MX Records
Anti-spam filtering is enabled by changing the domain's MX records to route incoming emails to the filtering servers first before passing the message off to the MX machines for delivery. Domains using non-DreamHost nameservers will need to manually update their MX records to reflect the change.
The filter records are:
- 0 mx1.mailchannels.net
- 0 mx2.mailchannels.net
Special considerations for forwarding addresses
There are certain things to remember with filtering in relation to forwarding email addresses. The details for the four combinations with this setup are outlined below:
- If the domain is being filtered, and the address is being forwarded to another DreamHost email address that is also filtered, then email gets sorted based on the filter mail settings of the original forwarding address.
- If the domain is being filtered, and the address is being forwarded to another DreamHost email address that is not filtered, then the email will be filtered.
- If the domain is being filtered, and the address is being forwarded to an outside address only (like @gmail), then the filter settings for the outside address will be used.
- If the domain is not being filtered and it forwards to a DreamHost email address that is on a filtered domain, then the email will not be filtered.
The following table shows how Anti-spam filtering works for/with forward-only addresses. A@example.com is forward-only and sends emails to B@example.net which is a fully hosted mail account:
| A@example.com uses filtering | B@example.net uses filtering | Is filtering done on incoming mail? | What filter is used? |
|---|---|---|---|
| Yes | Yes | Yes | A@example.com |
| Yes | No | Yes | A@example.com |
| No | Yes | No | N/A |
| No | No | No filtering done | N/A |
Filtering and what it does
There are three services currently set up to filter spam. Below is a description of each:
- Vade Secure (soon to be removed)
- This is the filter service that scans the incoming messages for spam and other categories such as social or promotional emails. Depending on multiple factors, the message will be tagged with a status (SPAM, SN, etc) to determine if the message should be delivered to the recipient's inbox, or filtered into the Spam folder. However, spam emails that are beyond a certain threshold will be rejected.
- Procmail
- This is the delivery agent for the mailbox which actually places the email into Spam, Social or Promotions folders when it detects the Vade Secure headers. This is also responsible for the user defined filters defined in the panel.
- Mailchannels (enabled as of Sept 2020)
- Mailchannels is a Cloud-based mail filter. It accepts and evaluates mail, adds a specific header for spam messages, then relays messages to MX servers.
