Unsolicited Bulk Email (UBE) or "spam" is one of the most common annoyances on the Internet today. In a National Technology Readiness Survey, it is estimated that the average user spends 3 minutes a day filtering spam. We take spam very seriously and have several measures in place to help prevent the receipt of spam. Even with our extensive Spam Prevention measures, spammers are constantly coming up with new ways to fool spam filters. This article details all of the measures we already have in place to protect you from spam, but also provides additional details on how you can further reduce the influx of spam to your mailbox.

How can I prevent my mailboxes from receiving spam?

As the end user, you are able to take measures yourself to prevent your inboxes from receiving spam. These include both preventive measures and means to manually filter your incoming mail.

1) Do not give out your email address to any untrusted sources

The web is full of people looking to send you product information and special offers or turn around and sell your email address to others. Always be aware of who you are giving your email address to. Believe it or not, buying and selling valid email addresses is big business and by giving your address to the wrong people, you can quickly find yourself with an influx of spam email. As an example, if you have an email address that is a vital business contact, it's probably not a good idea to use this same email address when signing up for a "Win a Free Car" sweepstakes you see on a website you're visiting. If you absolutely have to be entered in that drawing, think about creating a brand new email address. Or if checking two email addresses is too much work, setup a new email forwarder for an email address and forward it. In the event that email forwarder starts receiving spam, you can simply delete it and your original address will remain unknown. With our hosting plans, you have the ability to create unlimited email addresses and unlimited forwarders. Don't be afraid to use them.

2) Don't list your email address in plaintext on your website

Automated crawlers can scan the source of a webpage and pull out any email addresses it finds on it. If you list your email address in plaintext on your website, an automated spam bot can read it and add you to its spam sending list. If you want to list your email address, create an image of it and provide the image on your site. Spam bots cannot interpret an image's data and won't be able to read the address displayed. Alternatively, you could list your email in text on your site as :

myaddress [at] mydomain [dot] com

This is another common way of stopping the most basic spam bots. Basic spam bots are trained only to look for myaddress @ mydomain . com. By replacing the @ and the . with textual representation, it prevents the spam bot from getting a match to an email address format.

3) Lock down any contact forms

If you have contact forms on your site, make sure they are locked down. Ensure that your form has a referrer check on it so that only submissions from your site are accepted. It is also a good idea to include a captcha on your form. Captchas are images which require the interpretation of a human in order to proceed. These often include skewed text or pictures which are unidentifiable by automated bots. By preventing automated bots from filling out your contact forms on your site, you prevent them from sending you spam. Of course, this only applies to preventing spam from being received by those email addresses which are configured to receive form submissions.

4) Email Filters

Within your cPanel, you have the ability to create specific email filter rules for routing email. Email filters can filter by sender, body content, subjects, and many more criteria. For full details on adding email filters, please see our demo in our Knowledgebase:

Creating an Email Filter

Even with these measures, there is bound to be spam which continues to arrive in your inbox. Your service with us includes several features which help to further reduce spam receipt. The most notable of these is the Barracuda Spam Firewall included at the end. Of all the spam tools available to you, the Barracuda Spam Firewall is the most effective and is often the end-all solution to spam. If all else fails and you continue to receive spam, we highly recommend considering employing use of the Barracuda Spam Firewall.

How does SPRHost Network protect me from spam?

1) Disabling catchall email addresses

By default, we disable catchall email addresses across all of our servers. A catchall email address allows you to route email sent to *anything*@yourdomain.com to given email address. Just as the name implies, it "catches all" unrouted mail. This often helps if your users commonly mistype some of the email addresses you use to receive email. However, a catchall email address usually does more harm than good. Automated spam bots will often attempt to send email to a dictionary of addresses at your domain. In explanation, they start with the names beginning with the letter 'a' and work down to 'z' looking for valid email addresses ( amanda @ yourdomain . com, andy @ yourdomain . com ... zoe @ yourdomain . com, etc.) To prevent you from receiving all of this spam email, we disable catchall email addresses.

In addition to this, we also block dictionary attacks by dropping and rate limiting hosts that have an excessive number of failed recipients. During a dictionary attack, the spam bots often use the bouncebacks to determine which email addresses actually received their mail and which bounced it. They can then use this information to send spam directly to the valid accounts in the future. By rate limiting these hosts after repeat failures, we prevent them from even attempting to send your account spam.

2) Barracuda Blacklist

The Barracuda blacklist is one of the most widely used and expertly maintained blacklists in the world. Barracuda maintains a list of all IP addresses which are known spam senders. Each time a message is received on our server, the sending IP is checked against the Barracuda blacklist and denied if a match is found. 75% of spam email can be effectively rejected just by a blacklist lookup on the sending IP address. The advantage of this spam prevention measure is that it has a high degree of accuracy and a low false-positive rate.

3) Sender Verification

It is common practice for spammers to forge the email address which they are claiming is sending the email to you. Each time your server with us receives a piece of email, it first sends a Sender Verification Callout to the server which sent the email. If they sending server does not confirm that the email account which claims to have sent the email is in fact a valid sender, our mail server rejects the message. This is basically our server asking the sending server "Is the email address which sent this email a real email address?".

4) Barracuda Spam Firewall

The Barracuda Spam Firewall is an external hardware appliance used specifically to filter email before it is delivered to your mailbox. Used by goverment agencies, ivy-league universities, and fortune 500 companies, the Barracuda Spam Firewall includes 12 layers of defense against the spam threat. All of our new Enterprise 2.0 Web Hosting Plans come with a free Barracuda Spam Firewall account. More details on our Enterprise 2.0 plans can be found here:

If you would like to upgrade to the Enterprise 2.0 plan, please post a ticket with our Sales Department and they will be happy to assist you.

If you do not wish to upgrade to our Enterprise 2.0 plan, but would still like to make use of the Barracuda Spam Firewall we also offer a la carte upgrades.

We also have options available to our Resellers who wish to offer Barracuda accounts to their clients.

Again, please contact Sales and Billing for full details on our Reseller packs or a la carte upgrades.

The Barracuda Spam Firewall is highly effective, highly customizable and is an invaluable addition to any hosting service. We at SPRHost Network use this ourselves and cannot recommend it highly enough.

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