LACNIC's WHOIS service allows querying information on the Autonomous System Numbers (ASNs) and IP addresses assigned by LACNIC.

The Whois service is a distributed information system that allows for querying Internet resources to obtain information on IP address or domain name holders.

LACNIC's Whois service allows for querying information on Autonomous System Numbers and IP address blocks assigned by LACNIC. In addition, it allows for obtaining information related to these Internet resources, such as contact information for the organizations that hold them.


The Whois system was originally described in RFC 812, which was later made obsolete by RFC 3912 – "Whois Protocol Specification." As described in these documents, the original Whois system was designed as a tool for querying the points of contact of organizations that were connected to the ARPANET at the time. The system does not specify which format should be used in the answers to the queries it receives. Therefore, different Whois servers provide information in different formats.

How should queries be performed?

The server can be queried in two different ways:

  • From a computer where the Whois client software is installed, using a command line interface and the following syntax: whois -h
  • Through LACNIC's Web Site at

The information provided by LACNIC's Whois service is organized as a list of values and attributes separated by a ":" character.
When querying resources, either ASNs or IP address blocks, the answer returned includes, among others, the following attributes:

  • "owner:" Name of the organization holding the queried resource;
  • "ownerid:" The organization's handle in LACNIC's database;
  • "responsable:" Name of the organization's point of contact (person or group);
  • "address:" The organization's postal address;
  • "country:" The organization's country code;
  • "phone:" The organization's telephone number;
  • "owner-c:" Database handle of the organization's point of contact;
  • "tech-c:" Handle of the IP block's technical point of contact;
  • "routing-c:" Handle of the ASN's technical point of contact;
  • "abuse-c:" Handle of the organization's abuse contact;
  • "created:" Date on which the Internet resource was assigned;
  • "changed:" Date on which the resource's data was last modified.

The point-of-contact information associated with this Internet resource is then presented. Returned attributes include:

  • "nic-hdl:" Point of contact's handle in LACNIC's database;
  • "person:" Name of the person or group representing this point of contact;
  • "e-mail:" Point of contact's email address;
  • "address:" Point of contact's postal address;
  • "country:" Point of contact's country code;
  • "phone:" Point of contact's telephone number;
  • "created:" Date when the record was created in LACNIC's database;
  • "changed:" Date when the point of contact's data was last modified.

When an IP block is queried, in addition to the attributes described above, there may also be DNS reverse delegation data available. Its attributes are as follows:

  • "inetrev:" Specifies the complete or partial block that was delegated;
  • "nserver:" DNS server name;
  • "nsstat:" Status of this DNS server;
  • "nslastaa:" Date when an "ok" status was last obtained for this server.

Even in the case of queries for IP address blocks that have been sub-assigned to other organizations, the data returned will refer to the sub-assignment's parent block, that is the original block from which the sub-assignment was made. In this case, "inetnum-up" is the attribute that is used.

In addition to ASN or IP address block queries, LACNIC's Whois system allows querying by point of contact handles. In this case the system will only return the point of contact's name, postal address, email and telephone number.

Finally, LACNIC's Whois system also allows querying by organization handles. In addition to the information mentioned above, the answer to this type of query will also include a list of all the Internet resources assigned to this organization. The attributes for this query are as follows:

  • "aut-num:" ASN assigned to the organization;
  • "inetnum:" IPv4 or IPv6 address block assigned to the organization.

Joint Whois

Joint Whois is a project carried out by the five RIRs under the coordination of the Number Resource Organization (NRO) that aims at having a single entry point for all queries, regardless of the RIR holding the queried resources.

Currently, each RIR operates its own Whois query service which allows for obtaining information about the Internet resources assigned by each RIR to organizations located in their own service regions.

This presents a problem for users: before searching for information about a resource they must first identify which RIR is responsible for the resource in question and then proceed to perform the Whois query against the corresponding RIR. To avoid this issue and make this procedure easier to use, working under NRO coordination the Regional Registries have developed the Joint Whois service. This service provides a single point of entry for queries about any Internet resource regardless of the RIR to which the resources belong.

The Joint Whois system is basically a "proxy" that redirects the queries it receives towards the Whois server of the RIR holding the resource. When an RIR's server receives a query, it will identify the RIR responsible for the assignment and will immediately redirect the Whois query to that RIR. The answer will then be forwarded to the user.
Currently, the server operates as a Joint Whois proxy.