Speed and call quality testMy IP addressIP subnet calculatorDNS reportWhoIs lookupRemote support

Internet and network

Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

Computers and devices

Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

Make and print

Clean textStrip hidden characters, smart quotes and odd spaces from pasted text.QR code makerMake a QR code for a link, contact or message. Nothing leaves your browser.Wi-Fi QR posterPrint an A4 poster that lets guests join your Wi-Fi by scanning.

Surftec support

Remote supportLet a Surftec engineer connect to your computer to help you.All workingA full-screen confirmation that everything is up and running.

Surftec

Surftec websiteServices, news and how to contact Surftec
Cloud Tools
Guest
GuestNot signed in

Surftec customers will be recognised automatically when they use these tools from their office network.

Customer sign-in is coming soon.

IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Prefix/120
Addresses256
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:94de:b900/120
First address
2c19:dd:d9:dd:c25:c25:94de:b900
Last address
2c19:dd:d9:dd:c25:c25:94de:b9ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:b900
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
9.b.e.d.4.9.5.2.c.0.5.2.c.0.d.d.0.0.9.d.0.0.d.d.0.0.9.1.c.2.ip6.arpa
Split into smaller subnets/128
/121 (2)/122 (4)/123 (8)/124 (16)/127 (128)/128 (256)

2c19:dd:d9:dd:c25:c25:94de:b900/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:b900/1282c19:dd:d9:dd:c25:c25:94de:b900
22c19:dd:d9:dd:c25:c25:94de:b901/1282c19:dd:d9:dd:c25:c25:94de:b901
32c19:dd:d9:dd:c25:c25:94de:b902/1282c19:dd:d9:dd:c25:c25:94de:b902
42c19:dd:d9:dd:c25:c25:94de:b903/1282c19:dd:d9:dd:c25:c25:94de:b903
52c19:dd:d9:dd:c25:c25:94de:b904/1282c19:dd:d9:dd:c25:c25:94de:b904
62c19:dd:d9:dd:c25:c25:94de:b905/1282c19:dd:d9:dd:c25:c25:94de:b905
72c19:dd:d9:dd:c25:c25:94de:b906/1282c19:dd:d9:dd:c25:c25:94de:b906
82c19:dd:d9:dd:c25:c25:94de:b907/1282c19:dd:d9:dd:c25:c25:94de:b907
92c19:dd:d9:dd:c25:c25:94de:b908/1282c19:dd:d9:dd:c25:c25:94de:b908
102c19:dd:d9:dd:c25:c25:94de:b909/1282c19:dd:d9:dd:c25:c25:94de:b909
112c19:dd:d9:dd:c25:c25:94de:b90a/1282c19:dd:d9:dd:c25:c25:94de:b90a
122c19:dd:d9:dd:c25:c25:94de:b90b/1282c19:dd:d9:dd:c25:c25:94de:b90b
132c19:dd:d9:dd:c25:c25:94de:b90c/1282c19:dd:d9:dd:c25:c25:94de:b90c
142c19:dd:d9:dd:c25:c25:94de:b90d/1282c19:dd:d9:dd:c25:c25:94de:b90d
152c19:dd:d9:dd:c25:c25:94de:b90e/1282c19:dd:d9:dd:c25:c25:94de:b90e
162c19:dd:d9:dd:c25:c25:94de:b90f/1282c19:dd:d9:dd:c25:c25:94de:b90f
172c19:dd:d9:dd:c25:c25:94de:b910/1282c19:dd:d9:dd:c25:c25:94de:b910
182c19:dd:d9:dd:c25:c25:94de:b911/1282c19:dd:d9:dd:c25:c25:94de:b911
192c19:dd:d9:dd:c25:c25:94de:b912/1282c19:dd:d9:dd:c25:c25:94de:b912
202c19:dd:d9:dd:c25:c25:94de:b913/1282c19:dd:d9:dd:c25:c25:94de:b913
212c19:dd:d9:dd:c25:c25:94de:b914/1282c19:dd:d9:dd:c25:c25:94de:b914
222c19:dd:d9:dd:c25:c25:94de:b915/1282c19:dd:d9:dd:c25:c25:94de:b915
232c19:dd:d9:dd:c25:c25:94de:b916/1282c19:dd:d9:dd:c25:c25:94de:b916
242c19:dd:d9:dd:c25:c25:94de:b917/1282c19:dd:d9:dd:c25:c25:94de:b917
252c19:dd:d9:dd:c25:c25:94de:b918/1282c19:dd:d9:dd:c25:c25:94de:b918
262c19:dd:d9:dd:c25:c25:94de:b919/1282c19:dd:d9:dd:c25:c25:94de:b919
272c19:dd:d9:dd:c25:c25:94de:b91a/1282c19:dd:d9:dd:c25:c25:94de:b91a
282c19:dd:d9:dd:c25:c25:94de:b91b/1282c19:dd:d9:dd:c25:c25:94de:b91b
292c19:dd:d9:dd:c25:c25:94de:b91c/1282c19:dd:d9:dd:c25:c25:94de:b91c
302c19:dd:d9:dd:c25:c25:94de:b91d/1282c19:dd:d9:dd:c25:c25:94de:b91d
312c19:dd:d9:dd:c25:c25:94de:b91e/1282c19:dd:d9:dd:c25:c25:94de:b91e
322c19:dd:d9:dd:c25:c25:94de:b91f/1282c19:dd:d9:dd:c25:c25:94de:b91f
332c19:dd:d9:dd:c25:c25:94de:b920/1282c19:dd:d9:dd:c25:c25:94de:b920
342c19:dd:d9:dd:c25:c25:94de:b921/1282c19:dd:d9:dd:c25:c25:94de:b921
352c19:dd:d9:dd:c25:c25:94de:b922/1282c19:dd:d9:dd:c25:c25:94de:b922
362c19:dd:d9:dd:c25:c25:94de:b923/1282c19:dd:d9:dd:c25:c25:94de:b923
372c19:dd:d9:dd:c25:c25:94de:b924/1282c19:dd:d9:dd:c25:c25:94de:b924
382c19:dd:d9:dd:c25:c25:94de:b925/1282c19:dd:d9:dd:c25:c25:94de:b925
392c19:dd:d9:dd:c25:c25:94de:b926/1282c19:dd:d9:dd:c25:c25:94de:b926
402c19:dd:d9:dd:c25:c25:94de:b927/1282c19:dd:d9:dd:c25:c25:94de:b927
412c19:dd:d9:dd:c25:c25:94de:b928/1282c19:dd:d9:dd:c25:c25:94de:b928
422c19:dd:d9:dd:c25:c25:94de:b929/1282c19:dd:d9:dd:c25:c25:94de:b929
432c19:dd:d9:dd:c25:c25:94de:b92a/1282c19:dd:d9:dd:c25:c25:94de:b92a
442c19:dd:d9:dd:c25:c25:94de:b92b/1282c19:dd:d9:dd:c25:c25:94de:b92b
452c19:dd:d9:dd:c25:c25:94de:b92c/1282c19:dd:d9:dd:c25:c25:94de:b92c
462c19:dd:d9:dd:c25:c25:94de:b92d/1282c19:dd:d9:dd:c25:c25:94de:b92d
472c19:dd:d9:dd:c25:c25:94de:b92e/1282c19:dd:d9:dd:c25:c25:94de:b92e
482c19:dd:d9:dd:c25:c25:94de:b92f/1282c19:dd:d9:dd:c25:c25:94de:b92f
492c19:dd:d9:dd:c25:c25:94de:b930/1282c19:dd:d9:dd:c25:c25:94de:b930
502c19:dd:d9:dd:c25:c25:94de:b931/1282c19:dd:d9:dd:c25:c25:94de:b931
512c19:dd:d9:dd:c25:c25:94de:b932/1282c19:dd:d9:dd:c25:c25:94de:b932
522c19:dd:d9:dd:c25:c25:94de:b933/1282c19:dd:d9:dd:c25:c25:94de:b933
532c19:dd:d9:dd:c25:c25:94de:b934/1282c19:dd:d9:dd:c25:c25:94de:b934
542c19:dd:d9:dd:c25:c25:94de:b935/1282c19:dd:d9:dd:c25:c25:94de:b935
552c19:dd:d9:dd:c25:c25:94de:b936/1282c19:dd:d9:dd:c25:c25:94de:b936
562c19:dd:d9:dd:c25:c25:94de:b937/1282c19:dd:d9:dd:c25:c25:94de:b937
572c19:dd:d9:dd:c25:c25:94de:b938/1282c19:dd:d9:dd:c25:c25:94de:b938
582c19:dd:d9:dd:c25:c25:94de:b939/1282c19:dd:d9:dd:c25:c25:94de:b939
592c19:dd:d9:dd:c25:c25:94de:b93a/1282c19:dd:d9:dd:c25:c25:94de:b93a
602c19:dd:d9:dd:c25:c25:94de:b93b/1282c19:dd:d9:dd:c25:c25:94de:b93b
612c19:dd:d9:dd:c25:c25:94de:b93c/1282c19:dd:d9:dd:c25:c25:94de:b93c
622c19:dd:d9:dd:c25:c25:94de:b93d/1282c19:dd:d9:dd:c25:c25:94de:b93d
632c19:dd:d9:dd:c25:c25:94de:b93e/1282c19:dd:d9:dd:c25:c25:94de:b93e
642c19:dd:d9:dd:c25:c25:94de:b93f/1282c19:dd:d9:dd:c25:c25:94de:b93f
652c19:dd:d9:dd:c25:c25:94de:b940/1282c19:dd:d9:dd:c25:c25:94de:b940
662c19:dd:d9:dd:c25:c25:94de:b941/1282c19:dd:d9:dd:c25:c25:94de:b941
672c19:dd:d9:dd:c25:c25:94de:b942/1282c19:dd:d9:dd:c25:c25:94de:b942
682c19:dd:d9:dd:c25:c25:94de:b943/1282c19:dd:d9:dd:c25:c25:94de:b943
692c19:dd:d9:dd:c25:c25:94de:b944/1282c19:dd:d9:dd:c25:c25:94de:b944
702c19:dd:d9:dd:c25:c25:94de:b945/1282c19:dd:d9:dd:c25:c25:94de:b945
712c19:dd:d9:dd:c25:c25:94de:b946/1282c19:dd:d9:dd:c25:c25:94de:b946
722c19:dd:d9:dd:c25:c25:94de:b947/1282c19:dd:d9:dd:c25:c25:94de:b947
732c19:dd:d9:dd:c25:c25:94de:b948/1282c19:dd:d9:dd:c25:c25:94de:b948
742c19:dd:d9:dd:c25:c25:94de:b949/1282c19:dd:d9:dd:c25:c25:94de:b949
752c19:dd:d9:dd:c25:c25:94de:b94a/1282c19:dd:d9:dd:c25:c25:94de:b94a
762c19:dd:d9:dd:c25:c25:94de:b94b/1282c19:dd:d9:dd:c25:c25:94de:b94b
772c19:dd:d9:dd:c25:c25:94de:b94c/1282c19:dd:d9:dd:c25:c25:94de:b94c
782c19:dd:d9:dd:c25:c25:94de:b94d/1282c19:dd:d9:dd:c25:c25:94de:b94d
792c19:dd:d9:dd:c25:c25:94de:b94e/1282c19:dd:d9:dd:c25:c25:94de:b94e
802c19:dd:d9:dd:c25:c25:94de:b94f/1282c19:dd:d9:dd:c25:c25:94de:b94f
812c19:dd:d9:dd:c25:c25:94de:b950/1282c19:dd:d9:dd:c25:c25:94de:b950
822c19:dd:d9:dd:c25:c25:94de:b951/1282c19:dd:d9:dd:c25:c25:94de:b951
832c19:dd:d9:dd:c25:c25:94de:b952/1282c19:dd:d9:dd:c25:c25:94de:b952
842c19:dd:d9:dd:c25:c25:94de:b953/1282c19:dd:d9:dd:c25:c25:94de:b953
852c19:dd:d9:dd:c25:c25:94de:b954/1282c19:dd:d9:dd:c25:c25:94de:b954
862c19:dd:d9:dd:c25:c25:94de:b955/1282c19:dd:d9:dd:c25:c25:94de:b955
872c19:dd:d9:dd:c25:c25:94de:b956/1282c19:dd:d9:dd:c25:c25:94de:b956
882c19:dd:d9:dd:c25:c25:94de:b957/1282c19:dd:d9:dd:c25:c25:94de:b957
892c19:dd:d9:dd:c25:c25:94de:b958/1282c19:dd:d9:dd:c25:c25:94de:b958
902c19:dd:d9:dd:c25:c25:94de:b959/1282c19:dd:d9:dd:c25:c25:94de:b959
912c19:dd:d9:dd:c25:c25:94de:b95a/1282c19:dd:d9:dd:c25:c25:94de:b95a
922c19:dd:d9:dd:c25:c25:94de:b95b/1282c19:dd:d9:dd:c25:c25:94de:b95b
932c19:dd:d9:dd:c25:c25:94de:b95c/1282c19:dd:d9:dd:c25:c25:94de:b95c
942c19:dd:d9:dd:c25:c25:94de:b95d/1282c19:dd:d9:dd:c25:c25:94de:b95d
952c19:dd:d9:dd:c25:c25:94de:b95e/1282c19:dd:d9:dd:c25:c25:94de:b95e
962c19:dd:d9:dd:c25:c25:94de:b95f/1282c19:dd:d9:dd:c25:c25:94de:b95f
972c19:dd:d9:dd:c25:c25:94de:b960/1282c19:dd:d9:dd:c25:c25:94de:b960
982c19:dd:d9:dd:c25:c25:94de:b961/1282c19:dd:d9:dd:c25:c25:94de:b961
992c19:dd:d9:dd:c25:c25:94de:b962/1282c19:dd:d9:dd:c25:c25:94de:b962
1002c19:dd:d9:dd:c25:c25:94de:b963/1282c19:dd:d9:dd:c25:c25:94de:b963
1012c19:dd:d9:dd:c25:c25:94de:b964/1282c19:dd:d9:dd:c25:c25:94de:b964
1022c19:dd:d9:dd:c25:c25:94de:b965/1282c19:dd:d9:dd:c25:c25:94de:b965
1032c19:dd:d9:dd:c25:c25:94de:b966/1282c19:dd:d9:dd:c25:c25:94de:b966
1042c19:dd:d9:dd:c25:c25:94de:b967/1282c19:dd:d9:dd:c25:c25:94de:b967
1052c19:dd:d9:dd:c25:c25:94de:b968/1282c19:dd:d9:dd:c25:c25:94de:b968
1062c19:dd:d9:dd:c25:c25:94de:b969/1282c19:dd:d9:dd:c25:c25:94de:b969
1072c19:dd:d9:dd:c25:c25:94de:b96a/1282c19:dd:d9:dd:c25:c25:94de:b96a
1082c19:dd:d9:dd:c25:c25:94de:b96b/1282c19:dd:d9:dd:c25:c25:94de:b96b
1092c19:dd:d9:dd:c25:c25:94de:b96c/1282c19:dd:d9:dd:c25:c25:94de:b96c
1102c19:dd:d9:dd:c25:c25:94de:b96d/1282c19:dd:d9:dd:c25:c25:94de:b96d
1112c19:dd:d9:dd:c25:c25:94de:b96e/1282c19:dd:d9:dd:c25:c25:94de:b96e
1122c19:dd:d9:dd:c25:c25:94de:b96f/1282c19:dd:d9:dd:c25:c25:94de:b96f
1132c19:dd:d9:dd:c25:c25:94de:b970/1282c19:dd:d9:dd:c25:c25:94de:b970
1142c19:dd:d9:dd:c25:c25:94de:b971/1282c19:dd:d9:dd:c25:c25:94de:b971
1152c19:dd:d9:dd:c25:c25:94de:b972/1282c19:dd:d9:dd:c25:c25:94de:b972
1162c19:dd:d9:dd:c25:c25:94de:b973/1282c19:dd:d9:dd:c25:c25:94de:b973
1172c19:dd:d9:dd:c25:c25:94de:b974/1282c19:dd:d9:dd:c25:c25:94de:b974
1182c19:dd:d9:dd:c25:c25:94de:b975/1282c19:dd:d9:dd:c25:c25:94de:b975
1192c19:dd:d9:dd:c25:c25:94de:b976/1282c19:dd:d9:dd:c25:c25:94de:b976
1202c19:dd:d9:dd:c25:c25:94de:b977/1282c19:dd:d9:dd:c25:c25:94de:b977
1212c19:dd:d9:dd:c25:c25:94de:b978/1282c19:dd:d9:dd:c25:c25:94de:b978
1222c19:dd:d9:dd:c25:c25:94de:b979/1282c19:dd:d9:dd:c25:c25:94de:b979
1232c19:dd:d9:dd:c25:c25:94de:b97a/1282c19:dd:d9:dd:c25:c25:94de:b97a
1242c19:dd:d9:dd:c25:c25:94de:b97b/1282c19:dd:d9:dd:c25:c25:94de:b97b
1252c19:dd:d9:dd:c25:c25:94de:b97c/1282c19:dd:d9:dd:c25:c25:94de:b97c
1262c19:dd:d9:dd:c25:c25:94de:b97d/1282c19:dd:d9:dd:c25:c25:94de:b97d
1272c19:dd:d9:dd:c25:c25:94de:b97e/1282c19:dd:d9:dd:c25:c25:94de:b97e
1282c19:dd:d9:dd:c25:c25:94de:b97f/1282c19:dd:d9:dd:c25:c25:94de:b97f
1292c19:dd:d9:dd:c25:c25:94de:b980/1282c19:dd:d9:dd:c25:c25:94de:b980
1302c19:dd:d9:dd:c25:c25:94de:b981/1282c19:dd:d9:dd:c25:c25:94de:b981
1312c19:dd:d9:dd:c25:c25:94de:b982/1282c19:dd:d9:dd:c25:c25:94de:b982
1322c19:dd:d9:dd:c25:c25:94de:b983/1282c19:dd:d9:dd:c25:c25:94de:b983
1332c19:dd:d9:dd:c25:c25:94de:b984/1282c19:dd:d9:dd:c25:c25:94de:b984
1342c19:dd:d9:dd:c25:c25:94de:b985/1282c19:dd:d9:dd:c25:c25:94de:b985
1352c19:dd:d9:dd:c25:c25:94de:b986/1282c19:dd:d9:dd:c25:c25:94de:b986
1362c19:dd:d9:dd:c25:c25:94de:b987/1282c19:dd:d9:dd:c25:c25:94de:b987
1372c19:dd:d9:dd:c25:c25:94de:b988/1282c19:dd:d9:dd:c25:c25:94de:b988
1382c19:dd:d9:dd:c25:c25:94de:b989/1282c19:dd:d9:dd:c25:c25:94de:b989
1392c19:dd:d9:dd:c25:c25:94de:b98a/1282c19:dd:d9:dd:c25:c25:94de:b98a
1402c19:dd:d9:dd:c25:c25:94de:b98b/1282c19:dd:d9:dd:c25:c25:94de:b98b
1412c19:dd:d9:dd:c25:c25:94de:b98c/1282c19:dd:d9:dd:c25:c25:94de:b98c
1422c19:dd:d9:dd:c25:c25:94de:b98d/1282c19:dd:d9:dd:c25:c25:94de:b98d
1432c19:dd:d9:dd:c25:c25:94de:b98e/1282c19:dd:d9:dd:c25:c25:94de:b98e
1442c19:dd:d9:dd:c25:c25:94de:b98f/1282c19:dd:d9:dd:c25:c25:94de:b98f
1452c19:dd:d9:dd:c25:c25:94de:b990/1282c19:dd:d9:dd:c25:c25:94de:b990
1462c19:dd:d9:dd:c25:c25:94de:b991/1282c19:dd:d9:dd:c25:c25:94de:b991
1472c19:dd:d9:dd:c25:c25:94de:b992/1282c19:dd:d9:dd:c25:c25:94de:b992
1482c19:dd:d9:dd:c25:c25:94de:b993/1282c19:dd:d9:dd:c25:c25:94de:b993
1492c19:dd:d9:dd:c25:c25:94de:b994/1282c19:dd:d9:dd:c25:c25:94de:b994
1502c19:dd:d9:dd:c25:c25:94de:b995/1282c19:dd:d9:dd:c25:c25:94de:b995
1512c19:dd:d9:dd:c25:c25:94de:b996/1282c19:dd:d9:dd:c25:c25:94de:b996
1522c19:dd:d9:dd:c25:c25:94de:b997/1282c19:dd:d9:dd:c25:c25:94de:b997
1532c19:dd:d9:dd:c25:c25:94de:b998/1282c19:dd:d9:dd:c25:c25:94de:b998
1542c19:dd:d9:dd:c25:c25:94de:b999/1282c19:dd:d9:dd:c25:c25:94de:b999
1552c19:dd:d9:dd:c25:c25:94de:b99a/1282c19:dd:d9:dd:c25:c25:94de:b99a
1562c19:dd:d9:dd:c25:c25:94de:b99b/1282c19:dd:d9:dd:c25:c25:94de:b99b
1572c19:dd:d9:dd:c25:c25:94de:b99c/1282c19:dd:d9:dd:c25:c25:94de:b99c
1582c19:dd:d9:dd:c25:c25:94de:b99d/1282c19:dd:d9:dd:c25:c25:94de:b99d
1592c19:dd:d9:dd:c25:c25:94de:b99e/1282c19:dd:d9:dd:c25:c25:94de:b99e
1602c19:dd:d9:dd:c25:c25:94de:b99f/1282c19:dd:d9:dd:c25:c25:94de:b99f
1612c19:dd:d9:dd:c25:c25:94de:b9a0/1282c19:dd:d9:dd:c25:c25:94de:b9a0
1622c19:dd:d9:dd:c25:c25:94de:b9a1/1282c19:dd:d9:dd:c25:c25:94de:b9a1
1632c19:dd:d9:dd:c25:c25:94de:b9a2/1282c19:dd:d9:dd:c25:c25:94de:b9a2
1642c19:dd:d9:dd:c25:c25:94de:b9a3/1282c19:dd:d9:dd:c25:c25:94de:b9a3
1652c19:dd:d9:dd:c25:c25:94de:b9a4/1282c19:dd:d9:dd:c25:c25:94de:b9a4
1662c19:dd:d9:dd:c25:c25:94de:b9a5/1282c19:dd:d9:dd:c25:c25:94de:b9a5
1672c19:dd:d9:dd:c25:c25:94de:b9a6/1282c19:dd:d9:dd:c25:c25:94de:b9a6
1682c19:dd:d9:dd:c25:c25:94de:b9a7/1282c19:dd:d9:dd:c25:c25:94de:b9a7
1692c19:dd:d9:dd:c25:c25:94de:b9a8/1282c19:dd:d9:dd:c25:c25:94de:b9a8
1702c19:dd:d9:dd:c25:c25:94de:b9a9/1282c19:dd:d9:dd:c25:c25:94de:b9a9
1712c19:dd:d9:dd:c25:c25:94de:b9aa/1282c19:dd:d9:dd:c25:c25:94de:b9aa
1722c19:dd:d9:dd:c25:c25:94de:b9ab/1282c19:dd:d9:dd:c25:c25:94de:b9ab
1732c19:dd:d9:dd:c25:c25:94de:b9ac/1282c19:dd:d9:dd:c25:c25:94de:b9ac
1742c19:dd:d9:dd:c25:c25:94de:b9ad/1282c19:dd:d9:dd:c25:c25:94de:b9ad
1752c19:dd:d9:dd:c25:c25:94de:b9ae/1282c19:dd:d9:dd:c25:c25:94de:b9ae
1762c19:dd:d9:dd:c25:c25:94de:b9af/1282c19:dd:d9:dd:c25:c25:94de:b9af
1772c19:dd:d9:dd:c25:c25:94de:b9b0/1282c19:dd:d9:dd:c25:c25:94de:b9b0
1782c19:dd:d9:dd:c25:c25:94de:b9b1/1282c19:dd:d9:dd:c25:c25:94de:b9b1
1792c19:dd:d9:dd:c25:c25:94de:b9b2/1282c19:dd:d9:dd:c25:c25:94de:b9b2
1802c19:dd:d9:dd:c25:c25:94de:b9b3/1282c19:dd:d9:dd:c25:c25:94de:b9b3
1812c19:dd:d9:dd:c25:c25:94de:b9b4/1282c19:dd:d9:dd:c25:c25:94de:b9b4
1822c19:dd:d9:dd:c25:c25:94de:b9b5/1282c19:dd:d9:dd:c25:c25:94de:b9b5
1832c19:dd:d9:dd:c25:c25:94de:b9b6/1282c19:dd:d9:dd:c25:c25:94de:b9b6
1842c19:dd:d9:dd:c25:c25:94de:b9b7/1282c19:dd:d9:dd:c25:c25:94de:b9b7
1852c19:dd:d9:dd:c25:c25:94de:b9b8/1282c19:dd:d9:dd:c25:c25:94de:b9b8
1862c19:dd:d9:dd:c25:c25:94de:b9b9/1282c19:dd:d9:dd:c25:c25:94de:b9b9
1872c19:dd:d9:dd:c25:c25:94de:b9ba/1282c19:dd:d9:dd:c25:c25:94de:b9ba
1882c19:dd:d9:dd:c25:c25:94de:b9bb/1282c19:dd:d9:dd:c25:c25:94de:b9bb
1892c19:dd:d9:dd:c25:c25:94de:b9bc/1282c19:dd:d9:dd:c25:c25:94de:b9bc
1902c19:dd:d9:dd:c25:c25:94de:b9bd/1282c19:dd:d9:dd:c25:c25:94de:b9bd
1912c19:dd:d9:dd:c25:c25:94de:b9be/1282c19:dd:d9:dd:c25:c25:94de:b9be
1922c19:dd:d9:dd:c25:c25:94de:b9bf/1282c19:dd:d9:dd:c25:c25:94de:b9bf
1932c19:dd:d9:dd:c25:c25:94de:b9c0/1282c19:dd:d9:dd:c25:c25:94de:b9c0
1942c19:dd:d9:dd:c25:c25:94de:b9c1/1282c19:dd:d9:dd:c25:c25:94de:b9c1
1952c19:dd:d9:dd:c25:c25:94de:b9c2/1282c19:dd:d9:dd:c25:c25:94de:b9c2
1962c19:dd:d9:dd:c25:c25:94de:b9c3/1282c19:dd:d9:dd:c25:c25:94de:b9c3
1972c19:dd:d9:dd:c25:c25:94de:b9c4/1282c19:dd:d9:dd:c25:c25:94de:b9c4
1982c19:dd:d9:dd:c25:c25:94de:b9c5/1282c19:dd:d9:dd:c25:c25:94de:b9c5
1992c19:dd:d9:dd:c25:c25:94de:b9c6/1282c19:dd:d9:dd:c25:c25:94de:b9c6
2002c19:dd:d9:dd:c25:c25:94de:b9c7/1282c19:dd:d9:dd:c25:c25:94de:b9c7
2012c19:dd:d9:dd:c25:c25:94de:b9c8/1282c19:dd:d9:dd:c25:c25:94de:b9c8
2022c19:dd:d9:dd:c25:c25:94de:b9c9/1282c19:dd:d9:dd:c25:c25:94de:b9c9
2032c19:dd:d9:dd:c25:c25:94de:b9ca/1282c19:dd:d9:dd:c25:c25:94de:b9ca
2042c19:dd:d9:dd:c25:c25:94de:b9cb/1282c19:dd:d9:dd:c25:c25:94de:b9cb
2052c19:dd:d9:dd:c25:c25:94de:b9cc/1282c19:dd:d9:dd:c25:c25:94de:b9cc
2062c19:dd:d9:dd:c25:c25:94de:b9cd/1282c19:dd:d9:dd:c25:c25:94de:b9cd
2072c19:dd:d9:dd:c25:c25:94de:b9ce/1282c19:dd:d9:dd:c25:c25:94de:b9ce
2082c19:dd:d9:dd:c25:c25:94de:b9cf/1282c19:dd:d9:dd:c25:c25:94de:b9cf
2092c19:dd:d9:dd:c25:c25:94de:b9d0/1282c19:dd:d9:dd:c25:c25:94de:b9d0
2102c19:dd:d9:dd:c25:c25:94de:b9d1/1282c19:dd:d9:dd:c25:c25:94de:b9d1
2112c19:dd:d9:dd:c25:c25:94de:b9d2/1282c19:dd:d9:dd:c25:c25:94de:b9d2
2122c19:dd:d9:dd:c25:c25:94de:b9d3/1282c19:dd:d9:dd:c25:c25:94de:b9d3
2132c19:dd:d9:dd:c25:c25:94de:b9d4/1282c19:dd:d9:dd:c25:c25:94de:b9d4
2142c19:dd:d9:dd:c25:c25:94de:b9d5/1282c19:dd:d9:dd:c25:c25:94de:b9d5
2152c19:dd:d9:dd:c25:c25:94de:b9d6/1282c19:dd:d9:dd:c25:c25:94de:b9d6
2162c19:dd:d9:dd:c25:c25:94de:b9d7/1282c19:dd:d9:dd:c25:c25:94de:b9d7
2172c19:dd:d9:dd:c25:c25:94de:b9d8/1282c19:dd:d9:dd:c25:c25:94de:b9d8
2182c19:dd:d9:dd:c25:c25:94de:b9d9/1282c19:dd:d9:dd:c25:c25:94de:b9d9
2192c19:dd:d9:dd:c25:c25:94de:b9da/1282c19:dd:d9:dd:c25:c25:94de:b9da
2202c19:dd:d9:dd:c25:c25:94de:b9db/1282c19:dd:d9:dd:c25:c25:94de:b9db
2212c19:dd:d9:dd:c25:c25:94de:b9dc/1282c19:dd:d9:dd:c25:c25:94de:b9dc
2222c19:dd:d9:dd:c25:c25:94de:b9dd/1282c19:dd:d9:dd:c25:c25:94de:b9dd
2232c19:dd:d9:dd:c25:c25:94de:b9de/1282c19:dd:d9:dd:c25:c25:94de:b9de
2242c19:dd:d9:dd:c25:c25:94de:b9df/1282c19:dd:d9:dd:c25:c25:94de:b9df
2252c19:dd:d9:dd:c25:c25:94de:b9e0/1282c19:dd:d9:dd:c25:c25:94de:b9e0
2262c19:dd:d9:dd:c25:c25:94de:b9e1/1282c19:dd:d9:dd:c25:c25:94de:b9e1
2272c19:dd:d9:dd:c25:c25:94de:b9e2/1282c19:dd:d9:dd:c25:c25:94de:b9e2
2282c19:dd:d9:dd:c25:c25:94de:b9e3/1282c19:dd:d9:dd:c25:c25:94de:b9e3
2292c19:dd:d9:dd:c25:c25:94de:b9e4/1282c19:dd:d9:dd:c25:c25:94de:b9e4
2302c19:dd:d9:dd:c25:c25:94de:b9e5/1282c19:dd:d9:dd:c25:c25:94de:b9e5
2312c19:dd:d9:dd:c25:c25:94de:b9e6/1282c19:dd:d9:dd:c25:c25:94de:b9e6
2322c19:dd:d9:dd:c25:c25:94de:b9e7/1282c19:dd:d9:dd:c25:c25:94de:b9e7
2332c19:dd:d9:dd:c25:c25:94de:b9e8/1282c19:dd:d9:dd:c25:c25:94de:b9e8
2342c19:dd:d9:dd:c25:c25:94de:b9e9/1282c19:dd:d9:dd:c25:c25:94de:b9e9
2352c19:dd:d9:dd:c25:c25:94de:b9ea/1282c19:dd:d9:dd:c25:c25:94de:b9ea
2362c19:dd:d9:dd:c25:c25:94de:b9eb/1282c19:dd:d9:dd:c25:c25:94de:b9eb
2372c19:dd:d9:dd:c25:c25:94de:b9ec/1282c19:dd:d9:dd:c25:c25:94de:b9ec
2382c19:dd:d9:dd:c25:c25:94de:b9ed/1282c19:dd:d9:dd:c25:c25:94de:b9ed
2392c19:dd:d9:dd:c25:c25:94de:b9ee/1282c19:dd:d9:dd:c25:c25:94de:b9ee
2402c19:dd:d9:dd:c25:c25:94de:b9ef/1282c19:dd:d9:dd:c25:c25:94de:b9ef
2412c19:dd:d9:dd:c25:c25:94de:b9f0/1282c19:dd:d9:dd:c25:c25:94de:b9f0
2422c19:dd:d9:dd:c25:c25:94de:b9f1/1282c19:dd:d9:dd:c25:c25:94de:b9f1
2432c19:dd:d9:dd:c25:c25:94de:b9f2/1282c19:dd:d9:dd:c25:c25:94de:b9f2
2442c19:dd:d9:dd:c25:c25:94de:b9f3/1282c19:dd:d9:dd:c25:c25:94de:b9f3
2452c19:dd:d9:dd:c25:c25:94de:b9f4/1282c19:dd:d9:dd:c25:c25:94de:b9f4
2462c19:dd:d9:dd:c25:c25:94de:b9f5/1282c19:dd:d9:dd:c25:c25:94de:b9f5
2472c19:dd:d9:dd:c25:c25:94de:b9f6/1282c19:dd:d9:dd:c25:c25:94de:b9f6
2482c19:dd:d9:dd:c25:c25:94de:b9f7/1282c19:dd:d9:dd:c25:c25:94de:b9f7
2492c19:dd:d9:dd:c25:c25:94de:b9f8/1282c19:dd:d9:dd:c25:c25:94de:b9f8
2502c19:dd:d9:dd:c25:c25:94de:b9f9/1282c19:dd:d9:dd:c25:c25:94de:b9f9
2512c19:dd:d9:dd:c25:c25:94de:b9fa/1282c19:dd:d9:dd:c25:c25:94de:b9fa
2522c19:dd:d9:dd:c25:c25:94de:b9fb/1282c19:dd:d9:dd:c25:c25:94de:b9fb
2532c19:dd:d9:dd:c25:c25:94de:b9fc/1282c19:dd:d9:dd:c25:c25:94de:b9fc
2542c19:dd:d9:dd:c25:c25:94de:b9fd/1282c19:dd:d9:dd:c25:c25:94de:b9fd
2552c19:dd:d9:dd:c25:c25:94de:b9fe/1282c19:dd:d9:dd:c25:c25:94de:b9fe
2562c19:dd:d9:dd:c25:c25:94de:b9ff/1282c19:dd:d9:dd:c25:c25:94de:b9ff

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.