AS21369 — SEMA-UK-AS

AS21369 announces 12 IPv4 prefixes covering 8,704 addresses and 0 IPv6 prefixes.

About this network

SEMA-UK-AS is held by Atos IT Services UK Ltd.

What it's used for

• The address space carries corporate IT infrastructure, evidenced by reverse DNS entries pointing to uk.atosorigin.com and netnames like UK-ATOSUK-20070407.
• The AS announces 8704 IPv4 addresses across 15 prefixes with only 4 observed neighbours, indicating a small internal corporate estate rather than a transit or access network.

Notable

• All registrants for the largest prefixes are consistent with the announcer, listing ATOS Admin and Atos IT Services UK Ltd.
• Atos is a European multinational IT service and consulting company; this AS represents its UK operational footprint.
• The inventory consists of finely subdivided /22, /23, and /24 blocks within the 157.203.0.0/16 range, typical of site-by-site corporate segmentation.

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

Announced prefixes

• 157.203.6.0/23
• 157.203.36.0/23
• 157.203.40.0/22
• 157.203.48.0/23
• 157.203.52.0/23
• 157.203.56.0/21
• 157.203.92.0/23
• 157.203.120.0/23
• 157.203.176.0/22
• 157.203.180.0/23
• 157.203.242.0/23
• 157.203.254.0/23

Upstream networks

• AS198949 Radware Ltd
• AS8220 COLT Technology Services Group Limited
• AS2856 British Telecommunications Limited
• AS702 Verizon Business

Adjacent networks

• AS198949 Radware Ltd
• AS8220 COLT Technology Services Group Limited
• AS2856 British Telecommunications Limited
• AS702 Verizon Business