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AS112 Service

INEX operates an AS112 service.  This system provides anycast reverse DNS lookup for several prefixes, namely:


Because these IP addresses are widely used for private networking, many end-user systems are configured to perform reverse DNS lookups for these address ranges.  DNS lookups for these ranges should always be null-answered quickly, in order to make sure that DNS retransmits don’t occur (thereby overloading local DNS resolvers), and to prevent end-user systems from hanging due to DNS lookups.

AS112 services are provided around the world by a group of volunteers.

Connectivity to this service is available to all INEX members at no charge.  To avail of this service, please contact INEX operations, and we will set up a BGP peering session on the INEX AS112 server.

Technical contact, NOC and emergency phone numbers are the same as for INEX Operations, and are available on www.inex.ie/members/support.

Configuration Details

For Cisco routers, you will need something like the following simple example BGP configuration for primary peering LAN #1:

router bgp 64496
  ! INEX Peering LAN #1
  neighbor remote-as 112
  neighbor description INEX AS112 Service
  neighbor 2001:7f8:18::6 remote-as 112
  neighbor 2001:7f8:18::6 description INEX AS112 Service
  address-family ipv4
    neighbor activate
    neighbor prefix-list pl-v4-announce-to-inex out
  address-family ipv6
    neighbor 2001:7f8:18::6 activate
    neighbor 2001:7f8:18::6 prefix-list pl-v6-announce-to-inex out

Technical Details

INEX operates two AS112 instances on a virtual machine (one running on XenServer, the other ESXi), using BIND 9.10 on Ubuntu LTS 16.04.

One instance is located in Dublin serving INEX’s primary peering LAN1 and primary peering LAN2. The second is located in Cork serving the INEX Cork LAN. Public statistics are available for for the instance in Dublin and for the instance in INEX Cork.

They conform to rfc7534 (AS112 Nameserver Operations) and implement rfc7535 (AS112 Redirection Using DNAME). They both serve queries over both IPv4 and IPv6.

Contact INEX Operations to arrange peering sessions. While both AS112 instances also peer with all INEX route servers, bilateral peering is also recommended.

The peering addresses and looking glasses for the different AS112 instances are:


  • LAN1 IPv4: (LG)
  • LAN1 IPv6: 2001:7f8:18::6 (LG)
  • LAN2 IPv4: (LG)
  • LAN2 IPv6: 2001:7f8:18:12::6 (LG)


  • IPv4: (LG)
  • IPv6: 2001:7f8:18:210::6 (LG)