Definition of Bogon

A bogon is a term used in networking to refer to an illegitimate IP address or a packet with a bogus routing prefix. These addresses are either reserved, unallocated, or used for a private network and should not appear in public internet traffic. Filtering bogons helps network administrators prevent spam, distributed denial-of-service (DDoS) attacks, and other malicious activities.


The phonetic pronunciation of the keyword “Bogon” is: /ˈbəʊɡɒn/

Key Takeaways

  1. Bogons are IP addresses that should not appear in Internet routing tables, as they are either reserved for special-use, private networks, or not yet assigned by IANA.
  2. By filtering and restricting access to Bogon IP addresses, network administrators can protect their systems against unauthorized traffic, spam, and various cyber threats.
  3. Team Cymru’s Bogon Reference provides an up-to-date list of all known Bogon IP addresses, which can be used to keep network filters current and effective in preventing unwanted traffic.

Importance of Bogon

The term “Bogon” is important in technology because it refers to an illegitimate or fake IP address that can be maliciously used to enable cyberattacks.

Bogons usually originate from unallocated or reserved IP address spaces that should not be present in the internet routing table.

By detecting and filtering Bogon addresses, network administrators can protect their systems from potential threats, such as Distributed Denial of Service (DDoS) attacks, data theft, and other forms of cybercrime.

Thus, understanding and addressing Bogons is essential for maintaining the security and integrity of networks and infrastructure in the ever-evolving digital landscape.


Bogon is a term used in the field of computer networking and internet security to refer to an IP address that is either reserved, unallocated, or simply illegitimate. The primary purpose of identifying and tracking Bogons is to protect the integrity and smooth functioning of the internet from potential cyber threats, such as spamming, hacking, and denial-of-service (DoS) attacks.

Bogons can also be used by malicious actors to impersonate legitimate users or launch cyber-attacks that are difficult to trace and mitigate. Consequently, network administrators and cybersecurity professionals closely monitor Bogon IP addresses to strengthen the defenses of their networks and keep unwarranted activities at bay.

In order to effectively manage the risks posed by Bogons, Internet Service Providers (ISPs) and organizations implement tools and processes, such as Bogon filtering and route filtering. Bogon filtering involves blocking traffic from Bogon IP addresses on routers and firewalls to limit their access and potential impact on a network.

Route filtering, on the other hand, prevents the propagation of illegitimate BGPs (Border Gateway Protocols) that may be associated with Bogon IP addresses. By being proactive in identifying and filtering Bogons, network administrators can maintain a high level of internet security, ensure proper allocation of IP addresses, and uphold the overall performance and reliability of online services.

Examples of Bogon

A “bogon” is a term in networking that refers to an illegitimate IP address or a packet containing an illegitimate IP address, which should not appear in the public Internet. Here are three real-world examples of Bogon IP addresses usage in technology:

Filtering bogons for network security: Many firewalls and intrusion detection systems (IDS) use bogon lists to block traffic from suspicious IP addresses. By filtering out these bogus IP addresses from inbound and outbound traffic, organizations can prevent unauthorized access, malicious activities, and even Distributed Denial of Service (DDoS) attacks from illegitimate IP addresses.

Internet service providers (ISPs) and the Border Gateway Protocol (BGP): ISPs use bogon lists to filter out illegitimate IP prefixes from BGP announcements, ensuring that only valid IP prefixes are propagated to the Internet routing table. This helps maintain the stability of the Internet infrastructure and prevents accidental or malicious propagation of invalid routes.

Bogon research and tracking initiatives: To better understand and respond to the threat of bogons, numerous organizations and individuals dedicate their efforts to researching and tracking bogon IP addresses. For example, the Team Cymru Bogon Reference and the Spamhaus DROP list both provide extensive information on bogon IP addresses and their potential impact on the Internet infrastructure. By staying up to date with the latest bogon lists, network administrators can keep their organizations secure from potential threats.

Bogon FAQ

1. What is a Bogon?

A Bogon is an IP address, IP range or Autonomous System Number (ASN) that is not assigned to any organization, and should not be routable on the internet. Bogons are commonly observed in anomalous or malicious network activity.

2. Why should Bogon addresses be filtered?

Filtering Bogon addresses helps to prevent malicious or inappropriate use of unassigned network resources. Blocking Bogon traffic can help protect your network against DDoS attacks, spamming, and scanning activities as well as conserving network resources.

3. How do I identify and filter Bogon addresses?

Bogon lists are maintained by organizations like Team Cymru and IANA, which provide regularly updated listings of Bogon IP addresses that you can use for filtering purposes. You can use these lists to configure firewalls, routers or other security devices to block traffic from these addresses.

4. What is the difference between a Bogon and a Martian address?

Bogon addresses encompass unallocated IP address space, while Martian addresses are reserved IP addresses for special-use purposes and should not be routable on the public Internet. Martian addresses include addresses like loopback and private IPv4 address ranges like,, and

5. Are Bogon addresses harmful?

Not necessarily. Bogon addresses themselves are not harmful, but they can be used for malicious purposes if they appear in traffic on the internet. Bogon filtering helps protect against this by blocking connections from these invalid addresses.

Related Technology Terms

  • Bogon Filtering
  • IP Spoofing
  • Internet Routing Registries (IRR)
  • Martian packets
  • Border Gateway Protocol (BGP)

Sources for More Information


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