Set Allowed and Blocked Sender Lists

Hosted Email lets you approve or block specific addresses, domains, and IP ranges by maintaining allow and block lists at four levels: user, domain, company, and global. Use these lists to override spam scoring for trusted contacts, stop persistent spam sources, and protect against attacks on a particular tenant. This article explains how the lists interact and how to set them at each level.

How list hierarchy and precedence work

Hosted Email evaluates allow and block lists in a fixed order. Higher-priority lists win over lower-priority ones, and IP block lists override any allow entry at any level.

Precedence from highest to lowest

1. IP address block list
2. User allow list
3. User block list
4. Domain allow list
5. Domain block list
6. Company allow list
7. Company block list
8. Global allow list
9. Global block list
10. User address book (treated as implicit safe senders)

Entries in a user's personal address book are treated as safe senders for that user by default, even though those addresses do not appear in the visible allow list. If the same address is added to the user's block list, the block wins.

The global allow and block lists are maintained by OpenSRS and used for system-wide protection during incidents such as active attacks. They are normally empty.

Before you begin

• Decide which level — user, domain, or company — is the right scope for the change. Lower-scope changes affect fewer mailboxes.
• You can add up to 1,000 entries to each list and use up to five wildcard characters per entry. To block all addresses on a domain, use the format *@domain.tld.
• Sign in to the Reseller Control Panel or the Mail Administration Console (MAC), depending on which interface you prefer.

Step 1: Set user-level allow and block senders

User-level lists override every other level except IP block lists. Use them for changes that should affect only one mailbox.

Using the Reseller Control Panel

1. In the Email section of the Reseller Control Panel, navigate to the email domain for the user.
2. Select the email address to open the user's settings page.
3. In the Spam filtering section, click Edit.
4. Click the + button below Safe senders or Block senders, enter the email address or domain, then click Save.

Using the MAC

1. Sign in to the Mail Administration Console (MAC).
2. Locate the user you want to edit and select their user name.
3. In the Spam settings section, add addresses or domains to the appropriate text box. List one entry per line.
4. Click Update.

Step 2: Set domain-level allow and block senders

Domain-level lists apply to every mailbox on that domain. Use them when the same sender should be allowed or blocked for an entire customer.

Using the Reseller Control Panel

1. In the Email section of the Reseller Control Panel, open the Email domains tab.
2. Select the domain, then open the Settings tab.
3. In the Spam filtering section, click Edit.
4. Click the + button below Safe senders or Block senders, enter the email address or domain, then click Save.

Using the MAC

1. Sign in to the MAC.
2. Navigate to the domain you want to modify.
3. Add addresses or domains to the appropriate list box — Allow, Block, or IP block. List one entry per line.
4. Click Update.

Step 3: Set company-level allow and block senders

Company-level lists apply to every domain and mailbox under your reseller account. Use them when you need broad protection across all customers.

Using the Reseller Control Panel

1. In the Email section of the Reseller Control Panel, open the Settings tab.
2. In the Spam filtering section, click Edit.
3. Click the + button below Safe senders or Block senders, enter the email address or domain, then click Save.

Using the MAC

1. Sign in to the MAC.
2. In the left navigation, click your company name.
3. Add addresses or domains to the appropriate list box — Allow, Block, or IP block. List one entry per line.
4. Click Update.

Step 4: Mark an inbox message as spam

If a spam message reaches the inbox, marking it as spam trains the filter using the sender, headers, and content. Marking a message as not spam teaches the filter to treat similar messages as safe.

1. Select the message in webmail and choose Spam.
2. Press Accept to confirm the message as spam.

Next steps

• Tune the spam threshold for affected users. If a user still sees spam in the inbox, increase their spam threshold. See Managing Missed Spam Messages.
• Understand how scoring works. Learn what the X-Spam-Status and X-User headers mean and how per-user training shapes verdicts. See Hosted Email Spam-Scanning Solution.
• Diagnose delivery failures. If mail is bouncing or being refused at SMTP, work through the OpenSRS Hosted Email Spam and Rejections Guide.

Questions? Contact OpenSRS Support.