# MailMum > MailMum is a self-hosted, privately managed DNS blacklist (DNSBL) and mail-traffic audit log for organizations running their own mail infrastructure. You create, maintain and control the lists yourself — they are not a shared global reputation database. Your mail server (Postfix, Exim, rspamd, SpamAssassin, ...) performs a standard RBL-style DNS lookup against MailMum for every connecting client IP, exactly as it would query a public list such as Spamhaus. MailMum answers from your own blacklist and whitelist rules, and independently logs every query as an auditable event with network-ownership context. There is no new infrastructure to run — the RBL check is already built into your mail server. The system has been run since 2012 by freelance admins and is now offered as a product. - Setup and configuration documentation lives on a separate site: https://docs.mailmum.io/ - This site is the product site plus a technical library on IP blacklisting, IP reputation, and mail server operations. ## Product - [IP blacklisting admins can trust](https://mailmum.io/): MailMum is a self-hosted, privately-managed DNS blacklist (DNSBL) and mail-traffic audit log for organizations running their own mail infrastructure. It is all in your hands. - [Pricing](https://mailmum.io/pricing/): MailMum pricing scales with your mail servers, accounts, and DNS query volume — not a flat per-seat fee. Start free with a single server. - [MailMum Whitepaper](https://mailmum.io/whitepaper/): Whitepaper describing MailMum Services and why it provides so much value to email ecosystem. - [Frequently Asked Questions (FAQ)](https://mailmum.io/faq/): Frequently asked questions (FAQ) regarding MailMum Intelligence System ## Who MailMum is for - [MailMum for Compliance & Risk Teams](https://mailmum.io/for-compliance-teams/): Every blocked and passed connection is retained with a timestamp, matched-rule history, and network-ownership context, serving as evidence of active, enforced controls at the mail boundary. - [MailMum for CTOs & Heads of Infrastructure](https://mailmum.io/for-ctos/): A private DNSBL means no dependency on external reputation vendors for a core piece of mail security, plus a durable audit log for every inbound connection attempt. - [MailMum for Mail Server Admins](https://mailmum.io/for-mail-admins/): Run your own blacklist/whitelist without depending on a third-party RBL's listing/delisting process, with full visibility into every decision MailMum made and why. - [MailMum for MSPs Running Mail for Clients](https://mailmum.io/for-msps/): The account/server hierarchy maps directly onto client and their mail servers, so an MSP can apply a baseline blacklist per client and hand over a clean report of what was blocked and why. - [MailMum for Security / Abuse / SOC Teams](https://mailmum.io/for-soc-teams/): Connection-level logging plus automatic network-ownership enrichment gives investigators a ready-made timeline and ownership context for suspicious senders. - [MailMum for Telecom & Hosting Providers / ISPs](https://mailmum.io/for-isps/): Native multi-tenancy for providers running mail infrastructure at scale, or on behalf of many downstream customers: one MailMum deployment, many isolated accounts and servers. ## Concepts and background - [E-Mail IP Blacklisting](https://mailmum.io/email-ip-blacklisting/): IP Blacklisting in an E-Mail system is an essential security and spam control technology. - [E-Mail IP Whitelisting](https://mailmum.io/email-ip-whitelisting/): IP Whitelisting in an E-Mail system is an essential to allow trusted or important senders to pass blacklists and maybe other security measures. - [IP Address Reputation in E-Mail Systems](https://mailmum.io/ip-reputation-in-email-systems/): Frequently asked questions (FAQ) regarding MailMum Intelligence System ## Blog posts - [Howto Block Google Groups Spam in Rspamd](https://mailmum.io/posts/howto-block-google-groups-spam-in-rspamd/): Stop spammers abusing Google Groups as a delivery vehicle by adding a small Rspamd Lua rule that reliably detects the X-Google-Group-Id header. - [Howto block mailservers using uncommon TLDs in hostname through Postfix](https://mailmum.io/posts/howto-block-mailservers-using-uncommon-tlds-in-hostname-through-postfix/): Block mail servers using uncommon TLDs in their hostname to stop spam/junk, phishing and other unwanted emails. - [Howto Block Entire TLDs in Postfix](https://mailmum.io/posts/howto-block-entire-tlds-in-postfix/): Block entire TLDs in Postfix mail server to reduce spam, phishing and, other unwanted emails. - [Sending Test Emails from Shell](https://mailmum.io/posts/sending-test-emails-from-shell/): Sending test emails from shell using command mail and mutt, adding content and even attachments. - [Monitoring your Local Postfix Blacklist with Munin](https://mailmum.io/posts/monitoring-your-local-postfix-blacklist-with-munin/): Install, setup, and customize the Postfix RBL Munin plugin to monitor public blacklists and your self-built local blacklist. Compare the results visually. - [Manage Postfix Mail Server Queues like a Pro](https://mailmum.io/posts/manage-postfix-mail-server-queues/): Understand and manage Postfix email queues like a pro, with examples to fill up queues for better understanding and practice. - [Blacklisting Single Hosts, IP Addresses, and even Networks in Postfix](https://mailmum.io/posts/blacklisting-single-hosts-ip-addresses-and-even-networks-in-postfix/): Setup blacklisting single hosts, IP addresses or even whole networks for Postfix. Includes a whitelisting solution. - [Whitelisting single Hosts, IP Addresses, and even Networks in Postfix](https://mailmum.io/posts/whitelisting-hosts-ip-addresses-and-even-networks-in-postfix/): Whitelist single Hosts, IP addresses, and even networks in Postfix to stop them hitting a blacklist. - [Monitoring Postfix Email Queue and add Push Notifications](https://mailmum.io/posts/monitoring-postfix-email-queue-with-push-notifications/): Understand and monitor Postfix email queue through simple shell scripts. Customize it and add push notifications to your favorite smartphone. - [DNS flag day 2020](https://mailmum.io/posts/dns-flag-day-2020/): Be prepared for DNS flag day 2020. Check your DNS systems! - [Howto customize Roundcube webmail for your service](https://mailmum.io/posts/howto-customize-roundcube-webmail-for-your-service/): Customize your Roundcube webmail installation with logo, support URL and other details to make your service more professional. - [Certbot: renewing all Let's Encrypt certificates](https://mailmum.io/posts/certbot-renewing-all-lets-encrypt-certificates/): Force renew certbot managed Let's Encrypt certificates - especially all certificates at once. - [MailMum Project Started](https://mailmum.io/posts/project-page-started/): MailMum project officially started on 2020-01-03. It was born out of an internal project. ## Glossary - [Glossary](https://mailmum.io/glossary/): Glossary regarding email systems and related topics. - [Abuse](https://mailmum.io/glossary/abuse/): Abuse in email systems is the use of email for malicious or unlawful purposes such as spamming, phishing, or distributing malware. - [Abuse Desk](https://mailmum.io/glossary/abuse-desk/): An abuse desk is the team behind a provider's abuse@ address. It receives reports about spam, phishing and malware coming from the provider's own network and acts on them. - [Abuse Reporting Format (ARF)](https://mailmum.io/glossary/abuse-reporting-format-arf/): ARF is a standardized, MIME-based format for reporting email abuse incidents like phishing or spam between providers and abuse teams. - [Acceptable Use Policy (AUP)](https://mailmum.io/glossary/acceptable-use-policy-aup/): An acceptable use policy (AUP) defines what is and isn't allowed when using a computer system, network, or email service. - [Access Control List (ACL)](https://mailmum.io/glossary/access-control-list-acl/): An access control list (ACL) defines which users or systems are allowed to access specific resources on a network or email system. - [Access Management in E-Mail Systems](https://mailmum.io/glossary/access-management-in-email-systems/): Access management controls which users and systems are permitted to access email resources like mailboxes and servers, often via ACLs and authentication. - [Anycast Routing](https://mailmum.io/glossary/anycast-routing/): Anycast routing sends a request to the nearest of several servers sharing the same IP address, commonly used to improve DNS performance and reliability. - [Application Programming Interface (API)](https://mailmum.io/glossary/application-programming-interface-api/): An API is a set of protocols and tools that let software applications and services communicate and share functionality with each other. - [Artificial Intelligence (AI)](https://mailmum.io/glossary/artificial-intelligence-ai/): General background on AI techniques like spam classification and reputation scoring in email systems. MailMum itself uses rule-based blacklist/whitelist matching, not AI/ML scoring. - [Attack Vector](https://mailmum.io/glossary/attack-vector/): An attack vector is a method attackers use to compromise a system, such as phishing, malware, or network scanning aimed at email systems. - [Autonomous System Number (ASN)](https://mailmum.io/glossary/autonomous-system-number-asn/): An ASN is a unique number assigned to a network operator, used by routing protocols like BGP to identify a network and its routing policies. - [Backscatter](https://mailmum.io/glossary/backscatter/): Backscatter is spam-like bounce traffic generated when forged sender addresses cause other mail servers to send bounce messages to a spoofed victim. - [Bounce Message or Report](https://mailmum.io/glossary/bounce-message/): A bounce message is an automated email sent to the sender when an email is not delivered to the recipient's inbox. It contains information about why the email failed to be delivered. - [Email Service Provider (ESP)](https://mailmum.io/glossary/email-service-provider-esp/): An Email Service Provider (ESP) is an organisation that offers email hosting and management services, allowing users to send, receive, and manage emails. - [Geofeed](https://mailmum.io/glossary/geofeed/): Format for Self-Published IP Geolocation information - [Hostname](https://mailmum.io/glossary/hostname/): A hostname is the human-readable name assigned to a device or server on a network, used together with DNS to locate mail servers and other services. - [Internet Service Provider (ISP)](https://mailmum.io/glossary/internet-service-provider-isp/): An Internet Service Provider (ISP) is a company that provides internet access to customers. It does this by providing a connection to the internet via a network of servers, which allows users to access the web, send emails, and use other internet services. - [IP Block Listing or Blacklisting](https://mailmum.io/glossary/ip-blacklisting/): IP blacklisting is a way for ISPs and email providers to block incoming messages from known spammer IPs. This helps protect users from spam and other unwanted email. - [Mail Transfer Agent (MTA)](https://mailmum.io/glossary/mail-transfer-agent-mta/): A Mail Transfer Agent (MTA) is a software application responsible for the transfer of email messages between computer systems. - [Pointer Record (PTR)](https://mailmum.io/glossary/pointer-record-ptr/): A PTR record (Pointer record) is a type of DNS record that maps an IP address to a domain name, used for reverse DNS lookup. - [Reverse DNS (rDNS)](https://mailmum.io/glossary/reverse-dns-rdns/): Reverse DNS (rDNS) is a technique that resolves an IP address to a domain name, providing identification and verification of the server associated with the IP address. - [Top Level Domain (TLD)](https://mailmum.io/glossary/top-level-domain-tld/): Top Level Domain (TLD) is the last part of a DNS address (.com, .net, .org, etc.) indicating purpose or location of a domain. ## Optional - [Subscribe to our Newsletter](https://mailmum.io/newsletter-subscribe/): Join us by subscribing to our newsletter and get tutorials, news and product updates from MailMum - [Imprint](https://mailmum.io/imprint/): Imprint of MailMum Website - [Legal](https://mailmum.io/legal/): Legal hub for MailMum: imprint, data protection policy, cookies, licensing and how to reach us with legal questions. - [Data Protection Policy](https://mailmum.io/data-protection-policy/): Data Protection Policy for Mailmum website