AS15541 — CETI-AS CETI ISP, Poland

Network type: hosting

AS15541 announces 12 IPv4 prefixes covering 4,608 addresses and 0 IPv6 prefixes.

About this network

Seventeen of eighteen addresses answer, and the two exceptions sit on a different domain.

What it's used for

• A regional internet provider. Twelve IPv4 prefixes announced from Poland, no IPv6, four and a half thousand addresses, across nine observed BGP neighbours.

Notable

• Fifteen answering addresses use one form: a two-letter prefix, the address in dashes, and a three-label domain.
• The two exceptions use a shorter domain instead. One names an ethernet interface on a host; the other is a virtual host, with the third and last octets run together into a single number with no separator.
• Eleven of the twelve blocks share one netname and one allocation date; the twelfth substitutes its own third octet for the date and drops the company from its registrant list.
• The block is held by an individual trading as a partnership, so the registrant is a person rather than a company.
• Eighteen addresses were queried for reverse DNS and seventeen returned a name.

Interesting

• Running the third and last octet together produces a number that reads as one value but is two. It works because the operator knows the convention, and it is unparseable to anyone who does not.
• Two domains in one zone, with infrastructure on the short one and customers on the long one, is a sensible split: it keeps the routers findable by people who need them and everything else generic.
• Twelve routes from one contiguous range, none of them adjacent enough to merge, is the fragmentation that comes from growing a /24 at a time.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 62.121.128.0/22
• 62.121.132.0/23
• 62.121.135.0/24
• 62.121.136.0/24
• 62.121.138.0/24
• 62.121.141.0/24
• 62.121.142.0/23
• 62.121.144.0/23
• 62.121.146.0/24
• 62.121.148.0/24
• 62.121.150.0/24
• 62.121.152.0/24

Upstream networks

• AS9141 P4 Sp. z o.o.
• AS42927 S-NET Sp. z o.o.
• AS33891 Core-Backbone GmbH
• AS24482 SG.GS
• AS6939 Hurricane Electric LLC

Downstream networks

• AS44732 Zwiazek Centralny Dziela Kolpinga w Polsce
• AS29593 WOJCIECH LOREK ENDOR COMPUTERS

Adjacent networks

• AS9141 P4 Sp. z o.o.
• AS42927 S-NET Sp. z o.o.
• AS33891 Core-Backbone GmbH
• AS6939 Hurricane Electric LLC
• AS24482 SG.GS
• AS44732 Zwiazek Centralny Dziela Kolpinga w Polsce
• AS29593 WOJCIECH LOREK ENDOR COMPUTERS

Internet exchanges

• TPIX - Internet Exchange — Warsaw, Poland