The Team Cymru IPv4 Full Bogons Blacklist is an IP-based blocklist (blacklist) containing 'bogon' IP addresses, which are addresses that have not been allocated or are reserved and should not be seen on the public internet.
The Team Cymru IPv4 Full Bogons Blacklist, identified by the zone name v4.fullbogons.cymru.com, is a specialized IP-based blocklist. It does not list IPs based on spamming activity. Instead, this blacklist tracks "bogons", which are IP addresses that are invalid, unassigned, or should not be routed on the public internet.
Bogon filtering is a security practice used to block network traffic from these unallocated IP address ranges. These addresses are often exploited for malicious activities such as DDoS attacks or IP spoofing. By using a bogon blocklist, networks can add a layer of security by dropping traffic from these illegitimate sources at their network perimeter.
Technically, when a system queries this DNS-based blacklist (DNSBL) with an IP address, it gets a specific response if the IP is a bogon. A listed IP address will return an A record of 127.0.0.2. It is important for network administrators to understand that this list can have negative effects if not applied correctly, as it is not a simple spam filter.
The Team Cymru IPv4 Full Bogons Blacklist is operated and maintained by Team Cymru, an organization focused on internet security and threat intelligence.
It is not possible to request delisting or removal from the Team Cymru IPv4 Full Bogons Blacklist. This is because it is not a list of 'bad' IPs but rather a list of IP addresses that are not yet registered for use on the public internet. If your IP is listed, it is likely due to one of two reasons: the IP is genuinely unallocated, or it is a private IP address not meant for public internet traffic.
Often, being blocked by a system using this list is a sign of a misconfiguration. A network administrator may have incorrectly applied this bogon list to a system like an email server, thinking it was a traditional spam blacklist. If you are being blocked, you should:
Team Cymru cannot 'unblock' you because they do not control the systems that are using their data. The responsibility lies with the administrator of the system that is implementing the blocklist.
The impact of being listed on this blacklist (or blocklist) is generally considered low for legitimate internet traffic. A listing simply means an IP address is unassigned or reserved. Since valid public internet services and email servers should not be using these IP addresses, a correctly configured system would not be affected.
However, the impact can become significant if a network administrator misuses the list, for example, by applying it as a generic email filter. In such cases, it could block traffic from internal networks or cause other unintended filtering issues. The primary negative impact arises from incorrect implementation, not from the listing itself.
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