As with most mail hosts, nearly 90% of all mail traffic moving through Birdhouse is spam.

Spam control on Birdhouse is handled by the excellent SpamAssassin toolkit. In addition, we use Vipul’s Razor to build a database of what other hosting services are ranking as spam.

By setting up your SpamAssassin configuration appropriately, you can reduce your spam load by more than 90% at the server level, so it never reaches your inbox.

By default, new accounts have spam controls enabled, and are configured to delete spam with a ranking of 5 or higher. You have complete, per-domain control over spam settings, and can also create mail filters tailored to specific mailboxes on your domain.

To configure SpamAssassin, find its icon in the Mail section of your cPanel interface:

The controls are pretty straightforward. By default you’ll find that spam ranked 5 or higher is auto-deleted. You can change this threshold, or disable auto-deletion altogether (not recommended).

Blacklist / Whitelist

You can use SpamAssassin to whitelist or blacklist addresses or entire domains, so that messages from those addresses will always/never be considered spam. Click the “Configure SpamAssassin” button to enter addresses or entire domains that you always/never want delivered. Domains should be entered like this:

*@domain.com

User-level filters

You can also create custom server-side filters that apply either to your entire domain or to specific mailboxes. These can be used to do things like copying mail from certain senders to a separate mailbox, auto-discarding mail from certain senders, or even piping certain messages to a perl script or program.

Look for the User-Level Filtering or Account-Level Filtering icons in the Mail section of cPanel. Account filters operate on every address under your domain, while User filters operate only on a single mailbox.

Creating filters is fairly straightforward and should be familiar to anyone who has created client-side mail filters before. An example filter is shown below.

Storing vs. Deleting Spam

If you’re not comfortable having spam automatically deleted by the server, you can elect to have suspected spam forwarded to another address on your domain — e.g. spam@yourdomain.com — so you can scan for any false positives. If you choose to do this, remember to also set up a corresponding mailbox with the same name, and configure your email application to check and/or empty it regularly. Here’s how:

1. Disable spam auto-delete
2. Click “Configure SpamAssassin” and enter a threshold number into the required_score field.
3. In cPanel, go either to User-Level Filtering or Account Level-Filtering (depending on whether you want to make this change for the whole domain or just one address).
4. Create a filter similar to the one pictured below and click Activate.

You can get as fancy as like. For example, the following filter will put all “possible spam” - ranked between 20 and 40 to a separate mailbox. Everything lower gets delivered normally, and everything higher will get caught by the auto-delete feature configured elsewhere (as above):

However, you will probably find that SpamAssassin doesn’t generate false positives very often, the and convenience of having spam deleted at the server level is well worth it.

Client-Side Spam Management

If you don’t want the server to auto-delete your spam, you can disable the option on the server and then handle spam in your mail client by using “Rules” or “Filters.” Suspected spam that is still set for delivery to your inbox will have a “***SPAM*** ” string pre-pended to the subject line. Configure your email application to look for this string in subject lines and move suspected messages to a separate mailbox.

We do NOT recommend relying exclusively on client-side filtering - the spam volume is just too great. Most users get best results with a combination of server-side and client-side spam filtering.

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