AS39921 DE-RACKSPACE Rackspace Ltd.

DE-RACKSPACE Rackspace Ltd. · registered in the United Kingdom

IPv4 addresses24,8327 prefixes · <0.001% of announced IPv4

Rank in United Kingdom#153largest network in GB by IPv4 space, of 2,074 · 0.04% of GB

Rank worldwide#5,452of 79,396 networks with IPv4

IPv61 x /32 (65,536 x /48)10 prefixes

CountryUnited Kingdom2,261 ASNs registered there

Open AS39921 in ASN lookup Look up an IP in this network (72.21.36.1) All networks in United Kingdom

IPv4 prefixes

All 7 prefixes, in address order.

72.21.36.0/22
147.75.24.0/22
159.135.80.0/20
159.135.128.0/18
185.16.216.0/22
185.205.104.0/22
192.68.42.0/24

IPv6 prefixes

All 10 prefixes.

2a0b:440::/37
2a0b:440:800::/41
2a0b:440:880::/41
2a0b:440:900::/40
2a0b:440:a00::/39
2a0b:440:c00::/38
2a0b:440:1000::/36
2a0b:440:2000::/35
2a0b:440:4000::/34
2a0b:440:8000::/33

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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