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Stopping Spam Creating a Stronger, Safer Internet
GLOSSARY
- Address harvesting
- The collection of lists of email addresses by automated means from websites or other online sources.
- Black list
- A list of IP addresses, domains or email addresses from which email is not accepted. The most
common form of black list is a Domain Name System black list (DNSBL), a list of IP addresses
distributed via the Internet's DNS. Popular DNSBLs include the Spamhaus Black List (SBL), the
Composite Black List (CBL) and the original DNSBL, called the Mail Abuse Prevention System
(MAPS) Reverse Black List (RBL). Contrast this with "white list."
- Botnet
- A collection of "zombies" used to send spam or for another purpose. A single botnet often contains
hundreds or thousands of computers.
- Bounces
- The process of rejecting the attempted delivery of an email message. Sometimes a stylized "bounce
report" email message reports that a previous message couldn't be delivered.
A bounce may be a "soft bounce," in which case the sending computer can retry the delivery later,
or a "hard bounce," in which case the delivery is a failure.
A soft bounce may occur because the recipient's mailbox is full, the server is overloaded or there
are other temporary problems. A hard bounce most often occurs because the recipient address is
invalid or the recipient host, by policy, rejects mail from that sender.
- Clickstream
- The series of mouse clicks and related actions that a user makes while visiting a website. For an
e-commerce website, a clickstream might include browsing the catalog, putting items into a virtual
shopping cart, providing payment and shipping information, and then entering the order.
- Cookie
- A small data file created by a web server and stored on a user's computer. Cookies are a way for
websites to identify users, keep track of users' preferences and recognize users who are revisiting
the website. By keeping user histories, cookies let websites tailor pages and create custom experiences
for individuals. Depending on how the web server is programmed, cookies may also contain
personal information, such as site passwords and account numbers.
First-party cookies are ones created by the website you are visiting. Third-party cookies are created
by a website other than the one you are currently visiting, most often a third-party advertiser on
that site. Third-party cookies let advertisers determine whether an individual user is visiting multiple
websites that display the advertiser's ads, and are often considered a privacy risk.
Modern web browsers offer options to refuse all cookies, to refuse third-party cookies and/or to
accept or refuse cookies from specified websites.
- Cross-sell
- To encourage a customer to buy a product or service related to one already purchased. Contrast
this with "up-sell."
- Denial of service attack
- Often abbreviated as DoS or DOS. An attempt to keep a server or network from performing its
intended function, by flooding it with unwanted traffic. For example, an attacker could send tens
of thousands of email messages to a mail server to overload it and keep it from processing desired
mail. Many different DOS attacks and targets are possible, including attacks on mail servers, web
servers, DNS servers and network routers. Spam sent in large volume can act as a DOS attack on
mail servers.
- Dictionary attack
- An email-address guessing technique. The attacker tries to deliver email to a large number of
made-up addresses, using either words out of a dictionary or letter combinations such as
aaaa@example.ca, aaab@example.ca or zzzz@example.ca.
- DNS
- Domain Name System, the system that lets users locate computers on the Internet by domain
name. DNS servers maintain a database of domain names (i.e. host names) and their corresponding
IP addresses. For example, if the name www.mycompany.ca were presented to a DNS server, the
IP address 204.0.8.51 might be returned. The DNS includes several different kinds of data, such as
A records for IP addresses and mail exchanges (MXs) for mail servers.
The DNS is distributed among many different servers, with most servers delegating responsibility
for names to other servers. In the example above, the Internet Assigned Numbers Authority (IANA),
which is responsible for the entire DNS, would delegate all of .ca to the Canadian Internet
Registration Authority (CIRA), which, in turn, would delegate all of .mycompany.ca to the
registrant for that name, which, in turn, would operate the DNS servers that have information
for www.mycompany.ca.
- Domain
- A name used on the Internet. Domains consist of multiple sections separated by dots, such as
ic.gc.ca or www.mycompany.com.
- Domain keys
- A technology proposal by Yahoo!® that puts a cryptographic signature on messages, which
recipients can verify. This provides a way to verify both that the message was sent from the domain
of its email sender and that the message was not altered during transit.
- EHLO/HELO identity
- The name by which a sending computer identifies itself to a receiving computer at the beginning
of each SMTP transaction. The command the sending computer uses to identify itself by this name
to the receiving computer is called the "EHLO" or "HELO" command.
- Email address
- The name by which the sender or recipient of an email is identified. Each address is of the
mailbox@dom.ain form, where dom.ain is a domain name that can be looked up in the DNS,
and mailbox is an arbitrary identifier used by the domain's management to identify a mail user.
- ESP or email service provider
- A company that provides email services to other businesses. ESP services include collecting and
maintaining lists of email addresses, sending bulk email to the addresses on the lists, removing
addresses that bounce, and dealing with complaints and abuse reports related to the mailings.
- Existing business relationship
- An existing business relationship exists where:
- the recipient has purchased a product or service from an organization within the past
18 months; and
- the recipient has not unsubscribed or opted out from commercial or promotional email
messages, or otherwise terminated the relationship.
An affiliate or third party may not rely on another organization's prior business relationship in order
to send commercial or promotional email messages.
- Filters
- Software used to separate wanted from unwanted email, based on the mail's characteristics.
Filters might check for specific text strings, approximate text patterns, similarity to other messages
or other criteria.
- Harvesting
- Shorthand for "address harvesting."
- Header
- In Internet email, the initial part of a message, consisting of a series of lines that describe the
message. Each header-line starts with a label such as From: or Subject: to identify its meaning.
The header is followed by a blank line, and then the body of the message.
- HTML
- Hypertext markup language, the coding scheme used to format web pages and formatted email
messages. HTML uses textual tags, such as <h2>A Topic</h2> to indicate a second-level header,
or <b>important text</b> to indicate bold-faced text.
- Identity theft
- The use of stolen personal information to impersonate someone, generally for financial fraud
purposes. An identity theft may involve impersonating a victim to gain access to existing bank
accounts or take out bank loans, or for other fraudulent purposes.
- IM or instant messaging
- Text messages delivered immediately from the sender's computer to recipients. Popular IM systems
include AOL® Instant MessengerTM, Yahoo!® Messenger and MSN® Messenger.
- Implied consent
- The Canadian Standards Association Model Code says that "Implied consent arises where consent
may reasonably be inferred from the action or inaction of the individual." This covers situations
where intended use or disclosure is obvious from the context, and the organization can assume,
with little or no risk, that the individual, by providing personal information, is aware of and
consents to its intended use or disclosure. (Source: Office of the Privacy Commissioner of Canada
fact sheet.)
- IP address
- Internet protocol address, the number that identifies a computer or other device attached to the
Internet. An IP address is usually written as four decimal numbers separated by dots, as in
168.0.1.10.
- Malware
- A general term for hostile software such as viruses, worms and Trojan Horses.
- Marketing email
- Email primarily advertising the availability of goods or services. Contrast this with "transactional email."
- Opt-in
- Also called "express" or "positive consent." Under this form of consent, commonly referred to as
"express consent," the organization presents an opportunity for the individual to express positive
agreement to a stated purpose. Unless the individual takes action to "opt in" to the purpose — in
other words, says "yes" to it — the organization does not assume consent. (Source: Office of the
Privacy Commissioner of Canada fact sheet.)
- Opt-out
- Also called "negative consent." The organization presents the individual with an opportunity to
express non-agreement to an identified purpose. Unless the individual takes action to "opt out" of
the purpose — that is, say "no" to it — the organization assumes consent and proceeds with the
purpose. The individual should be clearly informed that the failure to "opt out" means that the
individual is consenting to the proposed use or disclosure of information. (Source: Office of the
Privacy Commissioner of Canada fact sheet.)
- Phishing
- Impersonation of a trusted person or organization in order to steal a person's personal information,
generally for the purpose of "identity theft." For example, an email message may appear to be
from a well-known bank asking recipients to visit a website to confirm their account details, but
the website is actually controlled by a hostile party.
- Port 25 blocking
- Traditionally, every computer on the Internet has had the technical ability to send mail to any other
computer. In practice, most ISP customers send their outgoing mail to their ISP's mail server to be
forwarded along to its ultimate recipient. In recent years, the large majority of mail sent directly,
rather than via the ISP, has become spam and viruses. Many ISPs now block their customers from
sending mail directly, and require it be sent via ISP mail servers, where the ISP can do virus filtering
and take other anti-abuse measures. Since transmission control protocol (TCP) assigns each type of
service a port number, and email is sent via port 25, this is called "port 25 blocking."
Blocking port 25 for consumer dial-up and broadband customers is widely considered a best practice.
- Port 587 or SUBMIT
- An alternative facility many mail systems provide for users to send outgoing mail to the ISP's mail
server. It requires its sending users to authenticate themselves before sending, making SUBMIT
much more auditable than port 25 mail. SUBMIT is also sometimes called port 587, after the TCP
port number it uses.
- rDNS or reverse DNS
- Reverse Domain Name System, a service that looks up IP addresses to find domain names. It performs
the opposite function of the usual DNS lookup. Reverse DNS is often used to log incoming
traffic by domain name for statistical and auditing purposes. It is widely considered a best practice
for all mail client and server computers to have accurate rDNS.
- Role account
- Email accounts that must be in place and maintained by all domains with Internet connectivity, as
specified in the Internet Engineering Task Force's Request for Comments (RFCs) document series.
Such accounts include postmaster@sampledomain.ca, abuse@sampledomain.ca and
hostmaster@sampledomain.ca.
- Sender ID
- An authentication scheme, similar to SPF, sponsored by Microsoft. See "SPF."
- Server
- A computer that provides one or more services to other computers, such as email, DNS
or World Wide Web pages.
- SMTP
- Simple Mail Transfer Protocol, the scheme used to send mail from one computer to another over
the Internet. SMTP is defined in the Internet Engineering Task Force's Request for Comments series
(RFC 2821).
- Spam
- Although there is no internationally agreed-upon definition of "spam," many countries consider it
to be any bulk commercial email sent without the express consent of recipients.
- SPF
- Sender Policy Framework, an extension to the SMTP mail protocol on the Internet. It tries to
determine the legitimacy of an email message by comparing the domain in the sender's email
address to a list of computers allowed to send mail from that domain. See http://spf.pobox.com
for more information.
- Spoofing
- Impersonating another person or organization to make it appear that an email message originated
from somewhere other than its actual source.
- Spyware
- Software that collects information about a user without the user's knowledge or consent. Also, software
that modifies the operation of a user's computer without the user's knowledge or consent.
Typical kinds of spyware include keyloggers, which send a list to a third party of the keys that a
user pressed, and adware, which displays to the user advertisements selected by the adware's
owner.
- Subject line
- A line that is part of the headers at the beginning of each email message. Mail programs invariably
display the subject lines when showing a list of messages. It is widely considered a best practice for
the subject line to accurately describe the contents of the message.
- Text messaging
- Short messages consisting of text rather than images. Text messages can be either "instant
messages" or short mobile-phone messages.
- Transactional email
- Email primarily containing information about current or prior business dealings, such as
confirmation of a sale, a registration number, an invoice, or an opt-in or opt-out confirmation.
Contrast this with "marketing email."
- Transient failure
- A brief malfunction that often occurs at irregular and unpredictable times.
- Trojan Horse
- Software that, in addition to its nominal function, secretly performs a second function.
- Up-sell
- To try to sell a customer a more expensive item or a more expensive version of a product
or service. Contrast this with "cross-sell."
- URL
- Uniform resource locator, a name used to identify a web page or other online resource, typically
of the form http://www.mydomain.ca/somepage.
- Virus
- "Malware" that spreads by attaching itself to another resource on a computer. Early viruses spread
by attaching themselves to application programs, but current viruses spread by email. Contrast this
with "worm."
- Web bug
- Also called a web beacon, pixel tag, clear GIF (graphics interchange format) or invisible GIF. A way
for an HTML email message's sender to determine if and when the message was opened and read.
- West African, 419 or Nigerian scam
- An advance-fee fraud in which the perpetrator claims to be an official, typically in West Africa, who
wants the victim's help to steal large amounts of money from a government account. Also known
as 419 fraud, after the section number of Nigerian law that forbids it.
Before this scam moved to Africa, it was best known as the Spanish Prisoner, in which form it dates
from the 1600s.
- White list
- A list of email addresses or IP addresses from which a mail server is configured to accept incoming
mail. White lists can be useful as one part of an email filtering system. Compare this with
"black list."
- WHOIS
- An Internet service used to ask registrars for a domain or network's registration information.
It has not been universally implemented.
- Worm
- "Malware" that spreads directly by copying itself onto other computers through security holes in
the other computers' software. The earliest worm used a security flaw in Sun Microsystems' Solaris
systems and in VAX systems, but current worms all use flaws in Microsoft Windows. Contrast this
with "virus."
- Zombie
- A computer infected by "malware" so that the computer can be remotely controlled by the
creator, distributor or controller of the malware. The majority of spam is currently sent
through zombies.
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