About Reserved Names
All registry operators are required by their Registry Agreement to exclude certain domain names from registration in a Top Level Domain (TLD). These reserved names include strings that are for Country Code Top Level Domains (ccTLDs), ICANN-related names (such as ICANN), IANA-related names (such as example), and names that the registry operator can use in connection with the operation of the TLD.
A list of reserved names for a registry operator of a TLD in which delegation of second level domain names began before the year 2013 is in Appendix 6 of its Registry Agreement, and in Specification 5 for a registry operator of a TLD in which delegation of second level domain names began during or after the year 2013. ICANN maintains a webpage with all current registry agreements.
ICANN is working with the community to develop a Name Collision Occurrence Management Framework that will be applied to all TLDs delegated into the root zone on and after 2013, which will produce an individual assessment per TLD indicating the mitigating measures that must be applied by the registry. In the interim, such TLDs may choose to proceed to delegation in advance of the forthcoming collision occurrence management by blocking all of the second level domains (SLD) identified in its alternate path to delegation report, if the TLD was found eligible for this measure. The list of SLDs that may be blocked per TLD is available as part of the documents associated with the TLD's registry agreement.
If you have a complaint about reserved names or a blocked SLD, please submit a Reserved and Blocked Second Level Domain (SLD) Names Complaint Form.