Suppression Lists
Suppression lists prevent emails from being sent to specific addresses, domains, or IP addresses. They're essential for maintaining email deliverability, respecting opt-outs, and protecting your sender reputation.
Overview
Mumara Campaigns supports three types of suppression:
| Type | Description | Use Case |
|---|---|---|
| Email Suppression | Block specific email addresses | Unsubscribes, complaints, invalid emails |
| Domain Suppression | Block entire domains | Competitors, high-complaint domains, invalid domains |
| IP Suppression | Block by IP address | Spam traps, fraudulent signups, bot protection |
Suppression Scope
Suppressions can be applied at two levels:
| Scope | Description |
|---|---|
| Global | Blocks the address/domain/IP across ALL contact lists |
| List-Specific | Blocks only within selected contact list(s) |
Use Global suppression for addresses that should never receive any emails (complaints, legal requests). Use List-Specific for context-dependent blocking.
Email Suppression
Navigate to Lists → Suppression → Email Suppression to manage suppressed email addresses.
Manage and review the list of email addresses that are blocked from receiving your communications. Suppressed emails are excluded from campaigns to comply with unsubscribe requests, manage bounces, or adhere to email deliverability rules.
Page Features
- Add New button to suppress new email addresses
- Re-Sync Suppression button to update contact statuses
- Bulk Actions dropdown for operations on selected items
- Our records / User records toggle to filter between admin and user records
- Filter by admin dropdown to filter by creator
Suppression list synchronizes every 15 minutes. Newly suppressed addresses may take a sync cycle to fully take effect.
Viewing Suppressed Emails
The table displays:
| Column | Description |
|---|---|
| ID | Unique suppression identifier |
| The suppressed email address | |
| Reference | Label explaining why it was suppressed (e.g., "Hard") |
| Associated List | Specific list or "Global" (clickable link) |
| User | Who added the suppression |
| Created On | When it was added |
| Actions | Delete (X) and export icons |
Adding Email Suppressions
Click Add New to open the "Suppress Email Addresses" modal.
Suppression Settings
| Field | Description |
|---|---|
| Select List | Choose Global or a specific contact list |
| Email Hashing | No Hashing or MD5 Hash |
| Source | How to provide email addresses |
| Select List (file) | Browse to select file (Maximum file size 250MB) |
| Reference | Tag explaining why these emails are suppressed |
| Rocket import | Toggle to enable faster import processing |
Source Options
| Method | Description |
|---|---|
| Upload a CSV file | Upload a CSV file from your computer |
| Select a file from server | Choose a file already on the server |
| Input email addresses | Enter emails manually |
Manual Entry
Enter email addresses one per line:
MD5 Hashed Emails
Mumara supports importing suppression lists with MD5-hashed email addresses:
| Option | Description |
|---|---|
| No Hashing | Plain text email addresses |
| MD5 Hash | Emails are MD5 hashed |
When using MD5 hashed suppression, Mumara hashes contact emails during sending to check for matches.
Re-sync Suppression
After removing emails from global suppression, click Re-Sync Suppression to update contact statuses across all lists.
Domain Suppression
Navigate to Lists → Suppression → Domain Suppression to manage suppressed domains.
Suppress entire domains that you no longer want to send emails to. This is useful for domains that generate high complaint rates or deliver poor ROI, ensuring your emails reach only valuable and responsive recipients.
Page Features
- Add New button to suppress new domains
- Bulk Actions dropdown for operations on selected items
- Our records / User records toggle to filter between admin and user records
- Filter by admin dropdown to filter by creator
Suppression list synchronizes every 15 minutes.
Viewing Suppressed Domains
The table displays:
| Column | Description |
|---|---|
| Domain | The suppressed domain |
| Reference | Label for the suppression (e.g., "manual ban", "bad complaint") |
| Associated List | Specific list or "Global" |
| Created On | When it was added |
| Actions | Action menu (three dots) |
Adding Domain Suppressions
Click Add New to open the "Suppress Domains" modal.
Suppression Settings
| Field | Description |
|---|---|
| Select List | Choose Global or a specific contact list |
| Source | How to provide domains |
| Select List (file) | Browse to select file (Maximum file size 250MB) |
| Reference | Tag explaining why these domains are suppressed |
| Rocket import | Toggle to enable faster import processing |
Source Options
| Method | Description |
|---|---|
| Upload a CSV file | Upload a CSV file from your computer |
| Select a file from server | Choose a file already on the server |
| Input domains | Enter domains manually |
Manual Entry
Enter domains one per line (without @):
competitor.com
disposable-email.org
spam-domain.net
How Domain Suppression Works
When a domain is suppressed:
- All email addresses at that domain are blocked
[email protected],[email protected]- all blocked- Existing contacts from that domain are marked as suppressed
- New contacts with that domain cannot receive emails
Invalid domain formats will be rejected. Ensure domains are properly formatted.
Use Cases for Domain Suppression
| Scenario | Example |
|---|---|
| Block competitors | competitor.com |
| Block disposable emails | mailinator.com, tempmail.com |
| Block role addresses | Suppress domains known for role addresses |
| Block high-complaint domains | Domains with frequent spam complaints |
IP Suppression
Navigate to Lists → Suppression → IP Suppression to manage IP-based suppressions.
Automatically suppress contacts that engage from an IP address listed in the IP suppression table. When a contact interacts with your emails, the system cross-references the IP address with the suppression list. If a match is identified, the contact is suppressed, ensuring no further emails are sent to them.
Page Features
- Add New button to suppress new IP addresses
- Bulk Actions dropdown for operations on selected items
- Our records / User records toggle to filter between admin and user records
- Filter by admin dropdown to filter by creator
Suppression list synchronizes every 15 minutes.
How IP Suppression Works
IP suppression works differently from email/domain suppression:
- When a contact engages with your email (opens, clicks)
- The system captures their IP address
- If the IP matches a suppressed IP, the contact is suppressed
- The suppressed contact won't receive future emails
IP suppression only affects contacts who have engaged with emails. Contacts who have never opened or clicked are not checked against IP suppression lists.
Viewing Suppressed IPs
The table displays:
| Column | Description |
|---|---|
| IP Address | Individual IP or range |
| Associated List | Specific list or "Global" |
| Reference | Label for the suppression (e.g., "Complaint", "bots") |
| Created On | When it was added |
| Actions | Action menu (three dots) |
Adding IP Suppressions
Click Add New to open the "IP Suppression" modal.
Suppression Settings
| Field | Description |
|---|---|
| IP Address | Enter IP addresses (one per line) |
| Contact List | Choose Global or a specific contact list |
| Reference | Tag explaining why these IPs are suppressed |
IP Address Formats
Enter IPs one per line. Supported formats:
| Format | Example | Description |
|---|---|---|
| Single IP | 192.168.1.0 | One specific IP |
| IP Range | 192.168.1.0-20 | Range of IPs (last octet range) |
| Subnet (CIDR) | 192.168.1.0/28 | CIDR notation |
Example input:
192.168.1.0
192.168.1.0-20
192.168.1.0/28
Use Cases for IP Suppression
| Scenario | Description |
|---|---|
| Known spam traps | IPs associated with spam trap networks |
| Bot networks | IPs from known bot farms |
| Fraudulent signups | IPs with suspicious signup patterns |
| Data centers | Non-human IPs (proxy services, VPNs) |
| Geographic blocking | IPs from regions you don't serve |
Import Progress
When importing suppression lists, you'll see:
| Metric | Description |
|---|---|
| Total | Records in the file |
| Imported | Successfully suppressed |
| Duplicates | Already in suppression |
| Invalid | Invalid format |
Background Processing
Large imports run in the background:
- You can leave the page
- Check back for completion status
- Download the processed file if needed
Canceling Imports
Click Cancel import to stop an in-progress import. Already processed records remain suppressed.
Suppression Sync
Suppression list synchronizes every 15 minutes. Newly suppressed addresses may take a sync cycle to fully take effect.
If suppression processing is disabled, you'll see a notice. Contact your administrator to enable it.
To manually trigger a sync for email suppressions, click Re-Sync Suppression on the Email Suppression page.
Automatic Suppression
Contacts are automatically suppressed when:
| Event | Result |
|---|---|
| Hard bounce | Email added to suppression |
| Spam complaint | Email added to suppression |
| Unsubscribe | Email marked as unsubscribed (not suppressed) |
| Manual suppression | Explicitly added by user |
| Import | Bulk imported to suppression |
Removing Suppressions
Single Removal
- Find the suppressed item in the list
- Click the Delete icon
- Confirm removal
Bulk Removal by Reference
- Find items with the reference
- Click Flush reference
- Confirm removal
All items with that reference are removed.
After Removal
After removing from global suppression:
- Click Re-sync Suppression to update contact statuses
- Contacts are no longer marked as suppressed
- They can receive emails again
Before un-suppressing contacts, ensure you have permission to email them. Re-emailing complainers or invalid addresses harms deliverability.
Viewing Suppressed Contacts
When viewing contacts in a list:
- Suppressed contacts show a "Suppressed" indicator
- The suppression type is tracked (email, domain, or IP)
In contact details, you can see:
- Whether the contact is suppressed
- The type of suppression
- The reference (if applicable)
Best Practices
Building Suppression Lists
- Import known bad addresses: Before campaigns, import addresses you know are invalid
- Add competitors: Suppress competitor domains
- Include role addresses:
admin@,info@,support@can be problematic - Honor opt-outs immediately: Suppress complaint addresses right away
Maintaining Suppression Lists
- Regular reviews: Periodically review suppression lists
- Document references: Use clear reference labels
- Export backups: Keep copies of suppression lists
- Monitor additions: Track why addresses are being suppressed
Compliance
- CAN-SPAM compliance: Suppress unsubscribe requests within 10 days
- GDPR compliance: Handle deletion requests appropriately
- Legal requests: Maintain suppression for legal opt-out requests
- Industry lists: Subscribe to industry suppression list services
Deliverability
- Remove bounces quickly: Hard bounces should be suppressed immediately
- Handle complaints seriously: One complaint can affect your reputation
- Test before sending: Verify suppression is working before large campaigns
- Monitor suppression growth: Rapid growth may indicate list quality issues
Troubleshooting
Contact Still Receiving Emails
Possible causes:
- Suppression sync hasn't run yet
- Suppressed in wrong list (not global)
- Different email variation not suppressed
Solutions:
- Wait for sync cycle or trigger manual sync
- Check suppression scope (global vs list-specific)
- Verify exact email address is suppressed
Import Showing Many Invalids
Possible causes:
- Incorrect file format
- Wrong column selected
- Invalid email/domain formats
Solutions:
- Verify CSV format and delimiters
- Check mapping during import
- Clean file before importing
IP Suppression Not Working
Possible causes:
- Contact hasn't engaged yet
- IP not in correct format
- Range syntax incorrect
Solutions:
- IP suppression only works after engagement
- Verify IP format (use proper CIDR notation)
- Test with single IPs first
Re-sync Not Updating Contacts
Possible causes:
- Sync process still running
- Large database taking time
- Process disabled by admin
Solutions:
- Wait for sync to complete
- Check suppression cron settings
- Contact administrator
Next Steps
- Contact Lists - Manage your lists
- Contacts - View and manage subscribers
- Segments - Create targeted groups