Related Research Articles
A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query whether a sending host's IP address is blacklisted for email spam. Most mail server software can be configured to check such lists, typically rejecting or flagging messages from such sites.
Apache SpamAssassin is a computer program used for e-mail spam filtering. It uses a variety of spam-detection techniques, including DNS and fuzzy checksum techniques, Bayesian filtering, external programs, blacklists and online databases. It is released under the Apache License 2.0 and is a part of the Apache Foundation since 2004.
Various anti-spam techniques are used to prevent email spam.
Email spam, also referred to as junk email, spam mail, or simply spam, is unsolicited messages sent in bulk by email (spamming). The name comes from a Monty Python sketch in which the name of the canned pork product Spam is ubiquitous, unavoidable, and repetitive. Email spam has steadily grown since the early 1990s, and by 2014 was estimated to account for around 90% of total email traffic.
The Distributed Sender Blackhole List was a Domain Name System-based Blackhole List that listed IP addresses of insecure e-mail hosts. DSBL could be used by server administrators to tag or block e-mail messages that came from insecure servers, which is often spam.
Sender Policy Framework (SPF) is an email authentication method which ensures the sending mail server is authorized to originate mail from the email sender's domain. This authentication only applies to the email sender listed in the "envelope from" field during the initial SMTP connection. If the email is bounced, a message is sent to this address, and for downstream transmission it typically appears in the "Return-Path" header. To authenticate the email address which is actually visible to recipients on the "From:" line, other technologies such as DMARC must be used. Forgery of this address is known as email spoofing, and is often used in phishing and email spam.
The Spamhaus Project is an international organisation based in the Principality of Andorra, founded in 1998 by Steve Linford to track email spammers and spam-related activity. The name spamhaus, a pseudo-German expression, was coined by Linford to refer to an internet service provider, or other firm, which spams or knowingly provides service to spammers.
In computer networks, a reverse DNS lookup or reverse DNS resolution (rDNS) is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual "forward" DNS lookup of an IP address from a domain name. The process of reverse resolving of an IP address uses PTR records. rDNS involves searching domain name registry and registrar tables. The reverse DNS database of the Internet is rooted in the .arpa top-level domain.
SpamCop is an email spam reporting service, allowing recipients of unsolicited bulk or commercial email to report IP addresses found by SpamCop's analysis to be senders of the spam to the abuse reporting addresses of those IP addresses. SpamCop uses these reports to compile a list of computers sending spam called the "SpamCop Blocking List" or "SpamCop Blacklist" (SCBL).
SORBS was a list of e-mail servers suspected of sending or relaying spam. It had been augmented with complementary lists that include various other classes of hosts, allowing for customized email rejection by its users.
Bulletproof hosting (BPH) is technical infrastructure service provided by an Internet hosting service that is resilient to complaints of illicit activities, which serves criminal actors as a basic building block for streamlining various cyberattacks. BPH providers allow online gambling, illegal pornography, botnet command and control servers, spam, copyrighted materials, hate speech and misinformation, despite takedown court orders and law enforcement subpoenas, allowing such material in their acceptable use policies.
The Abusive Hosts Blocking List (AHBL) was an internet abuse tracking and filtering system developed by The Summit Open Source Development Group, and based on the original Summit Blocking List (2000–2002). Its DNSBLs were shut down on Jan 1, 2015 and now appear to be blacklisting the entire Internet.
Context filtering is an anti-spam / mail policy method that does not deal with the contents of the mail but rather uses the context of the SMTP connection to decide whether a mail will be accepted or not.
In networking, a black hole refers to a place in the network where incoming or outgoing traffic is silently discarded, without informing the source that the data did not reach its intended recipient.
Open Relay Behavior-modification System (ORBS), created and run by Alan Brown in New Zealand, was one of the first DNS-based Blackhole Lists (DNSBL), a means by which an internet domain may publish a list of IP addresses, in a database which can be easily queried automatically by other computer programs on the Internet. The ORBS list was used to blacklist IP addresses that were open mail relays, third-party mail servers through which spammers can relay their messages and thus attempt to obfuscate the source of the spam.
Not Just Another Bogus List (NJABL) was a DNS blacklist.
The Mail Abuse Prevention System (MAPS) is an organization that provides anti-spam support by maintaining a DNSBL. They provide five black lists, categorising why an address or an IP block is listed:
hMailServer was a free email server for Windows created by Martin Knafve. It ran as a Windows service and includes administration tools for management and backup. It had support for IMAP, POP3, and SMTP email protocols. It could use external database engines such as MySQL, MS SQL or PostgreSQL, or an internal MS SQL Compact Edition engine to store configuration and index data. The actual email messages were stored on disk in a raw MIME format. As of January 15th, 2022, active support and development were officially halted, although version 5.6 will continue to receive updates for critical bugs.
In computing, a blacklist, disallowlist, blocklist, or denylist is a basic access control mechanism that allows through all elements, except those explicitly mentioned. Those items on the list are denied access. The opposite is a whitelist, allowlist, or passlist, in which only items on the list are let through whatever gate is being used. A greylist contains items that are temporarily blocked until an additional step is performed.
Forum spam consists of posts on Internet forums that contains related or unrelated advertisements, links to malicious websites, trolling and abusive or otherwise unwanted information. Forum spam is usually posted onto message boards by automated spambots or manually with unscrupulous intentions with intent to get the spam in front of readers who would not otherwise have anything to do with it intentionally.
References
- ↑ "Lists". surbl.org.
- ↑ "Gmane -- Announcing SURBL support in SA 2.63 and 3.0 plugins". gmane.org.
- ↑ "URIBL.COM - Realtime URI Blacklist". uribl.com.
- ↑ "invaluement". invaluement.com. Archived from the original on 2012-05-05.
- ↑ "DBL - The Spamhaus Project". spamhaus.org.