Frequently Asked Questions (FAQ)
About MailMum
Is MailMum a public blacklist?
No. Every list on MailMum is private to the account that created it. MailMum is self-hosted and privately managed — it’s the engine for running your own DNSBL, not a subscription to a shared, global reputation database like Spamhaus or SpamCop.
Does MailMum see my email content?
No. MailMum only ever sees the connection-level information a standard RBL lookup exposes: the connecting IP address and which of your mail servers it tried to reach. It never receives, stores, or scans message content, attachments, or headers — that’s a job for your MTA and content filters like SpamAssassin or Rspamd, not MailMum.
What does MailMum log, and for how long?
Every DNS query MailMum answers becomes a permanent record: the source IP, the destination server, whether it was blocked or passed, and the timestamp. This audit trail is what lets you review, later, exactly what connected to your mail servers and what MailMum did about it.
Can multiple teams or clients share one MailMum installation?
Yes. MailMum is multi-tenant by design: one installation can host many independent accounts, each with its own users, servers, lists, and role-gated admins/viewers. This is the setup ISPs, hosting providers, and MSPs use to run isolated mail security for many customers from a single deployment — see who MailMum is for for details.
Where does the network ownership information come from?
For incoming IPs, MailMum automatically fetches and caches network/ownership information — who operates the network behind an address — so you don’t have to look it up by hand while investigating a sender. This enrichment is refreshed periodically and deduplicated behind the scenes.
How do I connect my mail server to MailMum?
Add your server in MailMum to get a unique identifier, then point your mail server’s existing RBL check at MailMum, the same way you’d configure any public list. Full setup steps for Postfix, Exim, and other systems are in the MailMum documentation.
IP Blacklisting
What is IP blacklisting?
IP blacklisting is a technique used to block specific IP addresses from delivering email to a particular email system by rejecting the connection.
How is a blacklist created?
To create a blacklist, an administrator must identify IP addresses that are abusive in any way (spam, malware or any other malicious activity) and shouldn’t be allowed to send any emails to the system.
How is a blacklist implemented?
The blacklist is implemented in the email system’s configuration, and the system will reject incoming connections from the IP addresses on the blacklist.
What are the benefits of using a blacklist?
By using a blacklist, an email system can help ensure that abusive sources are unable to send messages, and can improve the security and reliability of the system.
Are there any drawbacks to using a blacklist?
One potential drawback to using a blacklist is that it can be difficult to manage and maintain. It is important to regularly review and update the blacklist to ensure that it remains accurate and effective.
IP Whitelisting
What is IP whitelisting?
IP whitelisting is a technique used to allow specific IP addresses to send email to a particular email system, bypassing IP blacklists.
How is a whitelist created?
To create a whitelist, an administrator must identify the IP addresses that are trusted and should be allowed to send email to the system. These IP addresses are then added to a local whitelist or an IP whitelist system.
How is a whitelist implemented?
The whitelist is implemented in the email system’s configuration, and the system will accept incoming messages from the IP addresses on the whitelist.
What are the benefits of using a whitelist?
By using a whitelist, an email system can help ensure that only trusted sources are able to send messages, and can improve the security and reliability of the system.
Are there any drawbacks to using a whitelist?
One potential drawback to using a whitelist is that it can be difficult to manage and maintain. It is important to regularly review and update the whitelist to ensure that it remains accurate and effective.