Email marketing requires knowledge of IP addresses. For some St. Louis marketing firms, this can prove challenging.

I recently got a call from a former prospect who is president of a company here in St. Louis. To save money, he chose not to work with MarketVolt, and instead installed a free email marketing application on his company’s servers. After a few months of sending email newsletters to a list of people who all had opted in, he began to notice a problem:

A certain internet service provider — a big one that serves many of the people on his list — was blocking delivery of the email newsletter. But worse yet, that internet service provider was blocking all emails sent from the company’s network.

Not only were the newsletters being blocked, but emails from the company president to individuals who host their email boxes with that internet service provider.

“What can I do?” he asked me.

I explained: Internet service providers — the companies that connect households and businesses to the internet and host their mailboxes — have spam filters that paint with a broad brush. Even if you comply with all of the anti-spam policies when you build your list, even if everyone on your list has given you explicit permission to contact you, there’s a good chance that the spam filter will eventually conclude that you’ve sent unsolicited commercial email.

A recipient might inadvertently push the “this is spam” button. The spam filter itself might misjudge the content of your email as “spammy.” There are countless things that could happen.

When the spam filter decides that you’re sending spam it will determine the network address of the computer from which you sent the offending email.

All computers connected to the internet have a set of four numbers, called an IP address. For example, MarketVolt sends email from several different computers, including one with the IP address

If a spam filter identifies a particular IP address as sending spam, it may block all email from that computer or it may even block email from all computers connected to the same network. For example, your commercial email may be sent from the ip address and your “office” emails from one individuals may be sent from The spam filter may block all mail from computers that are in the network

Why is this a problem? Well, it’s bad enough if you can’t get your email newsletters and product announcements past a spam filter. But it’s even worse if your company president or sales reps or customer support team can’t get individuals emails they send to one person through the filter.

That’s why we also urge clients to run their broadcast email systems on networks completely separate from the network on which they run their primary office email. If you follow this advice, you’ll still get those essential individual emails through even if your broadcast emails get blocked.

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