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:ddcd:c00/120
First address
2c19:dd:ec00:c25:c25e:dd:ddcd:c00
Last address
2c19:dd:ec00:c25:c25e:dd:ddcd:cff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:ec00:0c25:c25e:00dd:ddcd:0c00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
c.0.d.c.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:ddcd:c00/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:ddcd:c00/1282c19:dd:ec00:c25:c25e:dd:ddcd:c00
22c19:dd:ec00:c25:c25e:dd:ddcd:c01/1282c19:dd:ec00:c25:c25e:dd:ddcd:c01
32c19:dd:ec00:c25:c25e:dd:ddcd:c02/1282c19:dd:ec00:c25:c25e:dd:ddcd:c02
42c19:dd:ec00:c25:c25e:dd:ddcd:c03/1282c19:dd:ec00:c25:c25e:dd:ddcd:c03
52c19:dd:ec00:c25:c25e:dd:ddcd:c04/1282c19:dd:ec00:c25:c25e:dd:ddcd:c04
62c19:dd:ec00:c25:c25e:dd:ddcd:c05/1282c19:dd:ec00:c25:c25e:dd:ddcd:c05
72c19:dd:ec00:c25:c25e:dd:ddcd:c06/1282c19:dd:ec00:c25:c25e:dd:ddcd:c06
82c19:dd:ec00:c25:c25e:dd:ddcd:c07/1282c19:dd:ec00:c25:c25e:dd:ddcd:c07
92c19:dd:ec00:c25:c25e:dd:ddcd:c08/1282c19:dd:ec00:c25:c25e:dd:ddcd:c08
102c19:dd:ec00:c25:c25e:dd:ddcd:c09/1282c19:dd:ec00:c25:c25e:dd:ddcd:c09
112c19:dd:ec00:c25:c25e:dd:ddcd:c0a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0a
122c19:dd:ec00:c25:c25e:dd:ddcd:c0b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0b
132c19:dd:ec00:c25:c25e:dd:ddcd:c0c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0c
142c19:dd:ec00:c25:c25e:dd:ddcd:c0d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0d
152c19:dd:ec00:c25:c25e:dd:ddcd:c0e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0e
162c19:dd:ec00:c25:c25e:dd:ddcd:c0f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c0f
172c19:dd:ec00:c25:c25e:dd:ddcd:c10/1282c19:dd:ec00:c25:c25e:dd:ddcd:c10
182c19:dd:ec00:c25:c25e:dd:ddcd:c11/1282c19:dd:ec00:c25:c25e:dd:ddcd:c11
192c19:dd:ec00:c25:c25e:dd:ddcd:c12/1282c19:dd:ec00:c25:c25e:dd:ddcd:c12
202c19:dd:ec00:c25:c25e:dd:ddcd:c13/1282c19:dd:ec00:c25:c25e:dd:ddcd:c13
212c19:dd:ec00:c25:c25e:dd:ddcd:c14/1282c19:dd:ec00:c25:c25e:dd:ddcd:c14
222c19:dd:ec00:c25:c25e:dd:ddcd:c15/1282c19:dd:ec00:c25:c25e:dd:ddcd:c15
232c19:dd:ec00:c25:c25e:dd:ddcd:c16/1282c19:dd:ec00:c25:c25e:dd:ddcd:c16
242c19:dd:ec00:c25:c25e:dd:ddcd:c17/1282c19:dd:ec00:c25:c25e:dd:ddcd:c17
252c19:dd:ec00:c25:c25e:dd:ddcd:c18/1282c19:dd:ec00:c25:c25e:dd:ddcd:c18
262c19:dd:ec00:c25:c25e:dd:ddcd:c19/1282c19:dd:ec00:c25:c25e:dd:ddcd:c19
272c19:dd:ec00:c25:c25e:dd:ddcd:c1a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1a
282c19:dd:ec00:c25:c25e:dd:ddcd:c1b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1b
292c19:dd:ec00:c25:c25e:dd:ddcd:c1c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1c
302c19:dd:ec00:c25:c25e:dd:ddcd:c1d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1d
312c19:dd:ec00:c25:c25e:dd:ddcd:c1e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1e
322c19:dd:ec00:c25:c25e:dd:ddcd:c1f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c1f
332c19:dd:ec00:c25:c25e:dd:ddcd:c20/1282c19:dd:ec00:c25:c25e:dd:ddcd:c20
342c19:dd:ec00:c25:c25e:dd:ddcd:c21/1282c19:dd:ec00:c25:c25e:dd:ddcd:c21
352c19:dd:ec00:c25:c25e:dd:ddcd:c22/1282c19:dd:ec00:c25:c25e:dd:ddcd:c22
362c19:dd:ec00:c25:c25e:dd:ddcd:c23/1282c19:dd:ec00:c25:c25e:dd:ddcd:c23
372c19:dd:ec00:c25:c25e:dd:ddcd:c24/1282c19:dd:ec00:c25:c25e:dd:ddcd:c24
382c19:dd:ec00:c25:c25e:dd:ddcd:c25/1282c19:dd:ec00:c25:c25e:dd:ddcd:c25
392c19:dd:ec00:c25:c25e:dd:ddcd:c26/1282c19:dd:ec00:c25:c25e:dd:ddcd:c26
402c19:dd:ec00:c25:c25e:dd:ddcd:c27/1282c19:dd:ec00:c25:c25e:dd:ddcd:c27
412c19:dd:ec00:c25:c25e:dd:ddcd:c28/1282c19:dd:ec00:c25:c25e:dd:ddcd:c28
422c19:dd:ec00:c25:c25e:dd:ddcd:c29/1282c19:dd:ec00:c25:c25e:dd:ddcd:c29
432c19:dd:ec00:c25:c25e:dd:ddcd:c2a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2a
442c19:dd:ec00:c25:c25e:dd:ddcd:c2b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2b
452c19:dd:ec00:c25:c25e:dd:ddcd:c2c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2c
462c19:dd:ec00:c25:c25e:dd:ddcd:c2d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2d
472c19:dd:ec00:c25:c25e:dd:ddcd:c2e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2e
482c19:dd:ec00:c25:c25e:dd:ddcd:c2f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c2f
492c19:dd:ec00:c25:c25e:dd:ddcd:c30/1282c19:dd:ec00:c25:c25e:dd:ddcd:c30
502c19:dd:ec00:c25:c25e:dd:ddcd:c31/1282c19:dd:ec00:c25:c25e:dd:ddcd:c31
512c19:dd:ec00:c25:c25e:dd:ddcd:c32/1282c19:dd:ec00:c25:c25e:dd:ddcd:c32
522c19:dd:ec00:c25:c25e:dd:ddcd:c33/1282c19:dd:ec00:c25:c25e:dd:ddcd:c33
532c19:dd:ec00:c25:c25e:dd:ddcd:c34/1282c19:dd:ec00:c25:c25e:dd:ddcd:c34
542c19:dd:ec00:c25:c25e:dd:ddcd:c35/1282c19:dd:ec00:c25:c25e:dd:ddcd:c35
552c19:dd:ec00:c25:c25e:dd:ddcd:c36/1282c19:dd:ec00:c25:c25e:dd:ddcd:c36
562c19:dd:ec00:c25:c25e:dd:ddcd:c37/1282c19:dd:ec00:c25:c25e:dd:ddcd:c37
572c19:dd:ec00:c25:c25e:dd:ddcd:c38/1282c19:dd:ec00:c25:c25e:dd:ddcd:c38
582c19:dd:ec00:c25:c25e:dd:ddcd:c39/1282c19:dd:ec00:c25:c25e:dd:ddcd:c39
592c19:dd:ec00:c25:c25e:dd:ddcd:c3a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3a
602c19:dd:ec00:c25:c25e:dd:ddcd:c3b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3b
612c19:dd:ec00:c25:c25e:dd:ddcd:c3c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3c
622c19:dd:ec00:c25:c25e:dd:ddcd:c3d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3d
632c19:dd:ec00:c25:c25e:dd:ddcd:c3e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3e
642c19:dd:ec00:c25:c25e:dd:ddcd:c3f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c3f
652c19:dd:ec00:c25:c25e:dd:ddcd:c40/1282c19:dd:ec00:c25:c25e:dd:ddcd:c40
662c19:dd:ec00:c25:c25e:dd:ddcd:c41/1282c19:dd:ec00:c25:c25e:dd:ddcd:c41
672c19:dd:ec00:c25:c25e:dd:ddcd:c42/1282c19:dd:ec00:c25:c25e:dd:ddcd:c42
682c19:dd:ec00:c25:c25e:dd:ddcd:c43/1282c19:dd:ec00:c25:c25e:dd:ddcd:c43
692c19:dd:ec00:c25:c25e:dd:ddcd:c44/1282c19:dd:ec00:c25:c25e:dd:ddcd:c44
702c19:dd:ec00:c25:c25e:dd:ddcd:c45/1282c19:dd:ec00:c25:c25e:dd:ddcd:c45
712c19:dd:ec00:c25:c25e:dd:ddcd:c46/1282c19:dd:ec00:c25:c25e:dd:ddcd:c46
722c19:dd:ec00:c25:c25e:dd:ddcd:c47/1282c19:dd:ec00:c25:c25e:dd:ddcd:c47
732c19:dd:ec00:c25:c25e:dd:ddcd:c48/1282c19:dd:ec00:c25:c25e:dd:ddcd:c48
742c19:dd:ec00:c25:c25e:dd:ddcd:c49/1282c19:dd:ec00:c25:c25e:dd:ddcd:c49
752c19:dd:ec00:c25:c25e:dd:ddcd:c4a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4a
762c19:dd:ec00:c25:c25e:dd:ddcd:c4b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4b
772c19:dd:ec00:c25:c25e:dd:ddcd:c4c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4c
782c19:dd:ec00:c25:c25e:dd:ddcd:c4d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4d
792c19:dd:ec00:c25:c25e:dd:ddcd:c4e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4e
802c19:dd:ec00:c25:c25e:dd:ddcd:c4f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c4f
812c19:dd:ec00:c25:c25e:dd:ddcd:c50/1282c19:dd:ec00:c25:c25e:dd:ddcd:c50
822c19:dd:ec00:c25:c25e:dd:ddcd:c51/1282c19:dd:ec00:c25:c25e:dd:ddcd:c51
832c19:dd:ec00:c25:c25e:dd:ddcd:c52/1282c19:dd:ec00:c25:c25e:dd:ddcd:c52
842c19:dd:ec00:c25:c25e:dd:ddcd:c53/1282c19:dd:ec00:c25:c25e:dd:ddcd:c53
852c19:dd:ec00:c25:c25e:dd:ddcd:c54/1282c19:dd:ec00:c25:c25e:dd:ddcd:c54
862c19:dd:ec00:c25:c25e:dd:ddcd:c55/1282c19:dd:ec00:c25:c25e:dd:ddcd:c55
872c19:dd:ec00:c25:c25e:dd:ddcd:c56/1282c19:dd:ec00:c25:c25e:dd:ddcd:c56
882c19:dd:ec00:c25:c25e:dd:ddcd:c57/1282c19:dd:ec00:c25:c25e:dd:ddcd:c57
892c19:dd:ec00:c25:c25e:dd:ddcd:c58/1282c19:dd:ec00:c25:c25e:dd:ddcd:c58
902c19:dd:ec00:c25:c25e:dd:ddcd:c59/1282c19:dd:ec00:c25:c25e:dd:ddcd:c59
912c19:dd:ec00:c25:c25e:dd:ddcd:c5a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5a
922c19:dd:ec00:c25:c25e:dd:ddcd:c5b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5b
932c19:dd:ec00:c25:c25e:dd:ddcd:c5c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5c
942c19:dd:ec00:c25:c25e:dd:ddcd:c5d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5d
952c19:dd:ec00:c25:c25e:dd:ddcd:c5e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5e
962c19:dd:ec00:c25:c25e:dd:ddcd:c5f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c5f
972c19:dd:ec00:c25:c25e:dd:ddcd:c60/1282c19:dd:ec00:c25:c25e:dd:ddcd:c60
982c19:dd:ec00:c25:c25e:dd:ddcd:c61/1282c19:dd:ec00:c25:c25e:dd:ddcd:c61
992c19:dd:ec00:c25:c25e:dd:ddcd:c62/1282c19:dd:ec00:c25:c25e:dd:ddcd:c62
1002c19:dd:ec00:c25:c25e:dd:ddcd:c63/1282c19:dd:ec00:c25:c25e:dd:ddcd:c63
1012c19:dd:ec00:c25:c25e:dd:ddcd:c64/1282c19:dd:ec00:c25:c25e:dd:ddcd:c64
1022c19:dd:ec00:c25:c25e:dd:ddcd:c65/1282c19:dd:ec00:c25:c25e:dd:ddcd:c65
1032c19:dd:ec00:c25:c25e:dd:ddcd:c66/1282c19:dd:ec00:c25:c25e:dd:ddcd:c66
1042c19:dd:ec00:c25:c25e:dd:ddcd:c67/1282c19:dd:ec00:c25:c25e:dd:ddcd:c67
1052c19:dd:ec00:c25:c25e:dd:ddcd:c68/1282c19:dd:ec00:c25:c25e:dd:ddcd:c68
1062c19:dd:ec00:c25:c25e:dd:ddcd:c69/1282c19:dd:ec00:c25:c25e:dd:ddcd:c69
1072c19:dd:ec00:c25:c25e:dd:ddcd:c6a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6a
1082c19:dd:ec00:c25:c25e:dd:ddcd:c6b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6b
1092c19:dd:ec00:c25:c25e:dd:ddcd:c6c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6c
1102c19:dd:ec00:c25:c25e:dd:ddcd:c6d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6d
1112c19:dd:ec00:c25:c25e:dd:ddcd:c6e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6e
1122c19:dd:ec00:c25:c25e:dd:ddcd:c6f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c6f
1132c19:dd:ec00:c25:c25e:dd:ddcd:c70/1282c19:dd:ec00:c25:c25e:dd:ddcd:c70
1142c19:dd:ec00:c25:c25e:dd:ddcd:c71/1282c19:dd:ec00:c25:c25e:dd:ddcd:c71
1152c19:dd:ec00:c25:c25e:dd:ddcd:c72/1282c19:dd:ec00:c25:c25e:dd:ddcd:c72
1162c19:dd:ec00:c25:c25e:dd:ddcd:c73/1282c19:dd:ec00:c25:c25e:dd:ddcd:c73
1172c19:dd:ec00:c25:c25e:dd:ddcd:c74/1282c19:dd:ec00:c25:c25e:dd:ddcd:c74
1182c19:dd:ec00:c25:c25e:dd:ddcd:c75/1282c19:dd:ec00:c25:c25e:dd:ddcd:c75
1192c19:dd:ec00:c25:c25e:dd:ddcd:c76/1282c19:dd:ec00:c25:c25e:dd:ddcd:c76
1202c19:dd:ec00:c25:c25e:dd:ddcd:c77/1282c19:dd:ec00:c25:c25e:dd:ddcd:c77
1212c19:dd:ec00:c25:c25e:dd:ddcd:c78/1282c19:dd:ec00:c25:c25e:dd:ddcd:c78
1222c19:dd:ec00:c25:c25e:dd:ddcd:c79/1282c19:dd:ec00:c25:c25e:dd:ddcd:c79
1232c19:dd:ec00:c25:c25e:dd:ddcd:c7a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7a
1242c19:dd:ec00:c25:c25e:dd:ddcd:c7b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7b
1252c19:dd:ec00:c25:c25e:dd:ddcd:c7c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7c
1262c19:dd:ec00:c25:c25e:dd:ddcd:c7d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7d
1272c19:dd:ec00:c25:c25e:dd:ddcd:c7e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7e
1282c19:dd:ec00:c25:c25e:dd:ddcd:c7f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c7f
1292c19:dd:ec00:c25:c25e:dd:ddcd:c80/1282c19:dd:ec00:c25:c25e:dd:ddcd:c80
1302c19:dd:ec00:c25:c25e:dd:ddcd:c81/1282c19:dd:ec00:c25:c25e:dd:ddcd:c81
1312c19:dd:ec00:c25:c25e:dd:ddcd:c82/1282c19:dd:ec00:c25:c25e:dd:ddcd:c82
1322c19:dd:ec00:c25:c25e:dd:ddcd:c83/1282c19:dd:ec00:c25:c25e:dd:ddcd:c83
1332c19:dd:ec00:c25:c25e:dd:ddcd:c84/1282c19:dd:ec00:c25:c25e:dd:ddcd:c84
1342c19:dd:ec00:c25:c25e:dd:ddcd:c85/1282c19:dd:ec00:c25:c25e:dd:ddcd:c85
1352c19:dd:ec00:c25:c25e:dd:ddcd:c86/1282c19:dd:ec00:c25:c25e:dd:ddcd:c86
1362c19:dd:ec00:c25:c25e:dd:ddcd:c87/1282c19:dd:ec00:c25:c25e:dd:ddcd:c87
1372c19:dd:ec00:c25:c25e:dd:ddcd:c88/1282c19:dd:ec00:c25:c25e:dd:ddcd:c88
1382c19:dd:ec00:c25:c25e:dd:ddcd:c89/1282c19:dd:ec00:c25:c25e:dd:ddcd:c89
1392c19:dd:ec00:c25:c25e:dd:ddcd:c8a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8a
1402c19:dd:ec00:c25:c25e:dd:ddcd:c8b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8b
1412c19:dd:ec00:c25:c25e:dd:ddcd:c8c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8c
1422c19:dd:ec00:c25:c25e:dd:ddcd:c8d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8d
1432c19:dd:ec00:c25:c25e:dd:ddcd:c8e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8e
1442c19:dd:ec00:c25:c25e:dd:ddcd:c8f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c8f
1452c19:dd:ec00:c25:c25e:dd:ddcd:c90/1282c19:dd:ec00:c25:c25e:dd:ddcd:c90
1462c19:dd:ec00:c25:c25e:dd:ddcd:c91/1282c19:dd:ec00:c25:c25e:dd:ddcd:c91
1472c19:dd:ec00:c25:c25e:dd:ddcd:c92/1282c19:dd:ec00:c25:c25e:dd:ddcd:c92
1482c19:dd:ec00:c25:c25e:dd:ddcd:c93/1282c19:dd:ec00:c25:c25e:dd:ddcd:c93
1492c19:dd:ec00:c25:c25e:dd:ddcd:c94/1282c19:dd:ec00:c25:c25e:dd:ddcd:c94
1502c19:dd:ec00:c25:c25e:dd:ddcd:c95/1282c19:dd:ec00:c25:c25e:dd:ddcd:c95
1512c19:dd:ec00:c25:c25e:dd:ddcd:c96/1282c19:dd:ec00:c25:c25e:dd:ddcd:c96
1522c19:dd:ec00:c25:c25e:dd:ddcd:c97/1282c19:dd:ec00:c25:c25e:dd:ddcd:c97
1532c19:dd:ec00:c25:c25e:dd:ddcd:c98/1282c19:dd:ec00:c25:c25e:dd:ddcd:c98
1542c19:dd:ec00:c25:c25e:dd:ddcd:c99/1282c19:dd:ec00:c25:c25e:dd:ddcd:c99
1552c19:dd:ec00:c25:c25e:dd:ddcd:c9a/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9a
1562c19:dd:ec00:c25:c25e:dd:ddcd:c9b/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9b
1572c19:dd:ec00:c25:c25e:dd:ddcd:c9c/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9c
1582c19:dd:ec00:c25:c25e:dd:ddcd:c9d/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9d
1592c19:dd:ec00:c25:c25e:dd:ddcd:c9e/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9e
1602c19:dd:ec00:c25:c25e:dd:ddcd:c9f/1282c19:dd:ec00:c25:c25e:dd:ddcd:c9f
1612c19:dd:ec00:c25:c25e:dd:ddcd:ca0/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca0
1622c19:dd:ec00:c25:c25e:dd:ddcd:ca1/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca1
1632c19:dd:ec00:c25:c25e:dd:ddcd:ca2/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca2
1642c19:dd:ec00:c25:c25e:dd:ddcd:ca3/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca3
1652c19:dd:ec00:c25:c25e:dd:ddcd:ca4/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca4
1662c19:dd:ec00:c25:c25e:dd:ddcd:ca5/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca5
1672c19:dd:ec00:c25:c25e:dd:ddcd:ca6/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca6
1682c19:dd:ec00:c25:c25e:dd:ddcd:ca7/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca7
1692c19:dd:ec00:c25:c25e:dd:ddcd:ca8/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca8
1702c19:dd:ec00:c25:c25e:dd:ddcd:ca9/1282c19:dd:ec00:c25:c25e:dd:ddcd:ca9
1712c19:dd:ec00:c25:c25e:dd:ddcd:caa/1282c19:dd:ec00:c25:c25e:dd:ddcd:caa
1722c19:dd:ec00:c25:c25e:dd:ddcd:cab/1282c19:dd:ec00:c25:c25e:dd:ddcd:cab
1732c19:dd:ec00:c25:c25e:dd:ddcd:cac/1282c19:dd:ec00:c25:c25e:dd:ddcd:cac
1742c19:dd:ec00:c25:c25e:dd:ddcd:cad/1282c19:dd:ec00:c25:c25e:dd:ddcd:cad
1752c19:dd:ec00:c25:c25e:dd:ddcd:cae/1282c19:dd:ec00:c25:c25e:dd:ddcd:cae
1762c19:dd:ec00:c25:c25e:dd:ddcd:caf/1282c19:dd:ec00:c25:c25e:dd:ddcd:caf
1772c19:dd:ec00:c25:c25e:dd:ddcd:cb0/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb0
1782c19:dd:ec00:c25:c25e:dd:ddcd:cb1/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb1
1792c19:dd:ec00:c25:c25e:dd:ddcd:cb2/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb2
1802c19:dd:ec00:c25:c25e:dd:ddcd:cb3/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb3
1812c19:dd:ec00:c25:c25e:dd:ddcd:cb4/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb4
1822c19:dd:ec00:c25:c25e:dd:ddcd:cb5/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb5
1832c19:dd:ec00:c25:c25e:dd:ddcd:cb6/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb6
1842c19:dd:ec00:c25:c25e:dd:ddcd:cb7/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb7
1852c19:dd:ec00:c25:c25e:dd:ddcd:cb8/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb8
1862c19:dd:ec00:c25:c25e:dd:ddcd:cb9/1282c19:dd:ec00:c25:c25e:dd:ddcd:cb9
1872c19:dd:ec00:c25:c25e:dd:ddcd:cba/1282c19:dd:ec00:c25:c25e:dd:ddcd:cba
1882c19:dd:ec00:c25:c25e:dd:ddcd:cbb/1282c19:dd:ec00:c25:c25e:dd:ddcd:cbb
1892c19:dd:ec00:c25:c25e:dd:ddcd:cbc/1282c19:dd:ec00:c25:c25e:dd:ddcd:cbc
1902c19:dd:ec00:c25:c25e:dd:ddcd:cbd/1282c19:dd:ec00:c25:c25e:dd:ddcd:cbd
1912c19:dd:ec00:c25:c25e:dd:ddcd:cbe/1282c19:dd:ec00:c25:c25e:dd:ddcd:cbe
1922c19:dd:ec00:c25:c25e:dd:ddcd:cbf/1282c19:dd:ec00:c25:c25e:dd:ddcd:cbf
1932c19:dd:ec00:c25:c25e:dd:ddcd:cc0/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc0
1942c19:dd:ec00:c25:c25e:dd:ddcd:cc1/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc1
1952c19:dd:ec00:c25:c25e:dd:ddcd:cc2/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc2
1962c19:dd:ec00:c25:c25e:dd:ddcd:cc3/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc3
1972c19:dd:ec00:c25:c25e:dd:ddcd:cc4/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc4
1982c19:dd:ec00:c25:c25e:dd:ddcd:cc5/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc5
1992c19:dd:ec00:c25:c25e:dd:ddcd:cc6/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc6
2002c19:dd:ec00:c25:c25e:dd:ddcd:cc7/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc7
2012c19:dd:ec00:c25:c25e:dd:ddcd:cc8/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc8
2022c19:dd:ec00:c25:c25e:dd:ddcd:cc9/1282c19:dd:ec00:c25:c25e:dd:ddcd:cc9
2032c19:dd:ec00:c25:c25e:dd:ddcd:cca/1282c19:dd:ec00:c25:c25e:dd:ddcd:cca
2042c19:dd:ec00:c25:c25e:dd:ddcd:ccb/1282c19:dd:ec00:c25:c25e:dd:ddcd:ccb
2052c19:dd:ec00:c25:c25e:dd:ddcd:ccc/1282c19:dd:ec00:c25:c25e:dd:ddcd:ccc
2062c19:dd:ec00:c25:c25e:dd:ddcd:ccd/1282c19:dd:ec00:c25:c25e:dd:ddcd:ccd
2072c19:dd:ec00:c25:c25e:dd:ddcd:cce/1282c19:dd:ec00:c25:c25e:dd:ddcd:cce
2082c19:dd:ec00:c25:c25e:dd:ddcd:ccf/1282c19:dd:ec00:c25:c25e:dd:ddcd:ccf
2092c19:dd:ec00:c25:c25e:dd:ddcd:cd0/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd0
2102c19:dd:ec00:c25:c25e:dd:ddcd:cd1/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd1
2112c19:dd:ec00:c25:c25e:dd:ddcd:cd2/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd2
2122c19:dd:ec00:c25:c25e:dd:ddcd:cd3/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd3
2132c19:dd:ec00:c25:c25e:dd:ddcd:cd4/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd4
2142c19:dd:ec00:c25:c25e:dd:ddcd:cd5/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd5
2152c19:dd:ec00:c25:c25e:dd:ddcd:cd6/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd6
2162c19:dd:ec00:c25:c25e:dd:ddcd:cd7/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd7
2172c19:dd:ec00:c25:c25e:dd:ddcd:cd8/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd8
2182c19:dd:ec00:c25:c25e:dd:ddcd:cd9/1282c19:dd:ec00:c25:c25e:dd:ddcd:cd9
2192c19:dd:ec00:c25:c25e:dd:ddcd:cda/1282c19:dd:ec00:c25:c25e:dd:ddcd:cda
2202c19:dd:ec00:c25:c25e:dd:ddcd:cdb/1282c19:dd:ec00:c25:c25e:dd:ddcd:cdb
2212c19:dd:ec00:c25:c25e:dd:ddcd:cdc/1282c19:dd:ec00:c25:c25e:dd:ddcd:cdc
2222c19:dd:ec00:c25:c25e:dd:ddcd:cdd/1282c19:dd:ec00:c25:c25e:dd:ddcd:cdd
2232c19:dd:ec00:c25:c25e:dd:ddcd:cde/1282c19:dd:ec00:c25:c25e:dd:ddcd:cde
2242c19:dd:ec00:c25:c25e:dd:ddcd:cdf/1282c19:dd:ec00:c25:c25e:dd:ddcd:cdf
2252c19:dd:ec00:c25:c25e:dd:ddcd:ce0/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce0
2262c19:dd:ec00:c25:c25e:dd:ddcd:ce1/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce1
2272c19:dd:ec00:c25:c25e:dd:ddcd:ce2/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce2
2282c19:dd:ec00:c25:c25e:dd:ddcd:ce3/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce3
2292c19:dd:ec00:c25:c25e:dd:ddcd:ce4/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce4
2302c19:dd:ec00:c25:c25e:dd:ddcd:ce5/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce5
2312c19:dd:ec00:c25:c25e:dd:ddcd:ce6/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce6
2322c19:dd:ec00:c25:c25e:dd:ddcd:ce7/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce7
2332c19:dd:ec00:c25:c25e:dd:ddcd:ce8/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce8
2342c19:dd:ec00:c25:c25e:dd:ddcd:ce9/1282c19:dd:ec00:c25:c25e:dd:ddcd:ce9
2352c19:dd:ec00:c25:c25e:dd:ddcd:cea/1282c19:dd:ec00:c25:c25e:dd:ddcd:cea
2362c19:dd:ec00:c25:c25e:dd:ddcd:ceb/1282c19:dd:ec00:c25:c25e:dd:ddcd:ceb
2372c19:dd:ec00:c25:c25e:dd:ddcd:cec/1282c19:dd:ec00:c25:c25e:dd:ddcd:cec
2382c19:dd:ec00:c25:c25e:dd:ddcd:ced/1282c19:dd:ec00:c25:c25e:dd:ddcd:ced
2392c19:dd:ec00:c25:c25e:dd:ddcd:cee/1282c19:dd:ec00:c25:c25e:dd:ddcd:cee
2402c19:dd:ec00:c25:c25e:dd:ddcd:cef/1282c19:dd:ec00:c25:c25e:dd:ddcd:cef
2412c19:dd:ec00:c25:c25e:dd:ddcd:cf0/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf0
2422c19:dd:ec00:c25:c25e:dd:ddcd:cf1/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf1
2432c19:dd:ec00:c25:c25e:dd:ddcd:cf2/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf2
2442c19:dd:ec00:c25:c25e:dd:ddcd:cf3/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf3
2452c19:dd:ec00:c25:c25e:dd:ddcd:cf4/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf4
2462c19:dd:ec00:c25:c25e:dd:ddcd:cf5/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf5
2472c19:dd:ec00:c25:c25e:dd:ddcd:cf6/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf6
2482c19:dd:ec00:c25:c25e:dd:ddcd:cf7/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf7
2492c19:dd:ec00:c25:c25e:dd:ddcd:cf8/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf8
2502c19:dd:ec00:c25:c25e:dd:ddcd:cf9/1282c19:dd:ec00:c25:c25e:dd:ddcd:cf9
2512c19:dd:ec00:c25:c25e:dd:ddcd:cfa/1282c19:dd:ec00:c25:c25e:dd:ddcd:cfa
2522c19:dd:ec00:c25:c25e:dd:ddcd:cfb/1282c19:dd:ec00:c25:c25e:dd:ddcd:cfb
2532c19:dd:ec00:c25:c25e:dd:ddcd:cfc/1282c19:dd:ec00:c25:c25e:dd:ddcd:cfc
2542c19:dd:ec00:c25:c25e:dd:ddcd:cfd/1282c19:dd:ec00:c25:c25e:dd:ddcd:cfd
2552c19:dd:ec00:c25:c25e:dd:ddcd:cfe/1282c19:dd:ec00:c25:c25e:dd:ddcd:cfe
2562c19:dd:ec00:c25:c25e:dd:ddcd:cff/1282c19:dd:ec00:c25:c25e:dd:ddcd:cff

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.