How to Avoid Spam Filters with
Proper Email Delivery and a Good Email Reputation!

Proper DNS configuration avoids the first line of ISP spam filters

Autoresponders, broadcast services, from my database on my computer or from a script on my web server. Does it really make any difference how I send email?

Of course the way you send email matters. It probably affects the delivery rate more than any other aspect than anything else.

Lets start by looking at how an ISP looks at your incoming email.

Your IP Address Is Your From Address To An ISP

When you decide to open an email it is because you recognize the from name and to some extent trust the sender.

When an ISP looks at your email they look at the IP address of the email server it originated from. They do this thru what powers the internet and that is the DNS system.

We see the front end to the Domain Name System (DNS) when we type an address in the browser address bar. This is just the user interface for linking to IP addresses of the servers where our sites and files reside.

All ISPs that accept incoming email use a reverse lookup tool based
on the DNS database. They use the name of the server that the email came from and make sure that your domain is actually hosted on that server. The most important part of reverse lookup is that the ISP also checks to see that the email server that the mail is coming from is associated with your hosting server.

Or if you are on a shared it’s server the name of the hosted server.

You can try an example of how a reverse lookup system works here:
http://www.dnsstuff.com/

I am referring to the “Reverse DNS Lookup” form.

Enter your domain name and your IP address is returned.

Enter your IP address and your domain is returned.

Next use the “DNSreport” form to see if there are any problems with how DNS associates your mail servers with your domain. Pay particular attention to the “MX record” and “SPF record” entries in the returned report. Don’t worry if the entries show a warning, we will cover this in the second half of this book.

You can use this same lookup tool to check your email server domain (or lack of) but you will need the IP address of your email sever from the header of an email you received from yourself providing you are connecting to your server thru SMTP or from your autoresponder, script or broadcast service.

Open the email from your autoresponder or newsletter and click on properties or view source depending on your mail client.

This should open the full email in a text editor of some type.

The header information is at the top and this is the instructions to your mail client on how to display the message and a record of where the message came from.

There will be a number of entries that say “Received from” reverse order of how they were received. Each entry is a hop or server that your email went thru. The last entry contains your email server IP address. It will also have the oldest date entry on it.

It should be something like 59.39.23.10

That is the server the message was sent from.

This cannot be faked like a return address.

This is what an ISP looks at before it passes on your message.

You can also call your autoresponder service and ask for the IP address of your email server(s).

Some articles will say that after a reverse lookup at the ISP level that if the returned sending domain does not match the from email address that it will be deleted or filtered.

Most of my research has shown that this in just not true. This may well change in the future but for now you are ok.

However, your email’s reverse IP lookup must resolve to a domain.

If a reverse lookup returns a “no domain associated” then it will bounce, be deleted or filtered. That is absolutely true at this time.

What Reverse Lookup Means to You

Here are the questions that a receiving mail server is trying to answer about your email…

Is the IP Address a Dynamic IP Address

This is the first part of reverse look up that determines filter triggering, if you are sending from a dynamic IP address. This is also currently that main reason for reverse lookups.

Your own ISP assigns a temporary IP address to your home computer so you can connect to the Internet. This type of IP address is defined as a “dynamic IP.”

Every time you logon to your Internet connection your ISP establishes a connection to you thru an IP address it has available at that time. Hence, it changes every time. Broadband connections usually stay the same for a few months but will eventually change. Both of these types are deemed as dynamic because they are dynamically assigned on demand. Also they do not resolve to a host name (your domain).

Sending any volume of mail from a dynamic IP address will immediately trigger a filter. The current train of thought is that most spam is currently being sent from home based PCs with broadband connections infected with a virus usually referred to as “zombie machines.”

This is why email to lists should not be sent from local databases on your home machine. Some email newsletter software like MailLoop still attempts to do this but it is a thing of the past. Do not use MailLoop.

Is This Email From a Known Source of Spam?

First of course is whether or not the IP address of the mail server is a known source of spam. This may depend on a number of things including how many spam complaints the server sending your emails has received at the ISP in question, online blacklists and ISP blacklists ISPs maintain themselves. This is what they do with lists of user spam complaints that come from the “This Is Spam” button.

This can also be a problem for shared servers like most of us use. If other site hosted on our hosted server send spam then the whole server and all the sites hosted on it will be banned.

Is This a New Server That Has Never Sent Us Mail Before?

Hotmail and Spamcop are notorious for this. You set up a new server, send email to your list and you get banned for a time. New sources of mail get sandboxed for a time in some cases to see if it is a new server set up be a spammer. It sucks but it happens.

Is This Email Server Is An Open Relay

An open relay is a vulnerable unsecured email server that can be easily used to send third party spam. If your mail server is a known open relay your emails will be deleted by all major ISPs. Not usually a problem in today’s shared hosting world.

Solutions

The solutions to reverse lookup problems are simple. Don’t send email from your home computer and don’t send email from a crappy $3.95 a month shared hosting server. If you are going to send email yourself at least get a decent host where no more than 50 sites per server are allowed. Better yet a semi dedicated server

20% of legitimate email is deleted or filtered by mistake! - source Lyris.com Name: Email:

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