Bogon filtering is the practice of blocking packets known as bogons, which are ones sent to a

computer network A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

claiming to originate from invalid or bogus

IP address An Internet Protocol address (IP address) is a numerical label such as that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface i ...

es, known as bogon addresses.

Etymology

The term ''bogon'' stems from

hacker A hacker is a person skilled in information technology who achieves goals and solves problems by non-standard means. The term has become associated in popular culture with a security hackersomeone with knowledge of bug (computing), bugs or exp ...

jargon Jargon, or technical language, is the specialized terminology associated with a particular field or area of activity. Jargon is normally employed in a particular Context (language use), communicative context and may not be well understood outside ...

, with the earliest appearance in the

Jargon File The Jargon File is a glossary and usage dictionary of slang used by computer programmers. The original Jargon File was a collection of terms from technical cultures such as the MIT Computer Science and Artificial Intelligence Laboratory, MIT AI Lab ...

in version 1.5.0 (dated 1983). It is defined as the

quantum In physics, a quantum (: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization". This me ...

of ''bogosity'', or the property of being bogus. A bogon packet is frequently bogus both in the conventional sense of being forged for illegitimate purposes, and in the hackish sense of being incorrect, absurd, and useless. An alternative etymology suggests that 'bogon' derives from a portmanteau of "bogus logon", or a logon from a place you know no one can actually logon.

Types of bogon addresses

Areas of unallocated address space are called the bogon space. These are that are not in any range allocated the

Internet Assigned Numbers Authority The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, Autonomous system (Internet), autonomous system number allocation, DNS root zone, root zone management in the Domain Name Syste ...

(IANA) or a

regional Internet registry A regional Internet registry (RIR) is an organization that manages the allocation and registration of Internet number resources within a region of the world. Internet number resources include IP addresses and autonomous system (AS) numbers. ...

(RIR) for public internet use. Bogon IPs also include some address ranges from allocated space. For example, addresses reserved for private networks, such as those in , , and , loopback interfaces like and , and link-local addresses like and can be bogon addresses. Addresses for

Carrier-grade NAT Carrier-grade NAT (CGN or CGNAT), also known as large-scale NAT (LSN), is a type of network address translation (NAT) used by ISPs in IPv4 network design. With CGNAT, end sites, in particular residential networks, are configured with private netwo ...

, Teredo, and

6to4 6to4 is an Internet transition mechanism for migrating from Internet Protocol version 4 (IPv4) to version 6 (IPv6) and a system that allows IPv6 packets to be transmitted over an IPv4 network (generally the IPv4 Internet) without the need to co ...

and documentation prefixes also fall into this category. IP packets using these as source addresses are sometimes known as

Martian packet A Martian packet is an IP packet seen on the public Internet that contains a source or destination address that is reserved for special use by the Internet Assigned Numbers Authority (IANA) as defined in , Appendix B Glossary (Martian Address F ...

Blocking and filtering

Many

ISP An Internet service provider (ISP) is an organization that provides a myriad of services related to accessing, using, managing, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non ...

s and end-user

firewall Firewall may refer to: * Firewall (computing), a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts * Firewall (construction), a barrier inside a building, designed to limit the spre ...

s filter and block bogons, because they have no legitimate use, and usually are the result of accidental misconfiguration or malicious intent. Bogons can be filtered by using router

access-control list In computer security, an access-control list (ACL) is a list of permissions associated with a system resource (object or facility). An ACL specifies which users or system processes are granted access to resources, as well as what operations are al ...

s (ACLs), or by

BGP Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous system (Internet), autonomous systems (AS) on the Internet. BGP is classified as a path-vect ...

blackholing.

Former bogon addresses

IP addresses in the bogon space may cease to be bogons because IANA frequently assigns new address. Announcements of new assignments are often published on

network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

operators'

mailing list A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. Mailing lists are often rented or sold. If rented, the renter agrees to use the mailing list only at contra ...

s (such as NANOG) to ensure that bogon filtering can be removed for addresses that have become legitimate. For example, addresses in were not allocated prior to August 2010, but are now used by

APNIC APNIC (the Asia Pacific Network Information Centre) is the regional Internet address registry ( RIR) for the Asia–Pacific region. It is one of the world's five RIRs and is part of the Number Resource Organization ( NRO). APNIC provides nu ...

. , the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster ...

(IETF) recommends that, since there are no longer any unallocated IPv4 s, IPv4 bogon filters based on registration status should be removed. However, bogon filters still need to check for Martian packets.

References

External links