What is Greylisting?

Calvin WongEveryone hates spam. (The email kind – not the canned meat). Spam is an especially pertinent issue for hosting customers. If you’re starting a new site and registered a new domain name, you’ll likely be bombarded with spam.

The reason is because your domain name registration information (your name, address, phone number, email address, etc.) is publicly available. Anyone can do a WHOIS search on your domain name and find your contact info. There are even services out there that will provide a list of all the newly registered domain names every day, making them easy targets for spammers.

Just do a WHOIS search on a domain, and you’ll find the owner’s email. For example, here’s the WHOIS information for discountasp.net. As you may guess, marketing@discountasp.net, which is listed as the contact email for our domain, gets a ton of spam.

One way to combat this is to get WHOIS Privacy when you register a new domain name. WHOIS Privacy will mask your real contact information by using the information of the registrar instead. It’s important to get WHOIS Privacy when you initially register a domain name. You can add Privacy later, but by then it’s already too late. Your email and contact info has already been published on one of those lists.

Greylisting is another way to combat spam. When an email network “greylists” messages, they do not accept the initial incoming message, but rather instruct the sending mail server to try delivery again later (which most servers will do every few minutes). The assumption being that spam servers will not attempt to send the message again, but legitimate servers will.

A large percentage of spam is sent from compromised home and business computers. Spammers typically send messages from large numbers of these machines, but each machine sends only small batches of mail, in order to avoid detection, and they will almost never try to re-send the mail when they receive the “try again” response.

Greylisting is a very effective anti-spam tool. Our tests show a decrease in spam of 80% to 90% when greylisting is implemented. But it can cause delivery delays. Those delays will vary, depending on the sending server, but are typically no more than a few minutes.

Previously, we had Greylisting enabled by default for all customers. But on October 17th, we decided to disable Greylisting by default for all new customers.

Why did we disable Greylisting?

New customers not familiar with Greylisting thought something was broken with our email service. They would sometimes experience delays of a couple of hours (the delay time depends on how the sending email server is set up to response to the re-send requests).

What can customers do?

You can re-enable Greylisting.

  1. Log in to Control Panel.
  2. Click the “SmarterMail Manager” link on the left side.
  3. Click the “SmarterMail Management Login as Primary Admin” link. You will be automatically logged in as the Primary Domain Administrator.
  4. Once in the SmarterMail interface, click the “Settings” link in the left navigation (it is an icon that looks like gears).
  5. Click to expand the “Domain Settings” folder.
  6. Click “Users”.
  7. Check the box next to the account you want to enable Greylisting for and click “Edit”.
  8. Uncheck the box next to “Disable Greylisting”.
  9. Click “Save”.
  10. Repeat steps 7-9 on all the accounts you want Greylisting disabled for.

You can Get SpamExperts

Our email service, SmarterMail, comes with spam filters. You can tweak those spam filters if you want, but most customers are wary of doing that. Set your filters too strong and you risk false-positives, possibly having legitimate emails go into your spam folder.

So, we partnered with SpamExperts to offer Inbox Filtering. SpamExperts works great! In fact, we adopted it for our own corporate use. The SpamExperts spam filter engine will scrub your incoming emails and take out spam, viruses, phishing and other malicious email messages. It works great out of the box, with no tweaking – set it and forget it.

Most other spam filtering services charge for each email account. If you have 20 email accounts/users, you have to pay for 20 of them. SpamExperts, on the other hand, just charges per domain. So you can have as many email accounts/users as you want and pay just $3.95/month!

If you do decide to leave Greylisting disabled, or if you just get too much spam, we highly recommend you get SpamExperts. We did, and we love it!

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