AS12942 NRB-AS

Seven small blocks carved out of one /19, with a customer's name showing through the reverse DNS.

What it's used for

• The network of a Belgian IT services company running systems for public sector and utility clients. 2,048 addresses across seven IPv4 prefixes, a single observed BGP neighbour, and no IPv6 announced.

Notable

• Every prefix sits inside 217.117.32.0 through 217.117.63.0, announced as one /23 and six /24s.
• Four blocks carry BE-NRB-20010206 and three carry the bare netname NRB.
• Five of eighteen sampled addresses returned names, including master1-cluster002-bd.nrb.be, 217-117-34-64.nrb.be and portaltst.luminus.be.

Interesting

• One /19 announced as seven separate pieces, with gaps between them. The unannounced parts are either unused or routed somewhere else entirely, and splitting a block this finely is what a company does when different customers' systems need to be moved independently.
• portaltst.luminus.be names a test portal belonging to an energy company. Outsourced hosting leaks the client list through reverse DNS, because each customer wants its own domain on its own systems and nobody thinks of the naming as public disclosure. It usually is.
• master1-cluster002-bd counts a cluster, a node within it, and something abbreviated to two letters. Padding the cluster number to three digits implies planning for a hundred of them.
• The same holder's blocks carry two netname styles, dated and bare, in one contiguous range. Both were created by the same staff object, so the difference is when each record was made rather than any distinction between the blocks.