AS7786 NPAC

Neustar's network, now registered to Trans Union, LLC. The ARIN object carries the

NEUSTAR-AS1 name; older listings show the handle NPAC, after the Number

Portability Administration Center that Neustar ran for the US telephone industry.

What it's used for

• Neustar's own service and corporate infrastructure. Reverse DNS across the announced 156.154.0.0 space lands almost entirely on neustar.biz and neulevel.biz hosts — registry, DNS, transfer and test systems rather than customer access networks.
• The address space is a cluster of /24s and /23s carved out of one legacy block, the shape of a company numbering its own services, not selling connectivity.

Notable

• The NPAC handle outlived the role: administration of US number portability moved away from Neustar in 2018, but the registry object kept the name.
• Neustar was acquired by TransUnion in 2021, which is why the ASN's registrant is a credit bureau rather than a telecom company. The name on the AS and the business behind it have drifted apart twice over.

Interesting

• Neustar's 156.154.0.0 space is best known publicly for its recursive DNS resolvers, so hosts in this range are often mistaken for a consumer service; the bulk of what this AS announces is back-office and registry infrastructure.