Attributes of APNIC Whois Database AS number (aut-num) objects
Autonomous System numbers (aut-num objects) are globally unique identifiers for Autonomous Systems. An Autonomous System (AS) is a group of IP networks having a single clearly defined routing policy, run by one or more network operators.
An aut-num object contains details of the organisation delegated the AS number as well as the Autonomous System's routing information.
Using aut-num objects
Use aut-num objects to help configure your network's routers. Aut-num objects, in combination with other routing related objects can be used to describe your routing policy in a compact form. This can help your network identify routing policy errors and omissions more easily than by reading long configuration files.
Use automated tools, such as IRRToolset, to retrieve information from the aut-num objects to create router configuration files for different architectures. Configuration files produced this way should be much less prone to errors than manually configured routers.
Aut-num objects can also be used by network administrators to debug network problems.
aut-num template
To view the aut-num object, see APNIC Whois Database object templates.
AS number (aut-num) attributes
The following describe the mandatory and optional attributes in an aut-num object.
Note: Attributes marked with an asterisk (*) now support four-byte AS number syntax. For more information see the ASN resource guide.
Mandatory attributes
Optional attributes
Attribute |
Function |
Description |
country |
Administrative |
Two letter ISO 3166 code of the country or economy where the admin-c is based. Details of codes are specified in ISO 3166. |
member-of* |
Technical |
Identifies as-set objects of which this aut-num object is intended to be a member. An aut-num may be useful to include in an as-set if your network maintains a number of Autonomous Systems or wishes to include its routes in an upstream provider's routing information. To be included in an as-set, the as-set object must:
Note: do not include an as-set in this attribute if this aut-num is explicitly mentioned in the as-set object's members attribute. Attempts to do so will result in an authorisation failure. For more information on as-set objects, see Attributes of the as-set object. |
import* |
Technical |
The inbound IPv4 routing policy of the AS. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers. The routing policy is specified by a series of expressions that describe peer networks the AS will accept routing information from. Each import attribute lists an AS number or address prefix and may include any costs associated with accepting routing information from that peer. Information in the import attribute must use the following format:
For more information, see RFC 2622, section 6.1. |
mp-import* |
Technical |
This attribute performs the same function as the import attribute above. The difference is that mp-import allows both IPv4 and IPv6 address families to be specified. The inbound IPv4 or IPv6 routing policy of the AS. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers. The routing policy is specified by a series of expressions that describe peer networks the AS will accept routing information from. Each mp-import attribute lists an AS number or address prefix and may include any costs associated with accepting routing information from that peer. Information in the mp-import attribute must use the following format:
For more information, see RFC 4012, section 4.5. New in Whois v3.2. |
export* |
Technical |
The outbound routing policy of the AS. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers. The routing policy is specified by a series of expressions that describe which peer networks the AS will export routing information to. Each export attribute lists an AS number or address prefix. Information in the export attribute must use the following format:
For more information, see RFC 2622, section 6.2. |
mp-export* |
Technical |
This attribute performs the same function as the export attribute above. The difference is that mp-export allows both IPv4 and IPv6 address families to be specified. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers. The routing policy is specified by a series of expressions that describe which peer networks the AS will export routing information to. Each mp-export attribute lists an AS number or address prefix. Information in the mp-export attribute must use the following format:
For more information, see RFC 4012, section 4.5. New in Whois v3.2. |
default* |
Technical |
The peer network the AS will use for as a default, that is, when the AS has no more-specific information on where to send the traffic. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers and you do not have a complex import/export policy. Each default attribute lists an AS number or address prefix and may include a policy filter. Information in the default attribute must use the following format (using multiple lines as necessary):
For more information, see RFC 2622, section 6.5. |
mp-default* |
Technical |
This attribute performs the same function as the default attribute above. The difference is that mp-default allows both IPv4 and IPv6 addresses to be specified. Use this attribute if you plan to use the APNIC Routing Registry to help automate the configuration of your routers and you do not have a complex import/export policy. Each mp-default attribute lists an AS number or address prefix and may include a policy filter. Information in the mp-default attribute must use the following format (using multiple lines as necessary): mp-default: [protocol <protocol-1>] [into <protocol-1>] afi <afi-list> to <mp-peering> [action <action-1>] announce <filter> For more information, see RFC 4012, section 4.5. New in Whois v3.2. |
remarks |
Administrative |
General remarks. May include a URL or email address. |
notify |
Administrative |
The e-mail address to which notifications of changes to an object will be sent. When this attribute contains dbmon@apnic.net, it means APNIC staff are notified of changes to the object. |
mnt-lower |
Administrative |
The identifiers of registered mntner objects used to control the creation of hierarchically named as-set objects that use the name of the aut-num object. If no mnt-lower attribute is listed, mnt-by is referred to when authorising hierarchically named as-set objects. |
mnt-routes |
Administrative |
The identifier of a registered mntner object used to control the creation of route objects that refer to this AS number in the route's origin attribute. |
See also
- Attributes of APNIC Whois Database objects
- Whois v3.2 upgrade guide
- APNIC Routing Registry resource guide
- Updating information in the APNIC Whois Database
- RFC 2622 - Routing Policy Specification Language (RPSL)
- RFC 2650 - Using RPSL in Practice
- RFC 4012 - Routing Policy Specification Language next generation (RPSLng)


