By Tech Editor Jill Keogh

At the Email Deliverability Summit in San Francisco last month, I heard with my very own ears from ISPs that their filtering accuracy improves when the sending email list host dedicates their IP addresses by client.

The exact quote escapes me but “it helps greatly if the email list host incorporates granular IP differentiation” is pretty close.

What does this mean in English, and what should you do about it?

Every outbound email sent in the world contains a number (example: 10.11.12.13) automatically embedded in the email header that tells the recipient's system (such as AOL, an ISP, or a corporate IT department) where the email came from. This is the IP address.

The IP address is the only true way that an email receiving system can know where messages are coming from. Everything else (such as your "from") can be faked, but not the IP address. Think of it as your home mailing address – there’s only one house in the world with that exact address.

So, IP addresses are invaluable for blacklists and ISPs who want to stop unwanted junk mail. They simply look for the IP address of a junk mail sender and block all mail that comes from that address.

This can cause a huge problem for you if you share an IP address with another mailer. If they get blacklisted or blocked, so does your email. (In fact it's happened to our parent company MarketingSherpa on three occasions, one of which was with AOL.)

Broadcast email services generally buy these numeric IP addresses in blocks of 1,000. So it's not horribly unreasonable to expect them to give you your own IP address.

Currently most broadcast firms handle IP addresses in one of four ways:

#1. Safest for you: They assign each client their own IP address, and they refuse to accept accounts from high risk mailers whose activities might get the broadcaster's entire range (all 1,000 or more) of IP addresses blacklisted.

#2. Pretty good for you: They make clients share IP addresses, but group them according to how risky that client's permission- level and content-type is. They also refuse to take truly high- risk clients (people who send opt-out, etc.)

#3. Worrisome for you: They employ a combination of sharing and dedication. They reserve some IP addresses only for clients with low risk. Then they group the rest of their clients (as well as any messages sent to your non-confirmed names) into sharing a range of addresses. They do accept some higher-risk accounts.

#4. Probably bad news for you: All client's IP addresses are rotated (you have a “moving” IP.) This may help the broadcast firm for many reasons including handling the distribution load, but if you send an email now from an IP address that sent junk 30 minutes ago; your whole email broadcast could be blocked. Avoid these vendors unless they prove they only work with customers whose permission requirements are pure as snow.

Given the choice, you want your own IP address because:

o You don’t share the reputation of other emailers using the same IP address. If they send junk, you’re punished too.

o Broadcast firms that are known to allow sharing of their IP addresses among their clients are more likely to have their entire 1,000+ range of IPs blocked by ISPs and challenge- response systems.

o Many receivers only whitelist by IP address -- so if you want to be whitelisted (especially if you are sending to corporate America) you need a dedicated IP address.

Why doesn’t every broadcast firm dedicate IPs for clients then?

Because it requires an investment in hardware and software, and that isn’t cheap. Before the filters became what they are today, the technology your broadcast firm uses was fine. But now they need to invest in upgrades.

Does this mean you should automatically switch firms because yours doesn’t provide you a dedicated IP? No. But you need to know the risks and how they are managing your brand.

You may not need to be concerned at all if you are working with broadcast firm with very high service levels, and a great reputation on the ISP-side, that only takes clients that meet specific permission requirements, and refuses all others.

However, if you weren't asked any questions about your permission level when you signed up, and your contract doesn't specify anything, then you're almost certainly sharing the service with junk mailers who may get your mailing blocked. This is especially true of self-service ASPs that anyone can sign up for online without going through an account rep first.

Here's what you should ask your broadcast firm today:

Do I have a dedicated IP address? Yes or no?

If their answer is "Yes", then ask:

-> Am I sharing it with anyone else? If so, why? (no techie reasons please, practical business reasons only.) How many other clients are in the range? How do you determine exactly which clients share my IP?

-> How do I know my IP is dedicated? What’s the IP address? (Write it down.) Will you ever reassign a new IP to me? How will I know? Was there a contract that included a guaranteed dedicated IP?

If their answer is "No", then ask:

-> Can I get a dedicated IP address? Will it be available in the near future? (Many broadcast firms are updating technology constantly.)

-> How much does it cost to get my own IP address? Expect to pay a set up fee by some estimates ranging from a couple hundred to a couple thousand dollars. Or, you may not have a set up fee and your monthly fee may go up.

-> How do you handle complaints against your IP addresses? Test their complaint system by discreetly emailing their abuse@listhost.com email address. Say “Hi! I’m your customer (or potential customer) and I wanted to see how this abuse complaint system works. Please respond as soon as you receive this!” If you don’t get a response in a reasonable time frame or, worse, the abuse email bounces back… Run in the other direction as fast as you can.

-> How do I know I’m not swimming in a swamp with spammers? Beware the response that comes with promises that “you aren’t” or reduces it to a silly question because after all, their list host’s business would go under if they were junk mailing. That doesn’t cut it today. Why are they not investing in this option is the question back.

Now you know the facts to make a good business decision and hopefully you have new insight as to why you are paying more (or less) than other options.

Acknowledgements:

Steve Atkins and Laura Tessmer at http://www.word-to-the-wise.com,

Brian Livingston at http://www.brianlivingston.com

Jordan, Mike and Dan at http://www.subscribermail.com for tech info that helped with this article.