Electronic mail is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail. Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.
Spamming is the use of messaging systems to send multiple unsolicited messages (spam) to large numbers of recipients for the purpose of commercial advertising, non-commercial proselytizing, or any prohibited purpose, or simply repeatedly sending the same message to the same user. While the most widely recognized form of spam is email spam, the term is applied to similar abuses in other media: instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, wiki spam, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social spam, spam mobile apps, television advertising and file sharing spam. It is named after Spam, a luncheon meat, by way of a Monty Python sketch about a restaurant that has Spam in almost every dish in which Vikings annoyingly sing "Spam" repeatedly.
An open mail relay is a Simple Mail Transfer Protocol (SMTP) server configured in such a way that it allows anyone on the Internet to send e-mail through it, not just mail destined to or originating from known users. This used to be the default configuration in many mail servers; indeed, it was the way the Internet was initially set up, but open mail relays have become unpopular because of their exploitation by spammers and worms. Many relays were closed, or were placed on blacklists by other servers.
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.
In computer terminology, a honeypot is a computer security mechanism set to detect, deflect, or, in some manner, counteract attempts at unauthorized use of information systems. Generally, a honeypot consists of data that appears to be a legitimate part of the site which contains information or resources of value to attackers. It is actually isolated, monitored, and capable of blocking or analyzing the attackers. This is similar to police sting operations, colloquially known as "baiting" a suspect.
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.
Hashcash is a proof-of-work system used to limit email spam and denial-of-service attacks. Hashcash was proposed in 1997 by Adam Back and described more formally in Back's 2002 paper "Hashcash - A Denial of Service Counter-Measure". In Hashcash the client has to concatenate a random number with a string several times and hash this new string. It then has to do so over and over until a hash beginning with a certain number of zeros is found.
A Joe job is a spamming technique that sends out unsolicited e-mails using spoofed sender data. Early Joe jobs aimed at tarnishing the reputation of the apparent sender or inducing the recipients to take action against them, but they are now typically used by commercial spammers to conceal the true origin of their messages and to trick recipients into opening emails apparently coming from a trusted source.
Yahoo! Mail is an email service offered by the American company Yahoo, Inc. The service is free for personal use, with an optional monthly fee for additional features. Business email was previously available with the Yahoo! Small Business brand, before it transitioned to Verizon Small Business Essentials in early 2022. Launched on October 8, 1997, as of January 2020, Yahoo! Mail has 225 million users.
Disposable email addressing, also known as DEA, dark mail or masked email, refers to an approach that involves using a unique email address for each contact or entity, or using it for a limited number of times or uses. The benefit to the owner is that if anyone compromises the address or utilizes it in connection with email abuse, the address owner can easily cancel it without affecting any of their other contacts.
Email harvesting or scraping is the process of obtaining lists of email addresses using various methods. Typically these are then used for bulk email or spam.
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.
Blue Frog was a freely-licensed anti-spam tool produced by Blue Security Inc. and operated as part of a community-based system which tried to persuade spammers to remove community members' addresses from their mailing lists by automating the complaint process for each user as spam is received. Blue Security maintained these addresses in a hashed form in a Do Not Intrude Registry, and spammers could use free tools to clean their lists. The tool was discontinued in 2006.
A feedback loop (FBL), sometimes called a complaint feedback loop, is an inter-organizational form of feedback by which a mailbox provider (MP) forwards the complaints originating from their users to the sender's organizations. MPs can receive users' complaints by placing report spam buttons on their webmail pages, or in their email client, or via help desks. The message sender's organization, often an email service provider, has to come to an agreement with each MP from which they want to collect users' complaints.
Email spammers have developed a variety of ways to deliver email spam throughout the years, such as mass-creating accounts on services such as Hotmail or using another person's network to send email spam. Many techniques to block, filter, or otherwise remove email spam from inboxes have been developed by internet users, system administrators and internet service providers. Due to this, email spammers have developed their own techniques to send email spam, which are listed below.
Spam reporting, more properly called abuse reporting, is the action of designating electronic messages as abusive for reporting to an authority so that they can be dealt with. Reported messages can be email messages, blog comments, or any kind of spam.
RESTENA is the high-speed network for the education and research community of the Grand Duchy of Luxembourg. The network has been operational since 1989 and connected to the global Internet since 1992.
