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:ec00:c25:c25e:dd:ddea:da00/120
First address
2c19:dd:ec00:c25:c25e:dd:ddea:da00
Last address
2c19:dd:ec00:c25:c25e:dd:ddea:daff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:ec00:0c25:c25e:00dd:ddea:da00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.d.a.e.d.d.d.d.0.0.e.5.2.c.5.2.c.0.0.0.c.e.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:ec00:c25:c25e:dd:ddea:da00/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:ddea:da00/1282c19:dd:ec00:c25:c25e:dd:ddea:da00
22c19:dd:ec00:c25:c25e:dd:ddea:da01/1282c19:dd:ec00:c25:c25e:dd:ddea:da01
32c19:dd:ec00:c25:c25e:dd:ddea:da02/1282c19:dd:ec00:c25:c25e:dd:ddea:da02
42c19:dd:ec00:c25:c25e:dd:ddea:da03/1282c19:dd:ec00:c25:c25e:dd:ddea:da03
52c19:dd:ec00:c25:c25e:dd:ddea:da04/1282c19:dd:ec00:c25:c25e:dd:ddea:da04
62c19:dd:ec00:c25:c25e:dd:ddea:da05/1282c19:dd:ec00:c25:c25e:dd:ddea:da05
72c19:dd:ec00:c25:c25e:dd:ddea:da06/1282c19:dd:ec00:c25:c25e:dd:ddea:da06
82c19:dd:ec00:c25:c25e:dd:ddea:da07/1282c19:dd:ec00:c25:c25e:dd:ddea:da07
92c19:dd:ec00:c25:c25e:dd:ddea:da08/1282c19:dd:ec00:c25:c25e:dd:ddea:da08
102c19:dd:ec00:c25:c25e:dd:ddea:da09/1282c19:dd:ec00:c25:c25e:dd:ddea:da09
112c19:dd:ec00:c25:c25e:dd:ddea:da0a/1282c19:dd:ec00:c25:c25e:dd:ddea:da0a
122c19:dd:ec00:c25:c25e:dd:ddea:da0b/1282c19:dd:ec00:c25:c25e:dd:ddea:da0b
132c19:dd:ec00:c25:c25e:dd:ddea:da0c/1282c19:dd:ec00:c25:c25e:dd:ddea:da0c
142c19:dd:ec00:c25:c25e:dd:ddea:da0d/1282c19:dd:ec00:c25:c25e:dd:ddea:da0d
152c19:dd:ec00:c25:c25e:dd:ddea:da0e/1282c19:dd:ec00:c25:c25e:dd:ddea:da0e
162c19:dd:ec00:c25:c25e:dd:ddea:da0f/1282c19:dd:ec00:c25:c25e:dd:ddea:da0f
172c19:dd:ec00:c25:c25e:dd:ddea:da10/1282c19:dd:ec00:c25:c25e:dd:ddea:da10
182c19:dd:ec00:c25:c25e:dd:ddea:da11/1282c19:dd:ec00:c25:c25e:dd:ddea:da11
192c19:dd:ec00:c25:c25e:dd:ddea:da12/1282c19:dd:ec00:c25:c25e:dd:ddea:da12
202c19:dd:ec00:c25:c25e:dd:ddea:da13/1282c19:dd:ec00:c25:c25e:dd:ddea:da13
212c19:dd:ec00:c25:c25e:dd:ddea:da14/1282c19:dd:ec00:c25:c25e:dd:ddea:da14
222c19:dd:ec00:c25:c25e:dd:ddea:da15/1282c19:dd:ec00:c25:c25e:dd:ddea:da15
232c19:dd:ec00:c25:c25e:dd:ddea:da16/1282c19:dd:ec00:c25:c25e:dd:ddea:da16
242c19:dd:ec00:c25:c25e:dd:ddea:da17/1282c19:dd:ec00:c25:c25e:dd:ddea:da17
252c19:dd:ec00:c25:c25e:dd:ddea:da18/1282c19:dd:ec00:c25:c25e:dd:ddea:da18
262c19:dd:ec00:c25:c25e:dd:ddea:da19/1282c19:dd:ec00:c25:c25e:dd:ddea:da19
272c19:dd:ec00:c25:c25e:dd:ddea:da1a/1282c19:dd:ec00:c25:c25e:dd:ddea:da1a
282c19:dd:ec00:c25:c25e:dd:ddea:da1b/1282c19:dd:ec00:c25:c25e:dd:ddea:da1b
292c19:dd:ec00:c25:c25e:dd:ddea:da1c/1282c19:dd:ec00:c25:c25e:dd:ddea:da1c
302c19:dd:ec00:c25:c25e:dd:ddea:da1d/1282c19:dd:ec00:c25:c25e:dd:ddea:da1d
312c19:dd:ec00:c25:c25e:dd:ddea:da1e/1282c19:dd:ec00:c25:c25e:dd:ddea:da1e
322c19:dd:ec00:c25:c25e:dd:ddea:da1f/1282c19:dd:ec00:c25:c25e:dd:ddea:da1f
332c19:dd:ec00:c25:c25e:dd:ddea:da20/1282c19:dd:ec00:c25:c25e:dd:ddea:da20
342c19:dd:ec00:c25:c25e:dd:ddea:da21/1282c19:dd:ec00:c25:c25e:dd:ddea:da21
352c19:dd:ec00:c25:c25e:dd:ddea:da22/1282c19:dd:ec00:c25:c25e:dd:ddea:da22
362c19:dd:ec00:c25:c25e:dd:ddea:da23/1282c19:dd:ec00:c25:c25e:dd:ddea:da23
372c19:dd:ec00:c25:c25e:dd:ddea:da24/1282c19:dd:ec00:c25:c25e:dd:ddea:da24
382c19:dd:ec00:c25:c25e:dd:ddea:da25/1282c19:dd:ec00:c25:c25e:dd:ddea:da25
392c19:dd:ec00:c25:c25e:dd:ddea:da26/1282c19:dd:ec00:c25:c25e:dd:ddea:da26
402c19:dd:ec00:c25:c25e:dd:ddea:da27/1282c19:dd:ec00:c25:c25e:dd:ddea:da27
412c19:dd:ec00:c25:c25e:dd:ddea:da28/1282c19:dd:ec00:c25:c25e:dd:ddea:da28
422c19:dd:ec00:c25:c25e:dd:ddea:da29/1282c19:dd:ec00:c25:c25e:dd:ddea:da29
432c19:dd:ec00:c25:c25e:dd:ddea:da2a/1282c19:dd:ec00:c25:c25e:dd:ddea:da2a
442c19:dd:ec00:c25:c25e:dd:ddea:da2b/1282c19:dd:ec00:c25:c25e:dd:ddea:da2b
452c19:dd:ec00:c25:c25e:dd:ddea:da2c/1282c19:dd:ec00:c25:c25e:dd:ddea:da2c
462c19:dd:ec00:c25:c25e:dd:ddea:da2d/1282c19:dd:ec00:c25:c25e:dd:ddea:da2d
472c19:dd:ec00:c25:c25e:dd:ddea:da2e/1282c19:dd:ec00:c25:c25e:dd:ddea:da2e
482c19:dd:ec00:c25:c25e:dd:ddea:da2f/1282c19:dd:ec00:c25:c25e:dd:ddea:da2f
492c19:dd:ec00:c25:c25e:dd:ddea:da30/1282c19:dd:ec00:c25:c25e:dd:ddea:da30
502c19:dd:ec00:c25:c25e:dd:ddea:da31/1282c19:dd:ec00:c25:c25e:dd:ddea:da31
512c19:dd:ec00:c25:c25e:dd:ddea:da32/1282c19:dd:ec00:c25:c25e:dd:ddea:da32
522c19:dd:ec00:c25:c25e:dd:ddea:da33/1282c19:dd:ec00:c25:c25e:dd:ddea:da33
532c19:dd:ec00:c25:c25e:dd:ddea:da34/1282c19:dd:ec00:c25:c25e:dd:ddea:da34
542c19:dd:ec00:c25:c25e:dd:ddea:da35/1282c19:dd:ec00:c25:c25e:dd:ddea:da35
552c19:dd:ec00:c25:c25e:dd:ddea:da36/1282c19:dd:ec00:c25:c25e:dd:ddea:da36
562c19:dd:ec00:c25:c25e:dd:ddea:da37/1282c19:dd:ec00:c25:c25e:dd:ddea:da37
572c19:dd:ec00:c25:c25e:dd:ddea:da38/1282c19:dd:ec00:c25:c25e:dd:ddea:da38
582c19:dd:ec00:c25:c25e:dd:ddea:da39/1282c19:dd:ec00:c25:c25e:dd:ddea:da39
592c19:dd:ec00:c25:c25e:dd:ddea:da3a/1282c19:dd:ec00:c25:c25e:dd:ddea:da3a
602c19:dd:ec00:c25:c25e:dd:ddea:da3b/1282c19:dd:ec00:c25:c25e:dd:ddea:da3b
612c19:dd:ec00:c25:c25e:dd:ddea:da3c/1282c19:dd:ec00:c25:c25e:dd:ddea:da3c
622c19:dd:ec00:c25:c25e:dd:ddea:da3d/1282c19:dd:ec00:c25:c25e:dd:ddea:da3d
632c19:dd:ec00:c25:c25e:dd:ddea:da3e/1282c19:dd:ec00:c25:c25e:dd:ddea:da3e
642c19:dd:ec00:c25:c25e:dd:ddea:da3f/1282c19:dd:ec00:c25:c25e:dd:ddea:da3f
652c19:dd:ec00:c25:c25e:dd:ddea:da40/1282c19:dd:ec00:c25:c25e:dd:ddea:da40
662c19:dd:ec00:c25:c25e:dd:ddea:da41/1282c19:dd:ec00:c25:c25e:dd:ddea:da41
672c19:dd:ec00:c25:c25e:dd:ddea:da42/1282c19:dd:ec00:c25:c25e:dd:ddea:da42
682c19:dd:ec00:c25:c25e:dd:ddea:da43/1282c19:dd:ec00:c25:c25e:dd:ddea:da43
692c19:dd:ec00:c25:c25e:dd:ddea:da44/1282c19:dd:ec00:c25:c25e:dd:ddea:da44
702c19:dd:ec00:c25:c25e:dd:ddea:da45/1282c19:dd:ec00:c25:c25e:dd:ddea:da45
712c19:dd:ec00:c25:c25e:dd:ddea:da46/1282c19:dd:ec00:c25:c25e:dd:ddea:da46
722c19:dd:ec00:c25:c25e:dd:ddea:da47/1282c19:dd:ec00:c25:c25e:dd:ddea:da47
732c19:dd:ec00:c25:c25e:dd:ddea:da48/1282c19:dd:ec00:c25:c25e:dd:ddea:da48
742c19:dd:ec00:c25:c25e:dd:ddea:da49/1282c19:dd:ec00:c25:c25e:dd:ddea:da49
752c19:dd:ec00:c25:c25e:dd:ddea:da4a/1282c19:dd:ec00:c25:c25e:dd:ddea:da4a
762c19:dd:ec00:c25:c25e:dd:ddea:da4b/1282c19:dd:ec00:c25:c25e:dd:ddea:da4b
772c19:dd:ec00:c25:c25e:dd:ddea:da4c/1282c19:dd:ec00:c25:c25e:dd:ddea:da4c
782c19:dd:ec00:c25:c25e:dd:ddea:da4d/1282c19:dd:ec00:c25:c25e:dd:ddea:da4d
792c19:dd:ec00:c25:c25e:dd:ddea:da4e/1282c19:dd:ec00:c25:c25e:dd:ddea:da4e
802c19:dd:ec00:c25:c25e:dd:ddea:da4f/1282c19:dd:ec00:c25:c25e:dd:ddea:da4f
812c19:dd:ec00:c25:c25e:dd:ddea:da50/1282c19:dd:ec00:c25:c25e:dd:ddea:da50
822c19:dd:ec00:c25:c25e:dd:ddea:da51/1282c19:dd:ec00:c25:c25e:dd:ddea:da51
832c19:dd:ec00:c25:c25e:dd:ddea:da52/1282c19:dd:ec00:c25:c25e:dd:ddea:da52
842c19:dd:ec00:c25:c25e:dd:ddea:da53/1282c19:dd:ec00:c25:c25e:dd:ddea:da53
852c19:dd:ec00:c25:c25e:dd:ddea:da54/1282c19:dd:ec00:c25:c25e:dd:ddea:da54
862c19:dd:ec00:c25:c25e:dd:ddea:da55/1282c19:dd:ec00:c25:c25e:dd:ddea:da55
872c19:dd:ec00:c25:c25e:dd:ddea:da56/1282c19:dd:ec00:c25:c25e:dd:ddea:da56
882c19:dd:ec00:c25:c25e:dd:ddea:da57/1282c19:dd:ec00:c25:c25e:dd:ddea:da57
892c19:dd:ec00:c25:c25e:dd:ddea:da58/1282c19:dd:ec00:c25:c25e:dd:ddea:da58
902c19:dd:ec00:c25:c25e:dd:ddea:da59/1282c19:dd:ec00:c25:c25e:dd:ddea:da59
912c19:dd:ec00:c25:c25e:dd:ddea:da5a/1282c19:dd:ec00:c25:c25e:dd:ddea:da5a
922c19:dd:ec00:c25:c25e:dd:ddea:da5b/1282c19:dd:ec00:c25:c25e:dd:ddea:da5b
932c19:dd:ec00:c25:c25e:dd:ddea:da5c/1282c19:dd:ec00:c25:c25e:dd:ddea:da5c
942c19:dd:ec00:c25:c25e:dd:ddea:da5d/1282c19:dd:ec00:c25:c25e:dd:ddea:da5d
952c19:dd:ec00:c25:c25e:dd:ddea:da5e/1282c19:dd:ec00:c25:c25e:dd:ddea:da5e
962c19:dd:ec00:c25:c25e:dd:ddea:da5f/1282c19:dd:ec00:c25:c25e:dd:ddea:da5f
972c19:dd:ec00:c25:c25e:dd:ddea:da60/1282c19:dd:ec00:c25:c25e:dd:ddea:da60
982c19:dd:ec00:c25:c25e:dd:ddea:da61/1282c19:dd:ec00:c25:c25e:dd:ddea:da61
992c19:dd:ec00:c25:c25e:dd:ddea:da62/1282c19:dd:ec00:c25:c25e:dd:ddea:da62
1002c19:dd:ec00:c25:c25e:dd:ddea:da63/1282c19:dd:ec00:c25:c25e:dd:ddea:da63
1012c19:dd:ec00:c25:c25e:dd:ddea:da64/1282c19:dd:ec00:c25:c25e:dd:ddea:da64
1022c19:dd:ec00:c25:c25e:dd:ddea:da65/1282c19:dd:ec00:c25:c25e:dd:ddea:da65
1032c19:dd:ec00:c25:c25e:dd:ddea:da66/1282c19:dd:ec00:c25:c25e:dd:ddea:da66
1042c19:dd:ec00:c25:c25e:dd:ddea:da67/1282c19:dd:ec00:c25:c25e:dd:ddea:da67
1052c19:dd:ec00:c25:c25e:dd:ddea:da68/1282c19:dd:ec00:c25:c25e:dd:ddea:da68
1062c19:dd:ec00:c25:c25e:dd:ddea:da69/1282c19:dd:ec00:c25:c25e:dd:ddea:da69
1072c19:dd:ec00:c25:c25e:dd:ddea:da6a/1282c19:dd:ec00:c25:c25e:dd:ddea:da6a
1082c19:dd:ec00:c25:c25e:dd:ddea:da6b/1282c19:dd:ec00:c25:c25e:dd:ddea:da6b
1092c19:dd:ec00:c25:c25e:dd:ddea:da6c/1282c19:dd:ec00:c25:c25e:dd:ddea:da6c
1102c19:dd:ec00:c25:c25e:dd:ddea:da6d/1282c19:dd:ec00:c25:c25e:dd:ddea:da6d
1112c19:dd:ec00:c25:c25e:dd:ddea:da6e/1282c19:dd:ec00:c25:c25e:dd:ddea:da6e
1122c19:dd:ec00:c25:c25e:dd:ddea:da6f/1282c19:dd:ec00:c25:c25e:dd:ddea:da6f
1132c19:dd:ec00:c25:c25e:dd:ddea:da70/1282c19:dd:ec00:c25:c25e:dd:ddea:da70
1142c19:dd:ec00:c25:c25e:dd:ddea:da71/1282c19:dd:ec00:c25:c25e:dd:ddea:da71
1152c19:dd:ec00:c25:c25e:dd:ddea:da72/1282c19:dd:ec00:c25:c25e:dd:ddea:da72
1162c19:dd:ec00:c25:c25e:dd:ddea:da73/1282c19:dd:ec00:c25:c25e:dd:ddea:da73
1172c19:dd:ec00:c25:c25e:dd:ddea:da74/1282c19:dd:ec00:c25:c25e:dd:ddea:da74
1182c19:dd:ec00:c25:c25e:dd:ddea:da75/1282c19:dd:ec00:c25:c25e:dd:ddea:da75
1192c19:dd:ec00:c25:c25e:dd:ddea:da76/1282c19:dd:ec00:c25:c25e:dd:ddea:da76
1202c19:dd:ec00:c25:c25e:dd:ddea:da77/1282c19:dd:ec00:c25:c25e:dd:ddea:da77
1212c19:dd:ec00:c25:c25e:dd:ddea:da78/1282c19:dd:ec00:c25:c25e:dd:ddea:da78
1222c19:dd:ec00:c25:c25e:dd:ddea:da79/1282c19:dd:ec00:c25:c25e:dd:ddea:da79
1232c19:dd:ec00:c25:c25e:dd:ddea:da7a/1282c19:dd:ec00:c25:c25e:dd:ddea:da7a
1242c19:dd:ec00:c25:c25e:dd:ddea:da7b/1282c19:dd:ec00:c25:c25e:dd:ddea:da7b
1252c19:dd:ec00:c25:c25e:dd:ddea:da7c/1282c19:dd:ec00:c25:c25e:dd:ddea:da7c
1262c19:dd:ec00:c25:c25e:dd:ddea:da7d/1282c19:dd:ec00:c25:c25e:dd:ddea:da7d
1272c19:dd:ec00:c25:c25e:dd:ddea:da7e/1282c19:dd:ec00:c25:c25e:dd:ddea:da7e
1282c19:dd:ec00:c25:c25e:dd:ddea:da7f/1282c19:dd:ec00:c25:c25e:dd:ddea:da7f
1292c19:dd:ec00:c25:c25e:dd:ddea:da80/1282c19:dd:ec00:c25:c25e:dd:ddea:da80
1302c19:dd:ec00:c25:c25e:dd:ddea:da81/1282c19:dd:ec00:c25:c25e:dd:ddea:da81
1312c19:dd:ec00:c25:c25e:dd:ddea:da82/1282c19:dd:ec00:c25:c25e:dd:ddea:da82
1322c19:dd:ec00:c25:c25e:dd:ddea:da83/1282c19:dd:ec00:c25:c25e:dd:ddea:da83
1332c19:dd:ec00:c25:c25e:dd:ddea:da84/1282c19:dd:ec00:c25:c25e:dd:ddea:da84
1342c19:dd:ec00:c25:c25e:dd:ddea:da85/1282c19:dd:ec00:c25:c25e:dd:ddea:da85
1352c19:dd:ec00:c25:c25e:dd:ddea:da86/1282c19:dd:ec00:c25:c25e:dd:ddea:da86
1362c19:dd:ec00:c25:c25e:dd:ddea:da87/1282c19:dd:ec00:c25:c25e:dd:ddea:da87
1372c19:dd:ec00:c25:c25e:dd:ddea:da88/1282c19:dd:ec00:c25:c25e:dd:ddea:da88
1382c19:dd:ec00:c25:c25e:dd:ddea:da89/1282c19:dd:ec00:c25:c25e:dd:ddea:da89
1392c19:dd:ec00:c25:c25e:dd:ddea:da8a/1282c19:dd:ec00:c25:c25e:dd:ddea:da8a
1402c19:dd:ec00:c25:c25e:dd:ddea:da8b/1282c19:dd:ec00:c25:c25e:dd:ddea:da8b
1412c19:dd:ec00:c25:c25e:dd:ddea:da8c/1282c19:dd:ec00:c25:c25e:dd:ddea:da8c
1422c19:dd:ec00:c25:c25e:dd:ddea:da8d/1282c19:dd:ec00:c25:c25e:dd:ddea:da8d
1432c19:dd:ec00:c25:c25e:dd:ddea:da8e/1282c19:dd:ec00:c25:c25e:dd:ddea:da8e
1442c19:dd:ec00:c25:c25e:dd:ddea:da8f/1282c19:dd:ec00:c25:c25e:dd:ddea:da8f
1452c19:dd:ec00:c25:c25e:dd:ddea:da90/1282c19:dd:ec00:c25:c25e:dd:ddea:da90
1462c19:dd:ec00:c25:c25e:dd:ddea:da91/1282c19:dd:ec00:c25:c25e:dd:ddea:da91
1472c19:dd:ec00:c25:c25e:dd:ddea:da92/1282c19:dd:ec00:c25:c25e:dd:ddea:da92
1482c19:dd:ec00:c25:c25e:dd:ddea:da93/1282c19:dd:ec00:c25:c25e:dd:ddea:da93
1492c19:dd:ec00:c25:c25e:dd:ddea:da94/1282c19:dd:ec00:c25:c25e:dd:ddea:da94
1502c19:dd:ec00:c25:c25e:dd:ddea:da95/1282c19:dd:ec00:c25:c25e:dd:ddea:da95
1512c19:dd:ec00:c25:c25e:dd:ddea:da96/1282c19:dd:ec00:c25:c25e:dd:ddea:da96
1522c19:dd:ec00:c25:c25e:dd:ddea:da97/1282c19:dd:ec00:c25:c25e:dd:ddea:da97
1532c19:dd:ec00:c25:c25e:dd:ddea:da98/1282c19:dd:ec00:c25:c25e:dd:ddea:da98
1542c19:dd:ec00:c25:c25e:dd:ddea:da99/1282c19:dd:ec00:c25:c25e:dd:ddea:da99
1552c19:dd:ec00:c25:c25e:dd:ddea:da9a/1282c19:dd:ec00:c25:c25e:dd:ddea:da9a
1562c19:dd:ec00:c25:c25e:dd:ddea:da9b/1282c19:dd:ec00:c25:c25e:dd:ddea:da9b
1572c19:dd:ec00:c25:c25e:dd:ddea:da9c/1282c19:dd:ec00:c25:c25e:dd:ddea:da9c
1582c19:dd:ec00:c25:c25e:dd:ddea:da9d/1282c19:dd:ec00:c25:c25e:dd:ddea:da9d
1592c19:dd:ec00:c25:c25e:dd:ddea:da9e/1282c19:dd:ec00:c25:c25e:dd:ddea:da9e
1602c19:dd:ec00:c25:c25e:dd:ddea:da9f/1282c19:dd:ec00:c25:c25e:dd:ddea:da9f
1612c19:dd:ec00:c25:c25e:dd:ddea:daa0/1282c19:dd:ec00:c25:c25e:dd:ddea:daa0
1622c19:dd:ec00:c25:c25e:dd:ddea:daa1/1282c19:dd:ec00:c25:c25e:dd:ddea:daa1
1632c19:dd:ec00:c25:c25e:dd:ddea:daa2/1282c19:dd:ec00:c25:c25e:dd:ddea:daa2
1642c19:dd:ec00:c25:c25e:dd:ddea:daa3/1282c19:dd:ec00:c25:c25e:dd:ddea:daa3
1652c19:dd:ec00:c25:c25e:dd:ddea:daa4/1282c19:dd:ec00:c25:c25e:dd:ddea:daa4
1662c19:dd:ec00:c25:c25e:dd:ddea:daa5/1282c19:dd:ec00:c25:c25e:dd:ddea:daa5
1672c19:dd:ec00:c25:c25e:dd:ddea:daa6/1282c19:dd:ec00:c25:c25e:dd:ddea:daa6
1682c19:dd:ec00:c25:c25e:dd:ddea:daa7/1282c19:dd:ec00:c25:c25e:dd:ddea:daa7
1692c19:dd:ec00:c25:c25e:dd:ddea:daa8/1282c19:dd:ec00:c25:c25e:dd:ddea:daa8
1702c19:dd:ec00:c25:c25e:dd:ddea:daa9/1282c19:dd:ec00:c25:c25e:dd:ddea:daa9
1712c19:dd:ec00:c25:c25e:dd:ddea:daaa/1282c19:dd:ec00:c25:c25e:dd:ddea:daaa
1722c19:dd:ec00:c25:c25e:dd:ddea:daab/1282c19:dd:ec00:c25:c25e:dd:ddea:daab
1732c19:dd:ec00:c25:c25e:dd:ddea:daac/1282c19:dd:ec00:c25:c25e:dd:ddea:daac
1742c19:dd:ec00:c25:c25e:dd:ddea:daad/1282c19:dd:ec00:c25:c25e:dd:ddea:daad
1752c19:dd:ec00:c25:c25e:dd:ddea:daae/1282c19:dd:ec00:c25:c25e:dd:ddea:daae
1762c19:dd:ec00:c25:c25e:dd:ddea:daaf/1282c19:dd:ec00:c25:c25e:dd:ddea:daaf
1772c19:dd:ec00:c25:c25e:dd:ddea:dab0/1282c19:dd:ec00:c25:c25e:dd:ddea:dab0
1782c19:dd:ec00:c25:c25e:dd:ddea:dab1/1282c19:dd:ec00:c25:c25e:dd:ddea:dab1
1792c19:dd:ec00:c25:c25e:dd:ddea:dab2/1282c19:dd:ec00:c25:c25e:dd:ddea:dab2
1802c19:dd:ec00:c25:c25e:dd:ddea:dab3/1282c19:dd:ec00:c25:c25e:dd:ddea:dab3
1812c19:dd:ec00:c25:c25e:dd:ddea:dab4/1282c19:dd:ec00:c25:c25e:dd:ddea:dab4
1822c19:dd:ec00:c25:c25e:dd:ddea:dab5/1282c19:dd:ec00:c25:c25e:dd:ddea:dab5
1832c19:dd:ec00:c25:c25e:dd:ddea:dab6/1282c19:dd:ec00:c25:c25e:dd:ddea:dab6
1842c19:dd:ec00:c25:c25e:dd:ddea:dab7/1282c19:dd:ec00:c25:c25e:dd:ddea:dab7
1852c19:dd:ec00:c25:c25e:dd:ddea:dab8/1282c19:dd:ec00:c25:c25e:dd:ddea:dab8
1862c19:dd:ec00:c25:c25e:dd:ddea:dab9/1282c19:dd:ec00:c25:c25e:dd:ddea:dab9
1872c19:dd:ec00:c25:c25e:dd:ddea:daba/1282c19:dd:ec00:c25:c25e:dd:ddea:daba
1882c19:dd:ec00:c25:c25e:dd:ddea:dabb/1282c19:dd:ec00:c25:c25e:dd:ddea:dabb
1892c19:dd:ec00:c25:c25e:dd:ddea:dabc/1282c19:dd:ec00:c25:c25e:dd:ddea:dabc
1902c19:dd:ec00:c25:c25e:dd:ddea:dabd/1282c19:dd:ec00:c25:c25e:dd:ddea:dabd
1912c19:dd:ec00:c25:c25e:dd:ddea:dabe/1282c19:dd:ec00:c25:c25e:dd:ddea:dabe
1922c19:dd:ec00:c25:c25e:dd:ddea:dabf/1282c19:dd:ec00:c25:c25e:dd:ddea:dabf
1932c19:dd:ec00:c25:c25e:dd:ddea:dac0/1282c19:dd:ec00:c25:c25e:dd:ddea:dac0
1942c19:dd:ec00:c25:c25e:dd:ddea:dac1/1282c19:dd:ec00:c25:c25e:dd:ddea:dac1
1952c19:dd:ec00:c25:c25e:dd:ddea:dac2/1282c19:dd:ec00:c25:c25e:dd:ddea:dac2
1962c19:dd:ec00:c25:c25e:dd:ddea:dac3/1282c19:dd:ec00:c25:c25e:dd:ddea:dac3
1972c19:dd:ec00:c25:c25e:dd:ddea:dac4/1282c19:dd:ec00:c25:c25e:dd:ddea:dac4
1982c19:dd:ec00:c25:c25e:dd:ddea:dac5/1282c19:dd:ec00:c25:c25e:dd:ddea:dac5
1992c19:dd:ec00:c25:c25e:dd:ddea:dac6/1282c19:dd:ec00:c25:c25e:dd:ddea:dac6
2002c19:dd:ec00:c25:c25e:dd:ddea:dac7/1282c19:dd:ec00:c25:c25e:dd:ddea:dac7
2012c19:dd:ec00:c25:c25e:dd:ddea:dac8/1282c19:dd:ec00:c25:c25e:dd:ddea:dac8
2022c19:dd:ec00:c25:c25e:dd:ddea:dac9/1282c19:dd:ec00:c25:c25e:dd:ddea:dac9
2032c19:dd:ec00:c25:c25e:dd:ddea:daca/1282c19:dd:ec00:c25:c25e:dd:ddea:daca
2042c19:dd:ec00:c25:c25e:dd:ddea:dacb/1282c19:dd:ec00:c25:c25e:dd:ddea:dacb
2052c19:dd:ec00:c25:c25e:dd:ddea:dacc/1282c19:dd:ec00:c25:c25e:dd:ddea:dacc
2062c19:dd:ec00:c25:c25e:dd:ddea:dacd/1282c19:dd:ec00:c25:c25e:dd:ddea:dacd
2072c19:dd:ec00:c25:c25e:dd:ddea:dace/1282c19:dd:ec00:c25:c25e:dd:ddea:dace
2082c19:dd:ec00:c25:c25e:dd:ddea:dacf/1282c19:dd:ec00:c25:c25e:dd:ddea:dacf
2092c19:dd:ec00:c25:c25e:dd:ddea:dad0/1282c19:dd:ec00:c25:c25e:dd:ddea:dad0
2102c19:dd:ec00:c25:c25e:dd:ddea:dad1/1282c19:dd:ec00:c25:c25e:dd:ddea:dad1
2112c19:dd:ec00:c25:c25e:dd:ddea:dad2/1282c19:dd:ec00:c25:c25e:dd:ddea:dad2
2122c19:dd:ec00:c25:c25e:dd:ddea:dad3/1282c19:dd:ec00:c25:c25e:dd:ddea:dad3
2132c19:dd:ec00:c25:c25e:dd:ddea:dad4/1282c19:dd:ec00:c25:c25e:dd:ddea:dad4
2142c19:dd:ec00:c25:c25e:dd:ddea:dad5/1282c19:dd:ec00:c25:c25e:dd:ddea:dad5
2152c19:dd:ec00:c25:c25e:dd:ddea:dad6/1282c19:dd:ec00:c25:c25e:dd:ddea:dad6
2162c19:dd:ec00:c25:c25e:dd:ddea:dad7/1282c19:dd:ec00:c25:c25e:dd:ddea:dad7
2172c19:dd:ec00:c25:c25e:dd:ddea:dad8/1282c19:dd:ec00:c25:c25e:dd:ddea:dad8
2182c19:dd:ec00:c25:c25e:dd:ddea:dad9/1282c19:dd:ec00:c25:c25e:dd:ddea:dad9
2192c19:dd:ec00:c25:c25e:dd:ddea:dada/1282c19:dd:ec00:c25:c25e:dd:ddea:dada
2202c19:dd:ec00:c25:c25e:dd:ddea:dadb/1282c19:dd:ec00:c25:c25e:dd:ddea:dadb
2212c19:dd:ec00:c25:c25e:dd:ddea:dadc/1282c19:dd:ec00:c25:c25e:dd:ddea:dadc
2222c19:dd:ec00:c25:c25e:dd:ddea:dadd/1282c19:dd:ec00:c25:c25e:dd:ddea:dadd
2232c19:dd:ec00:c25:c25e:dd:ddea:dade/1282c19:dd:ec00:c25:c25e:dd:ddea:dade
2242c19:dd:ec00:c25:c25e:dd:ddea:dadf/1282c19:dd:ec00:c25:c25e:dd:ddea:dadf
2252c19:dd:ec00:c25:c25e:dd:ddea:dae0/1282c19:dd:ec00:c25:c25e:dd:ddea:dae0
2262c19:dd:ec00:c25:c25e:dd:ddea:dae1/1282c19:dd:ec00:c25:c25e:dd:ddea:dae1
2272c19:dd:ec00:c25:c25e:dd:ddea:dae2/1282c19:dd:ec00:c25:c25e:dd:ddea:dae2
2282c19:dd:ec00:c25:c25e:dd:ddea:dae3/1282c19:dd:ec00:c25:c25e:dd:ddea:dae3
2292c19:dd:ec00:c25:c25e:dd:ddea:dae4/1282c19:dd:ec00:c25:c25e:dd:ddea:dae4
2302c19:dd:ec00:c25:c25e:dd:ddea:dae5/1282c19:dd:ec00:c25:c25e:dd:ddea:dae5
2312c19:dd:ec00:c25:c25e:dd:ddea:dae6/1282c19:dd:ec00:c25:c25e:dd:ddea:dae6
2322c19:dd:ec00:c25:c25e:dd:ddea:dae7/1282c19:dd:ec00:c25:c25e:dd:ddea:dae7
2332c19:dd:ec00:c25:c25e:dd:ddea:dae8/1282c19:dd:ec00:c25:c25e:dd:ddea:dae8
2342c19:dd:ec00:c25:c25e:dd:ddea:dae9/1282c19:dd:ec00:c25:c25e:dd:ddea:dae9
2352c19:dd:ec00:c25:c25e:dd:ddea:daea/1282c19:dd:ec00:c25:c25e:dd:ddea:daea
2362c19:dd:ec00:c25:c25e:dd:ddea:daeb/1282c19:dd:ec00:c25:c25e:dd:ddea:daeb
2372c19:dd:ec00:c25:c25e:dd:ddea:daec/1282c19:dd:ec00:c25:c25e:dd:ddea:daec
2382c19:dd:ec00:c25:c25e:dd:ddea:daed/1282c19:dd:ec00:c25:c25e:dd:ddea:daed
2392c19:dd:ec00:c25:c25e:dd:ddea:daee/1282c19:dd:ec00:c25:c25e:dd:ddea:daee
2402c19:dd:ec00:c25:c25e:dd:ddea:daef/1282c19:dd:ec00:c25:c25e:dd:ddea:daef
2412c19:dd:ec00:c25:c25e:dd:ddea:daf0/1282c19:dd:ec00:c25:c25e:dd:ddea:daf0
2422c19:dd:ec00:c25:c25e:dd:ddea:daf1/1282c19:dd:ec00:c25:c25e:dd:ddea:daf1
2432c19:dd:ec00:c25:c25e:dd:ddea:daf2/1282c19:dd:ec00:c25:c25e:dd:ddea:daf2
2442c19:dd:ec00:c25:c25e:dd:ddea:daf3/1282c19:dd:ec00:c25:c25e:dd:ddea:daf3
2452c19:dd:ec00:c25:c25e:dd:ddea:daf4/1282c19:dd:ec00:c25:c25e:dd:ddea:daf4
2462c19:dd:ec00:c25:c25e:dd:ddea:daf5/1282c19:dd:ec00:c25:c25e:dd:ddea:daf5
2472c19:dd:ec00:c25:c25e:dd:ddea:daf6/1282c19:dd:ec00:c25:c25e:dd:ddea:daf6
2482c19:dd:ec00:c25:c25e:dd:ddea:daf7/1282c19:dd:ec00:c25:c25e:dd:ddea:daf7
2492c19:dd:ec00:c25:c25e:dd:ddea:daf8/1282c19:dd:ec00:c25:c25e:dd:ddea:daf8
2502c19:dd:ec00:c25:c25e:dd:ddea:daf9/1282c19:dd:ec00:c25:c25e:dd:ddea:daf9
2512c19:dd:ec00:c25:c25e:dd:ddea:dafa/1282c19:dd:ec00:c25:c25e:dd:ddea:dafa
2522c19:dd:ec00:c25:c25e:dd:ddea:dafb/1282c19:dd:ec00:c25:c25e:dd:ddea:dafb
2532c19:dd:ec00:c25:c25e:dd:ddea:dafc/1282c19:dd:ec00:c25:c25e:dd:ddea:dafc
2542c19:dd:ec00:c25:c25e:dd:ddea:dafd/1282c19:dd:ec00:c25:c25e:dd:ddea:dafd
2552c19:dd:ec00:c25:c25e:dd:ddea:dafe/1282c19:dd:ec00:c25:c25e:dd:ddea:dafe
2562c19:dd:ec00:c25:c25e:dd:ddea:daff/1282c19:dd:ec00:c25:c25e:dd:ddea:daff

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.