustworthy. A high percentage of spam emails come through “zero reputation” IP addresses, just so you understand that dynamic. Email from such IPs will tend to wind-up in recipients’ bulk or spam folder or being severely delayed.

IP addresses that have been previously associated with messages that recipients declared as spam will have their “sender score” impacted and if enough people made that assessment, the messages could wind-up being blocked or silently rejected (they’re accepted but deleted, not delivered).

If an IP was reported to any blacklist as the source of spam, a large number of receiving mail servers will block any connection attempt from that IP, many of them dragging the connection on purpose before timing out, which can wreak havoc on spammers but often winds-up punishing legitimate senders.

What applies to sender IPs also applies to sender addresses. So if has been associated with spam or is blacklisted, any message from it will be treated with disdain!

By sender address, we mean the email used in the dialog between mail servers, which may differ from the emails used in message headers, such as in the From and Reply-To headers..

2.  Sender Identifying Headers

Your server-sent messages should always have the headers which can be verified via a DNS query to ascertain that the message sender info isn’t forged. These include DKIM, SPF, and DMARC. If any of these are missing, the odds are that your emails will wind-up in spam. Their presence, however, does not guarantee delivery to the inbox.

3.  Message Subject and Content

A large number of receiving mail servers will pass your message’s subject and content through a “Bayesian” filter which will score your message’s probability of being spam based on the words and expressions contained within. For instance, words like “ultimate” and “free” score heavily as spammy words. 

4. Links

Any links within your message that have a domain that’s different from the domain you’re sending from will be treated suspiciously. So, for example, if your message is from and your message body contains a link to, this will score poorly. Even worse are links that redirect, such as tracking links.

5. Real Sender address

A number of email services will be set-up to actually check if the sender address actually exists, by connecting to a mail server (MX) listed for its domain via a DNS lookup. If the server on the other end answers that the address doesn’t exist or rejects the request, or if there’s no connection made, the messages coming from that address will very likely be rejected.