AS21369 SEMA-UK-AS Atos IT Services UK Ltd

SEMA-UK-AS Atos IT Services UK Ltd · registered in the United Kingdom

IPv4 addresses8,70415 prefixes · <0.001% of announced IPv4

Rank in United Kingdom#324largest network in GB by IPv4 space, of 2,074 · 0.01% of GB

Rank worldwide#9,939of 79,396 networks with IPv4

IPv6noneno IPv6 routes announced

CountryUnited Kingdom2,261 ASNs registered there

Open AS21369 in ASN lookup Look up an IP in this network (157.203.6.1) All networks in United Kingdom

IPv4 prefixes

All 15 prefixes, in address order.

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
157.203.56.0/22
157.203.60.0/23
157.203.62.0/24
157.203.63.0/24
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

Similar-sized networks in United Kingdom

ASNNameIPv4 addresses

AS13002#321 ISIX-AS ISIX Communications LLP8,704

AS42010#322 ITPS I.T. PROFESSIONAL SERVICES LIMITED8,704

AS43519#323 NOMINETANYCAST Nominet UK8,704

AS29676#325 GRADWELL Gradwell Communications Limited8,704

AS199775#326 Connexin-Limited Connexin Limited8,704

AS52148#327 ENIXLTD Enix Ltd8,448

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources