E-Mail - Junk E-Mail Filtering Overview

pair Networks Web hosting accounts include the ability to flag and filter junk e-mail. Our e-mail delivery system provides filtering features such as greylisting, the popular Open Source junk e-mail filtering tool SpamAssassin, and an Open Source virus scanner, ClamAntiVirus.

Two steps are required to use junk e-mail filtering with your account. First, filtering must be turned on for each mailbox or recipe. Second, your e-mail reader (such as Outlook, Mac Mail, etc.) must be configured to recognize junk e-mail flagged by our system.

If you have already enabled junk e-mail filtering and just need to configure your e-mail reader, please read the article Junk E-Mail Filtering and Your E-Mail Reader.

Below are the most common questions regarding our junk e-mail filtering system:

»	How do I enable filtering for a new mailbox or recipe?
»	How do I turn on junk e-mail filtering for existing recipes and mailboxes?
»	What is greylisting and how does it work?
»	How does ClamAntiVirus work?
»	How does SpamAssassin work?
»	How do I customize junk e-mail filter settings?
»	What are the settings that affect SpamAssassin junk e-mail filtering?
»	How else are e-mail messages marked?
»	Can I automatically accept e-mail from specific addresses?

How do I enable filtering for a new mailbox or recipe?

When you create an e-mail delivery recipe in the Account Control Center, you will see a check box labeled "Enable Junk E-Mail Filtering." Checking this box enables junk e-mail filtering for the recipe. Junk e-mail will be marked as Junk in the e-mail headers, but it will still be delivered as the recipe specifies.

When you create a new mailbox, you will have 3 options for junk e-mail filtering:

• Do not filter junk mail for this mailbox: no junk e-mail filtering will apply to the mailbox.
• Mark junk mail and store it in the mailbox: junk e-mail will be marked in the e-mail headers so your e-mail reader can filter it.
• Store junk in the Junk mail folder: junk e-mail will delivered to your Junk IMAP folder instead of to the mailbox's INBOX.

The junk e-mail filtering option you choose here will also automatically apply to all MAILBOX recipes that deliver mail to this mailbox.

If you store junk e-mail in the Junk mail folder, your e-mail reader will have access to view or delete junk messages as long as you use pair Networks webmail or an IMAP based mail reader. The junk e-mail folder is not accessible using POP3.

Note that if you store junk e-mail in the Junk folder, junk e-mail messages may impact your monthly disk space allotment. Be sure to empty your Junk folder frequently to prevent this, with either an IMAP e-mail client or pair Networks webmail servers. Some e-mail clients can store junk e-mail messages on your home computer instead of on the e-mail server, which can also reduce your total disk usage.

How do I turn on junk e-mail filtering for existing recipes and mailboxes?

To turn on junk e-mail filtering for an existing recipe, follow these steps:

1. Log into the Account Control Center (https://my.pair.com).
2. Click E-Mail Management (located in the middle of the page).
3. Click the Delivery Instructions link of the domain that contains the recipe you wish to modify (located under the Mail Delivery Settings by Domain heading).
4. Click on the recipe link of the recipient address that contains the recipe you wish to modify (located under the Delivery Instructions heading).
5. Click the Junk E-Mail Filtering checkbox.
6. Click Commit Changes.

If you have created multiple recipes for one recipient address, turning on junk e-mail filtering for a single recipe will turn on junk e-mail filtering for all recipes on that recipient address.

Please note that junk e-mail filtering is handled separately for each mailbox. Mailboxes will not receive junk filtered e-mail messages unless their own junk e-mail filtering setting is turned on. This is the case even if the mailbox's recipes have junk e-mail filtering turned on.

To turn on e-mail filtering for an existing mailbox, follow these steps:

1. Log into the Account Control Center (https://my.pair.com).
2. Click E-Mail Management (located in the middle of the page).
3. Click the Delivery Instructions link of the domain that contains the recipe you wish to modify (located under the Mail Delivery Settings by Domain heading).
4. Click on the mailbox link of the mailbox you wish to modify (located under the Delivery Instructions heading).
5. Select one of the junk filtering options:
   
   • Do not filter junk mail for this mailbox: no junk e-mail filtering will apply to the mailbox.
   • Mark junk mail and store it in the mailbox: junk e-mail will be marked in the e-mail headers so your e-mail reader can filter it.
   • Store junk in the Junk mail folder: junk e-mail will delivered to your Junk IMAP folder instead of to the mailbox's INBOX.
6. Click Commit Changes.

What is greylisting and how does it work?

Greylisting is a technique used to reduce the delivery of junk e-mail while allowing legitimate e-mail messages to be delivered. It takes advantage of the fact that the servers that deliver junk e-mail rarely attempt to redeliver e-mail if there is a temporary failure.

Greylisting looks at the IP address of the sender and the recipient address. If the system does not recognize this information, then it will temporarily reject the e-mail. All legitimate e-mail systems will attempt to resend the e-mail at a later time, and the e-mail will go through.

Most applications that send junk e-mail just send junk e-mail messages once and do not attempt to resend them. These junk e-mail applications use the "fire-and-forget" method, which means that if the junk e-mailer was unsuccessful at sending junk e-mail to a particular e-mail address, the application will not try to resend that e-mail message.

Greylisting does not delete legitimate e-mail messages. All legitimate e-mails will be successfully delivered using greylisting. The only potential effect greylisting may have for pair Networks customers is a slight delay in the delivery of legitimate e-mail messages.

Greylisting is turned "ON" by default for the mailboxes and recipes for which you have enabled junk e-mail filtering. You can easily disable greylisting via the Account Control Center (see the question below about customizing junk e-mail filter settings).

However, these delays can be avoided by adding e-mail addresses to your "Accepted Addresses" list. Any e-mail address in your "Accepted Addresses" list will not be subjected to greylisting.

How does ClamAntiVirus work?

pair Networks uses the open-source application ClamAntiVirus to scan e-mail for viruses. This software will reject e-mail messages that it flags as containing viruses. These infected e-mail messages will never be delivered.

We strongly recommend that you use other anti-virus software to protect you from viruses, spyware, and other potentially harmful applications. pair Networks uses the open-source software ClamAntiVirus to scan e-mails for viruses. You can obtain viruses in many different ways and need to use other anti-virus software to protect yourself from viruses.

How does SpamAssassin work?

SpamAssassin scans each e-mail message for phrases and structures that are common to Junk E-Mail and then assigns a numeric score based on what it finds. If a message's score exceeds the limit you've configured, headers are added to mark the message as junk e-mail.

How do I customize junk e-mail filter settings?

1. Log into the Account Control Center (https://my.pair.com).
2. Select E-Mail Management.
3. Click Junk E-Mail Filter Settings under the General E-Mail Settings section.
4. Modify junk e-mail settings.
5. Click Commit Changes.

To use these settings, you must first turn on junk e-mail filtering on each mailbox and recipe.

What are the settings that affect SpamAssassin junk e-mail filtering?

There are three settings which affect junk e-mail filtering: Filter Sensitivity Level and E-Mail Subject.

• Filter Sensitivity Level
  The sensitivity level controls how high of a score is required before an e-mail is considered junk. Try the different levels to find out which works best for you.

  Very Aggressive (Score required: 3.0)
  This setting should flag almost all junk e-mail messages, but it is also more likely than other settings to miscategorize legitimate e-mail messages.

  Aggressive (Score required: 3.5)
  This setting may fail to recognize a few junk e-mail messages, but it will flag fewer legitimate messages.

  Default (Score required: 4.0)
  This is our recommended level. While it may still flag some legitimate messages, it is the most balanced setting.

  Forgiving (Score required: 5.0)
  This setting is less likely to flag legitimate messages, but will recognize fewer junk e-mail messages.

  Light (Score required: 6.0)
  This setting is least likely to flag legitimate messages, but will fail to recognize many junk e-mail messages.

• E-Mail Subject
  This setting will modify flagged messages to include "**JUNK**" in the Subject line. This allows easier identification of flagged messages when reviewing Subject lines, and may also be required for your e-mail reader to recognize flagged messages.

How else are e-mail messages marked?

Several other headers are added to each message that is scanned. The two most useful headers are the following:

X-Spam-Flag: NO
X-Spam-Level: *

With most e-mail readers, the header "X-Spam-Flag" will be used to identify messages flagged as junk. This header will be set to "YES" on flagged messages, and to "NO" on unflagged messages.

To learn about configuring your e-mail client to automatically recognize messages flagged as junk, please read the article Junk E-Mail Filtering and Your E-Mail Reader.

The "X-Spam-Level" header relates to the score assigned to the message. It will contain a number of stars equal to the whole number of the score. For example, a score of 5.2 or 5.5 would result in this header reading "X-Spam-Level: *****".

Can I automatically accept e-mail from specific addresses?

You may maintain two lists of specific e-mail addresses which affect the filtering system. The first list, known as a "whitelist," contains sender addresses which prevent a message from being flagged as junk. The second list, known as a "blacklist," contains sender addresses which automatically cause a message to be flagged as junk.

In the Account Control Center (ACC), you can maintain your whitelists and blacklists from the Junk E-Mail Settings page. You may add individual e-mail addresses or entire domain names to either list. While on the Junk E-Mail Filter Settings page, click Add, Remove, or View Accepted Addresses to always accept, or "whitelist," certain e-mail addresses. Click Add, Remove, or View Addresses to Mark as 'Junk' to "blacklist" certain e-mail addresses.

In addition, e-mail from "envelope senders" on your blacklist will be rejected by the server and not sent to you. An "envelope sender" is the e-mail address that the remote server says an e-mail message is from before pair Networks' system has given them permission to send the e-mail message.

Remember that flagging a message as junk e-mail does not cause it to be deleted. Flagged messages must be handled by your e-mail reader or an additional e-mail processing recipe.

Additional Resources:

• Junk E-Mail Filtering and Your E-Mail Reader
• Junk E-Mail Filtering: Advanced Options
• SpamAssassin (external link)