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:ddbf:aa00/120
First address
2c19:dd:ec00:c25:c25e:dd:ddbf:aa00
Last address
2c19:dd:ec00:c25:c25e:dd:ddbf:aaff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:ec00:0c25:c25e:00dd:ddbf:aa00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.a.f.b.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:ddbf:aa00/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:ddbf:aa00/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa00
22c19:dd:ec00:c25:c25e:dd:ddbf:aa01/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa01
32c19:dd:ec00:c25:c25e:dd:ddbf:aa02/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa02
42c19:dd:ec00:c25:c25e:dd:ddbf:aa03/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa03
52c19:dd:ec00:c25:c25e:dd:ddbf:aa04/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa04
62c19:dd:ec00:c25:c25e:dd:ddbf:aa05/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa05
72c19:dd:ec00:c25:c25e:dd:ddbf:aa06/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa06
82c19:dd:ec00:c25:c25e:dd:ddbf:aa07/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa07
92c19:dd:ec00:c25:c25e:dd:ddbf:aa08/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa08
102c19:dd:ec00:c25:c25e:dd:ddbf:aa09/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa09
112c19:dd:ec00:c25:c25e:dd:ddbf:aa0a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0a
122c19:dd:ec00:c25:c25e:dd:ddbf:aa0b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0b
132c19:dd:ec00:c25:c25e:dd:ddbf:aa0c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0c
142c19:dd:ec00:c25:c25e:dd:ddbf:aa0d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0d
152c19:dd:ec00:c25:c25e:dd:ddbf:aa0e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0e
162c19:dd:ec00:c25:c25e:dd:ddbf:aa0f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa0f
172c19:dd:ec00:c25:c25e:dd:ddbf:aa10/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa10
182c19:dd:ec00:c25:c25e:dd:ddbf:aa11/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa11
192c19:dd:ec00:c25:c25e:dd:ddbf:aa12/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa12
202c19:dd:ec00:c25:c25e:dd:ddbf:aa13/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa13
212c19:dd:ec00:c25:c25e:dd:ddbf:aa14/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa14
222c19:dd:ec00:c25:c25e:dd:ddbf:aa15/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa15
232c19:dd:ec00:c25:c25e:dd:ddbf:aa16/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa16
242c19:dd:ec00:c25:c25e:dd:ddbf:aa17/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa17
252c19:dd:ec00:c25:c25e:dd:ddbf:aa18/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa18
262c19:dd:ec00:c25:c25e:dd:ddbf:aa19/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa19
272c19:dd:ec00:c25:c25e:dd:ddbf:aa1a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1a
282c19:dd:ec00:c25:c25e:dd:ddbf:aa1b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1b
292c19:dd:ec00:c25:c25e:dd:ddbf:aa1c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1c
302c19:dd:ec00:c25:c25e:dd:ddbf:aa1d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1d
312c19:dd:ec00:c25:c25e:dd:ddbf:aa1e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1e
322c19:dd:ec00:c25:c25e:dd:ddbf:aa1f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa1f
332c19:dd:ec00:c25:c25e:dd:ddbf:aa20/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa20
342c19:dd:ec00:c25:c25e:dd:ddbf:aa21/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa21
352c19:dd:ec00:c25:c25e:dd:ddbf:aa22/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa22
362c19:dd:ec00:c25:c25e:dd:ddbf:aa23/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa23
372c19:dd:ec00:c25:c25e:dd:ddbf:aa24/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa24
382c19:dd:ec00:c25:c25e:dd:ddbf:aa25/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa25
392c19:dd:ec00:c25:c25e:dd:ddbf:aa26/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa26
402c19:dd:ec00:c25:c25e:dd:ddbf:aa27/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa27
412c19:dd:ec00:c25:c25e:dd:ddbf:aa28/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa28
422c19:dd:ec00:c25:c25e:dd:ddbf:aa29/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa29
432c19:dd:ec00:c25:c25e:dd:ddbf:aa2a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2a
442c19:dd:ec00:c25:c25e:dd:ddbf:aa2b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2b
452c19:dd:ec00:c25:c25e:dd:ddbf:aa2c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2c
462c19:dd:ec00:c25:c25e:dd:ddbf:aa2d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2d
472c19:dd:ec00:c25:c25e:dd:ddbf:aa2e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2e
482c19:dd:ec00:c25:c25e:dd:ddbf:aa2f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa2f
492c19:dd:ec00:c25:c25e:dd:ddbf:aa30/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa30
502c19:dd:ec00:c25:c25e:dd:ddbf:aa31/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa31
512c19:dd:ec00:c25:c25e:dd:ddbf:aa32/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa32
522c19:dd:ec00:c25:c25e:dd:ddbf:aa33/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa33
532c19:dd:ec00:c25:c25e:dd:ddbf:aa34/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa34
542c19:dd:ec00:c25:c25e:dd:ddbf:aa35/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa35
552c19:dd:ec00:c25:c25e:dd:ddbf:aa36/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa36
562c19:dd:ec00:c25:c25e:dd:ddbf:aa37/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa37
572c19:dd:ec00:c25:c25e:dd:ddbf:aa38/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa38
582c19:dd:ec00:c25:c25e:dd:ddbf:aa39/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa39
592c19:dd:ec00:c25:c25e:dd:ddbf:aa3a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3a
602c19:dd:ec00:c25:c25e:dd:ddbf:aa3b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3b
612c19:dd:ec00:c25:c25e:dd:ddbf:aa3c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3c
622c19:dd:ec00:c25:c25e:dd:ddbf:aa3d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3d
632c19:dd:ec00:c25:c25e:dd:ddbf:aa3e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3e
642c19:dd:ec00:c25:c25e:dd:ddbf:aa3f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa3f
652c19:dd:ec00:c25:c25e:dd:ddbf:aa40/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa40
662c19:dd:ec00:c25:c25e:dd:ddbf:aa41/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa41
672c19:dd:ec00:c25:c25e:dd:ddbf:aa42/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa42
682c19:dd:ec00:c25:c25e:dd:ddbf:aa43/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa43
692c19:dd:ec00:c25:c25e:dd:ddbf:aa44/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa44
702c19:dd:ec00:c25:c25e:dd:ddbf:aa45/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa45
712c19:dd:ec00:c25:c25e:dd:ddbf:aa46/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa46
722c19:dd:ec00:c25:c25e:dd:ddbf:aa47/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa47
732c19:dd:ec00:c25:c25e:dd:ddbf:aa48/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa48
742c19:dd:ec00:c25:c25e:dd:ddbf:aa49/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa49
752c19:dd:ec00:c25:c25e:dd:ddbf:aa4a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4a
762c19:dd:ec00:c25:c25e:dd:ddbf:aa4b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4b
772c19:dd:ec00:c25:c25e:dd:ddbf:aa4c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4c
782c19:dd:ec00:c25:c25e:dd:ddbf:aa4d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4d
792c19:dd:ec00:c25:c25e:dd:ddbf:aa4e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4e
802c19:dd:ec00:c25:c25e:dd:ddbf:aa4f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa4f
812c19:dd:ec00:c25:c25e:dd:ddbf:aa50/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa50
822c19:dd:ec00:c25:c25e:dd:ddbf:aa51/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa51
832c19:dd:ec00:c25:c25e:dd:ddbf:aa52/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa52
842c19:dd:ec00:c25:c25e:dd:ddbf:aa53/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa53
852c19:dd:ec00:c25:c25e:dd:ddbf:aa54/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa54
862c19:dd:ec00:c25:c25e:dd:ddbf:aa55/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa55
872c19:dd:ec00:c25:c25e:dd:ddbf:aa56/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa56
882c19:dd:ec00:c25:c25e:dd:ddbf:aa57/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa57
892c19:dd:ec00:c25:c25e:dd:ddbf:aa58/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa58
902c19:dd:ec00:c25:c25e:dd:ddbf:aa59/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa59
912c19:dd:ec00:c25:c25e:dd:ddbf:aa5a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5a
922c19:dd:ec00:c25:c25e:dd:ddbf:aa5b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5b
932c19:dd:ec00:c25:c25e:dd:ddbf:aa5c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5c
942c19:dd:ec00:c25:c25e:dd:ddbf:aa5d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5d
952c19:dd:ec00:c25:c25e:dd:ddbf:aa5e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5e
962c19:dd:ec00:c25:c25e:dd:ddbf:aa5f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa5f
972c19:dd:ec00:c25:c25e:dd:ddbf:aa60/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa60
982c19:dd:ec00:c25:c25e:dd:ddbf:aa61/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa61
992c19:dd:ec00:c25:c25e:dd:ddbf:aa62/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa62
1002c19:dd:ec00:c25:c25e:dd:ddbf:aa63/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa63
1012c19:dd:ec00:c25:c25e:dd:ddbf:aa64/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa64
1022c19:dd:ec00:c25:c25e:dd:ddbf:aa65/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa65
1032c19:dd:ec00:c25:c25e:dd:ddbf:aa66/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa66
1042c19:dd:ec00:c25:c25e:dd:ddbf:aa67/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa67
1052c19:dd:ec00:c25:c25e:dd:ddbf:aa68/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa68
1062c19:dd:ec00:c25:c25e:dd:ddbf:aa69/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa69
1072c19:dd:ec00:c25:c25e:dd:ddbf:aa6a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6a
1082c19:dd:ec00:c25:c25e:dd:ddbf:aa6b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6b
1092c19:dd:ec00:c25:c25e:dd:ddbf:aa6c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6c
1102c19:dd:ec00:c25:c25e:dd:ddbf:aa6d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6d
1112c19:dd:ec00:c25:c25e:dd:ddbf:aa6e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6e
1122c19:dd:ec00:c25:c25e:dd:ddbf:aa6f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa6f
1132c19:dd:ec00:c25:c25e:dd:ddbf:aa70/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa70
1142c19:dd:ec00:c25:c25e:dd:ddbf:aa71/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa71
1152c19:dd:ec00:c25:c25e:dd:ddbf:aa72/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa72
1162c19:dd:ec00:c25:c25e:dd:ddbf:aa73/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa73
1172c19:dd:ec00:c25:c25e:dd:ddbf:aa74/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa74
1182c19:dd:ec00:c25:c25e:dd:ddbf:aa75/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa75
1192c19:dd:ec00:c25:c25e:dd:ddbf:aa76/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa76
1202c19:dd:ec00:c25:c25e:dd:ddbf:aa77/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa77
1212c19:dd:ec00:c25:c25e:dd:ddbf:aa78/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa78
1222c19:dd:ec00:c25:c25e:dd:ddbf:aa79/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa79
1232c19:dd:ec00:c25:c25e:dd:ddbf:aa7a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7a
1242c19:dd:ec00:c25:c25e:dd:ddbf:aa7b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7b
1252c19:dd:ec00:c25:c25e:dd:ddbf:aa7c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7c
1262c19:dd:ec00:c25:c25e:dd:ddbf:aa7d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7d
1272c19:dd:ec00:c25:c25e:dd:ddbf:aa7e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7e
1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa7f
1292c19:dd:ec00:c25:c25e:dd:ddbf:aa80/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa80
1302c19:dd:ec00:c25:c25e:dd:ddbf:aa81/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa81
1312c19:dd:ec00:c25:c25e:dd:ddbf:aa82/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa82
1322c19:dd:ec00:c25:c25e:dd:ddbf:aa83/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa83
1332c19:dd:ec00:c25:c25e:dd:ddbf:aa84/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa84
1342c19:dd:ec00:c25:c25e:dd:ddbf:aa85/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa85
1352c19:dd:ec00:c25:c25e:dd:ddbf:aa86/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa86
1362c19:dd:ec00:c25:c25e:dd:ddbf:aa87/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa87
1372c19:dd:ec00:c25:c25e:dd:ddbf:aa88/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa88
1382c19:dd:ec00:c25:c25e:dd:ddbf:aa89/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa89
1392c19:dd:ec00:c25:c25e:dd:ddbf:aa8a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8a
1402c19:dd:ec00:c25:c25e:dd:ddbf:aa8b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8b
1412c19:dd:ec00:c25:c25e:dd:ddbf:aa8c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8c
1422c19:dd:ec00:c25:c25e:dd:ddbf:aa8d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8d
1432c19:dd:ec00:c25:c25e:dd:ddbf:aa8e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8e
1442c19:dd:ec00:c25:c25e:dd:ddbf:aa8f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa8f
1452c19:dd:ec00:c25:c25e:dd:ddbf:aa90/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa90
1462c19:dd:ec00:c25:c25e:dd:ddbf:aa91/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa91
1472c19:dd:ec00:c25:c25e:dd:ddbf:aa92/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa92
1482c19:dd:ec00:c25:c25e:dd:ddbf:aa93/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa93
1492c19:dd:ec00:c25:c25e:dd:ddbf:aa94/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa94
1502c19:dd:ec00:c25:c25e:dd:ddbf:aa95/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa95
1512c19:dd:ec00:c25:c25e:dd:ddbf:aa96/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa96
1522c19:dd:ec00:c25:c25e:dd:ddbf:aa97/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa97
1532c19:dd:ec00:c25:c25e:dd:ddbf:aa98/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa98
1542c19:dd:ec00:c25:c25e:dd:ddbf:aa99/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa99
1552c19:dd:ec00:c25:c25e:dd:ddbf:aa9a/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9a
1562c19:dd:ec00:c25:c25e:dd:ddbf:aa9b/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9b
1572c19:dd:ec00:c25:c25e:dd:ddbf:aa9c/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9c
1582c19:dd:ec00:c25:c25e:dd:ddbf:aa9d/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9d
1592c19:dd:ec00:c25:c25e:dd:ddbf:aa9e/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9e
1602c19:dd:ec00:c25:c25e:dd:ddbf:aa9f/1282c19:dd:ec00:c25:c25e:dd:ddbf:aa9f
1612c19:dd:ec00:c25:c25e:dd:ddbf:aaa0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa0
1622c19:dd:ec00:c25:c25e:dd:ddbf:aaa1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa1
1632c19:dd:ec00:c25:c25e:dd:ddbf:aaa2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa2
1642c19:dd:ec00:c25:c25e:dd:ddbf:aaa3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa3
1652c19:dd:ec00:c25:c25e:dd:ddbf:aaa4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa4
1662c19:dd:ec00:c25:c25e:dd:ddbf:aaa5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa5
1672c19:dd:ec00:c25:c25e:dd:ddbf:aaa6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa6
1682c19:dd:ec00:c25:c25e:dd:ddbf:aaa7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa7
1692c19:dd:ec00:c25:c25e:dd:ddbf:aaa8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa8
1702c19:dd:ec00:c25:c25e:dd:ddbf:aaa9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaa9
1712c19:dd:ec00:c25:c25e:dd:ddbf:aaaa/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaaa
1722c19:dd:ec00:c25:c25e:dd:ddbf:aaab/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaab
1732c19:dd:ec00:c25:c25e:dd:ddbf:aaac/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaac
1742c19:dd:ec00:c25:c25e:dd:ddbf:aaad/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaad
1752c19:dd:ec00:c25:c25e:dd:ddbf:aaae/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaae
1762c19:dd:ec00:c25:c25e:dd:ddbf:aaaf/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaaf
1772c19:dd:ec00:c25:c25e:dd:ddbf:aab0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab0
1782c19:dd:ec00:c25:c25e:dd:ddbf:aab1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab1
1792c19:dd:ec00:c25:c25e:dd:ddbf:aab2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab2
1802c19:dd:ec00:c25:c25e:dd:ddbf:aab3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab3
1812c19:dd:ec00:c25:c25e:dd:ddbf:aab4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab4
1822c19:dd:ec00:c25:c25e:dd:ddbf:aab5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab5
1832c19:dd:ec00:c25:c25e:dd:ddbf:aab6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab6
1842c19:dd:ec00:c25:c25e:dd:ddbf:aab7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab7
1852c19:dd:ec00:c25:c25e:dd:ddbf:aab8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab8
1862c19:dd:ec00:c25:c25e:dd:ddbf:aab9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aab9
1872c19:dd:ec00:c25:c25e:dd:ddbf:aaba/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaba
1882c19:dd:ec00:c25:c25e:dd:ddbf:aabb/1282c19:dd:ec00:c25:c25e:dd:ddbf:aabb
1892c19:dd:ec00:c25:c25e:dd:ddbf:aabc/1282c19:dd:ec00:c25:c25e:dd:ddbf:aabc
1902c19:dd:ec00:c25:c25e:dd:ddbf:aabd/1282c19:dd:ec00:c25:c25e:dd:ddbf:aabd
1912c19:dd:ec00:c25:c25e:dd:ddbf:aabe/1282c19:dd:ec00:c25:c25e:dd:ddbf:aabe
1922c19:dd:ec00:c25:c25e:dd:ddbf:aabf/1282c19:dd:ec00:c25:c25e:dd:ddbf:aabf
1932c19:dd:ec00:c25:c25e:dd:ddbf:aac0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac0
1942c19:dd:ec00:c25:c25e:dd:ddbf:aac1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac1
1952c19:dd:ec00:c25:c25e:dd:ddbf:aac2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac2
1962c19:dd:ec00:c25:c25e:dd:ddbf:aac3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac3
1972c19:dd:ec00:c25:c25e:dd:ddbf:aac4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac4
1982c19:dd:ec00:c25:c25e:dd:ddbf:aac5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac5
1992c19:dd:ec00:c25:c25e:dd:ddbf:aac6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac6
2002c19:dd:ec00:c25:c25e:dd:ddbf:aac7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac7
2012c19:dd:ec00:c25:c25e:dd:ddbf:aac8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac8
2022c19:dd:ec00:c25:c25e:dd:ddbf:aac9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aac9
2032c19:dd:ec00:c25:c25e:dd:ddbf:aaca/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaca
2042c19:dd:ec00:c25:c25e:dd:ddbf:aacb/1282c19:dd:ec00:c25:c25e:dd:ddbf:aacb
2052c19:dd:ec00:c25:c25e:dd:ddbf:aacc/1282c19:dd:ec00:c25:c25e:dd:ddbf:aacc
2062c19:dd:ec00:c25:c25e:dd:ddbf:aacd/1282c19:dd:ec00:c25:c25e:dd:ddbf:aacd
2072c19:dd:ec00:c25:c25e:dd:ddbf:aace/1282c19:dd:ec00:c25:c25e:dd:ddbf:aace
2082c19:dd:ec00:c25:c25e:dd:ddbf:aacf/1282c19:dd:ec00:c25:c25e:dd:ddbf:aacf
2092c19:dd:ec00:c25:c25e:dd:ddbf:aad0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad0
2102c19:dd:ec00:c25:c25e:dd:ddbf:aad1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad1
2112c19:dd:ec00:c25:c25e:dd:ddbf:aad2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad2
2122c19:dd:ec00:c25:c25e:dd:ddbf:aad3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad3
2132c19:dd:ec00:c25:c25e:dd:ddbf:aad4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad4
2142c19:dd:ec00:c25:c25e:dd:ddbf:aad5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad5
2152c19:dd:ec00:c25:c25e:dd:ddbf:aad6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad6
2162c19:dd:ec00:c25:c25e:dd:ddbf:aad7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad7
2172c19:dd:ec00:c25:c25e:dd:ddbf:aad8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad8
2182c19:dd:ec00:c25:c25e:dd:ddbf:aad9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aad9
2192c19:dd:ec00:c25:c25e:dd:ddbf:aada/1282c19:dd:ec00:c25:c25e:dd:ddbf:aada
2202c19:dd:ec00:c25:c25e:dd:ddbf:aadb/1282c19:dd:ec00:c25:c25e:dd:ddbf:aadb
2212c19:dd:ec00:c25:c25e:dd:ddbf:aadc/1282c19:dd:ec00:c25:c25e:dd:ddbf:aadc
2222c19:dd:ec00:c25:c25e:dd:ddbf:aadd/1282c19:dd:ec00:c25:c25e:dd:ddbf:aadd
2232c19:dd:ec00:c25:c25e:dd:ddbf:aade/1282c19:dd:ec00:c25:c25e:dd:ddbf:aade
2242c19:dd:ec00:c25:c25e:dd:ddbf:aadf/1282c19:dd:ec00:c25:c25e:dd:ddbf:aadf
2252c19:dd:ec00:c25:c25e:dd:ddbf:aae0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae0
2262c19:dd:ec00:c25:c25e:dd:ddbf:aae1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae1
2272c19:dd:ec00:c25:c25e:dd:ddbf:aae2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae2
2282c19:dd:ec00:c25:c25e:dd:ddbf:aae3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae3
2292c19:dd:ec00:c25:c25e:dd:ddbf:aae4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae4
2302c19:dd:ec00:c25:c25e:dd:ddbf:aae5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae5
2312c19:dd:ec00:c25:c25e:dd:ddbf:aae6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae6
2322c19:dd:ec00:c25:c25e:dd:ddbf:aae7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae7
2332c19:dd:ec00:c25:c25e:dd:ddbf:aae8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae8
2342c19:dd:ec00:c25:c25e:dd:ddbf:aae9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aae9
2352c19:dd:ec00:c25:c25e:dd:ddbf:aaea/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaea
2362c19:dd:ec00:c25:c25e:dd:ddbf:aaeb/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaeb
2372c19:dd:ec00:c25:c25e:dd:ddbf:aaec/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaec
2382c19:dd:ec00:c25:c25e:dd:ddbf:aaed/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaed
2392c19:dd:ec00:c25:c25e:dd:ddbf:aaee/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaee
2402c19:dd:ec00:c25:c25e:dd:ddbf:aaef/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaef
2412c19:dd:ec00:c25:c25e:dd:ddbf:aaf0/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf0
2422c19:dd:ec00:c25:c25e:dd:ddbf:aaf1/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf1
2432c19:dd:ec00:c25:c25e:dd:ddbf:aaf2/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf2
2442c19:dd:ec00:c25:c25e:dd:ddbf:aaf3/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf3
2452c19:dd:ec00:c25:c25e:dd:ddbf:aaf4/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf4
2462c19:dd:ec00:c25:c25e:dd:ddbf:aaf5/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf5
2472c19:dd:ec00:c25:c25e:dd:ddbf:aaf6/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf6
2482c19:dd:ec00:c25:c25e:dd:ddbf:aaf7/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf7
2492c19:dd:ec00:c25:c25e:dd:ddbf:aaf8/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf8
2502c19:dd:ec00:c25:c25e:dd:ddbf:aaf9/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaf9
2512c19:dd:ec00:c25:c25e:dd:ddbf:aafa/1282c19:dd:ec00:c25:c25e:dd:ddbf:aafa
2522c19:dd:ec00:c25:c25e:dd:ddbf:aafb/1282c19:dd:ec00:c25:c25e:dd:ddbf:aafb
2532c19:dd:ec00:c25:c25e:dd:ddbf:aafc/1282c19:dd:ec00:c25:c25e:dd:ddbf:aafc
2542c19:dd:ec00:c25:c25e:dd:ddbf:aafd/1282c19:dd:ec00:c25:c25e:dd:ddbf:aafd
2552c19:dd:ec00:c25:c25e:dd:ddbf:aafe/1282c19:dd:ec00:c25:c25e:dd:ddbf:aafe
2562c19:dd:ec00:c25:c25e:dd:ddbf:aaff/1282c19:dd:ec00:c25:c25e:dd:ddbf:aaff

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.