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:fe00/120
First address
2c19:dd:d9:dd:c25:c25:94de:fe00
Last address
2c19:dd:d9:dd:c25:c25:94de:feff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:fe00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
e.f.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:fe00/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:fe00/1282c19:dd:d9:dd:c25:c25:94de:fe00
22c19:dd:d9:dd:c25:c25:94de:fe01/1282c19:dd:d9:dd:c25:c25:94de:fe01
32c19:dd:d9:dd:c25:c25:94de:fe02/1282c19:dd:d9:dd:c25:c25:94de:fe02
42c19:dd:d9:dd:c25:c25:94de:fe03/1282c19:dd:d9:dd:c25:c25:94de:fe03
52c19:dd:d9:dd:c25:c25:94de:fe04/1282c19:dd:d9:dd:c25:c25:94de:fe04
62c19:dd:d9:dd:c25:c25:94de:fe05/1282c19:dd:d9:dd:c25:c25:94de:fe05
72c19:dd:d9:dd:c25:c25:94de:fe06/1282c19:dd:d9:dd:c25:c25:94de:fe06
82c19:dd:d9:dd:c25:c25:94de:fe07/1282c19:dd:d9:dd:c25:c25:94de:fe07
92c19:dd:d9:dd:c25:c25:94de:fe08/1282c19:dd:d9:dd:c25:c25:94de:fe08
102c19:dd:d9:dd:c25:c25:94de:fe09/1282c19:dd:d9:dd:c25:c25:94de:fe09
112c19:dd:d9:dd:c25:c25:94de:fe0a/1282c19:dd:d9:dd:c25:c25:94de:fe0a
122c19:dd:d9:dd:c25:c25:94de:fe0b/1282c19:dd:d9:dd:c25:c25:94de:fe0b
132c19:dd:d9:dd:c25:c25:94de:fe0c/1282c19:dd:d9:dd:c25:c25:94de:fe0c
142c19:dd:d9:dd:c25:c25:94de:fe0d/1282c19:dd:d9:dd:c25:c25:94de:fe0d
152c19:dd:d9:dd:c25:c25:94de:fe0e/1282c19:dd:d9:dd:c25:c25:94de:fe0e
162c19:dd:d9:dd:c25:c25:94de:fe0f/1282c19:dd:d9:dd:c25:c25:94de:fe0f
172c19:dd:d9:dd:c25:c25:94de:fe10/1282c19:dd:d9:dd:c25:c25:94de:fe10
182c19:dd:d9:dd:c25:c25:94de:fe11/1282c19:dd:d9:dd:c25:c25:94de:fe11
192c19:dd:d9:dd:c25:c25:94de:fe12/1282c19:dd:d9:dd:c25:c25:94de:fe12
202c19:dd:d9:dd:c25:c25:94de:fe13/1282c19:dd:d9:dd:c25:c25:94de:fe13
212c19:dd:d9:dd:c25:c25:94de:fe14/1282c19:dd:d9:dd:c25:c25:94de:fe14
222c19:dd:d9:dd:c25:c25:94de:fe15/1282c19:dd:d9:dd:c25:c25:94de:fe15
232c19:dd:d9:dd:c25:c25:94de:fe16/1282c19:dd:d9:dd:c25:c25:94de:fe16
242c19:dd:d9:dd:c25:c25:94de:fe17/1282c19:dd:d9:dd:c25:c25:94de:fe17
252c19:dd:d9:dd:c25:c25:94de:fe18/1282c19:dd:d9:dd:c25:c25:94de:fe18
262c19:dd:d9:dd:c25:c25:94de:fe19/1282c19:dd:d9:dd:c25:c25:94de:fe19
272c19:dd:d9:dd:c25:c25:94de:fe1a/1282c19:dd:d9:dd:c25:c25:94de:fe1a
282c19:dd:d9:dd:c25:c25:94de:fe1b/1282c19:dd:d9:dd:c25:c25:94de:fe1b
292c19:dd:d9:dd:c25:c25:94de:fe1c/1282c19:dd:d9:dd:c25:c25:94de:fe1c
302c19:dd:d9:dd:c25:c25:94de:fe1d/1282c19:dd:d9:dd:c25:c25:94de:fe1d
312c19:dd:d9:dd:c25:c25:94de:fe1e/1282c19:dd:d9:dd:c25:c25:94de:fe1e
322c19:dd:d9:dd:c25:c25:94de:fe1f/1282c19:dd:d9:dd:c25:c25:94de:fe1f
332c19:dd:d9:dd:c25:c25:94de:fe20/1282c19:dd:d9:dd:c25:c25:94de:fe20
342c19:dd:d9:dd:c25:c25:94de:fe21/1282c19:dd:d9:dd:c25:c25:94de:fe21
352c19:dd:d9:dd:c25:c25:94de:fe22/1282c19:dd:d9:dd:c25:c25:94de:fe22
362c19:dd:d9:dd:c25:c25:94de:fe23/1282c19:dd:d9:dd:c25:c25:94de:fe23
372c19:dd:d9:dd:c25:c25:94de:fe24/1282c19:dd:d9:dd:c25:c25:94de:fe24
382c19:dd:d9:dd:c25:c25:94de:fe25/1282c19:dd:d9:dd:c25:c25:94de:fe25
392c19:dd:d9:dd:c25:c25:94de:fe26/1282c19:dd:d9:dd:c25:c25:94de:fe26
402c19:dd:d9:dd:c25:c25:94de:fe27/1282c19:dd:d9:dd:c25:c25:94de:fe27
412c19:dd:d9:dd:c25:c25:94de:fe28/1282c19:dd:d9:dd:c25:c25:94de:fe28
422c19:dd:d9:dd:c25:c25:94de:fe29/1282c19:dd:d9:dd:c25:c25:94de:fe29
432c19:dd:d9:dd:c25:c25:94de:fe2a/1282c19:dd:d9:dd:c25:c25:94de:fe2a
442c19:dd:d9:dd:c25:c25:94de:fe2b/1282c19:dd:d9:dd:c25:c25:94de:fe2b
452c19:dd:d9:dd:c25:c25:94de:fe2c/1282c19:dd:d9:dd:c25:c25:94de:fe2c
462c19:dd:d9:dd:c25:c25:94de:fe2d/1282c19:dd:d9:dd:c25:c25:94de:fe2d
472c19:dd:d9:dd:c25:c25:94de:fe2e/1282c19:dd:d9:dd:c25:c25:94de:fe2e
482c19:dd:d9:dd:c25:c25:94de:fe2f/1282c19:dd:d9:dd:c25:c25:94de:fe2f
492c19:dd:d9:dd:c25:c25:94de:fe30/1282c19:dd:d9:dd:c25:c25:94de:fe30
502c19:dd:d9:dd:c25:c25:94de:fe31/1282c19:dd:d9:dd:c25:c25:94de:fe31
512c19:dd:d9:dd:c25:c25:94de:fe32/1282c19:dd:d9:dd:c25:c25:94de:fe32
522c19:dd:d9:dd:c25:c25:94de:fe33/1282c19:dd:d9:dd:c25:c25:94de:fe33
532c19:dd:d9:dd:c25:c25:94de:fe34/1282c19:dd:d9:dd:c25:c25:94de:fe34
542c19:dd:d9:dd:c25:c25:94de:fe35/1282c19:dd:d9:dd:c25:c25:94de:fe35
552c19:dd:d9:dd:c25:c25:94de:fe36/1282c19:dd:d9:dd:c25:c25:94de:fe36
562c19:dd:d9:dd:c25:c25:94de:fe37/1282c19:dd:d9:dd:c25:c25:94de:fe37
572c19:dd:d9:dd:c25:c25:94de:fe38/1282c19:dd:d9:dd:c25:c25:94de:fe38
582c19:dd:d9:dd:c25:c25:94de:fe39/1282c19:dd:d9:dd:c25:c25:94de:fe39
592c19:dd:d9:dd:c25:c25:94de:fe3a/1282c19:dd:d9:dd:c25:c25:94de:fe3a
602c19:dd:d9:dd:c25:c25:94de:fe3b/1282c19:dd:d9:dd:c25:c25:94de:fe3b
612c19:dd:d9:dd:c25:c25:94de:fe3c/1282c19:dd:d9:dd:c25:c25:94de:fe3c
622c19:dd:d9:dd:c25:c25:94de:fe3d/1282c19:dd:d9:dd:c25:c25:94de:fe3d
632c19:dd:d9:dd:c25:c25:94de:fe3e/1282c19:dd:d9:dd:c25:c25:94de:fe3e
642c19:dd:d9:dd:c25:c25:94de:fe3f/1282c19:dd:d9:dd:c25:c25:94de:fe3f
652c19:dd:d9:dd:c25:c25:94de:fe40/1282c19:dd:d9:dd:c25:c25:94de:fe40
662c19:dd:d9:dd:c25:c25:94de:fe41/1282c19:dd:d9:dd:c25:c25:94de:fe41
672c19:dd:d9:dd:c25:c25:94de:fe42/1282c19:dd:d9:dd:c25:c25:94de:fe42
682c19:dd:d9:dd:c25:c25:94de:fe43/1282c19:dd:d9:dd:c25:c25:94de:fe43
692c19:dd:d9:dd:c25:c25:94de:fe44/1282c19:dd:d9:dd:c25:c25:94de:fe44
702c19:dd:d9:dd:c25:c25:94de:fe45/1282c19:dd:d9:dd:c25:c25:94de:fe45
712c19:dd:d9:dd:c25:c25:94de:fe46/1282c19:dd:d9:dd:c25:c25:94de:fe46
722c19:dd:d9:dd:c25:c25:94de:fe47/1282c19:dd:d9:dd:c25:c25:94de:fe47
732c19:dd:d9:dd:c25:c25:94de:fe48/1282c19:dd:d9:dd:c25:c25:94de:fe48
742c19:dd:d9:dd:c25:c25:94de:fe49/1282c19:dd:d9:dd:c25:c25:94de:fe49
752c19:dd:d9:dd:c25:c25:94de:fe4a/1282c19:dd:d9:dd:c25:c25:94de:fe4a
762c19:dd:d9:dd:c25:c25:94de:fe4b/1282c19:dd:d9:dd:c25:c25:94de:fe4b
772c19:dd:d9:dd:c25:c25:94de:fe4c/1282c19:dd:d9:dd:c25:c25:94de:fe4c
782c19:dd:d9:dd:c25:c25:94de:fe4d/1282c19:dd:d9:dd:c25:c25:94de:fe4d
792c19:dd:d9:dd:c25:c25:94de:fe4e/1282c19:dd:d9:dd:c25:c25:94de:fe4e
802c19:dd:d9:dd:c25:c25:94de:fe4f/1282c19:dd:d9:dd:c25:c25:94de:fe4f
812c19:dd:d9:dd:c25:c25:94de:fe50/1282c19:dd:d9:dd:c25:c25:94de:fe50
822c19:dd:d9:dd:c25:c25:94de:fe51/1282c19:dd:d9:dd:c25:c25:94de:fe51
832c19:dd:d9:dd:c25:c25:94de:fe52/1282c19:dd:d9:dd:c25:c25:94de:fe52
842c19:dd:d9:dd:c25:c25:94de:fe53/1282c19:dd:d9:dd:c25:c25:94de:fe53
852c19:dd:d9:dd:c25:c25:94de:fe54/1282c19:dd:d9:dd:c25:c25:94de:fe54
862c19:dd:d9:dd:c25:c25:94de:fe55/1282c19:dd:d9:dd:c25:c25:94de:fe55
872c19:dd:d9:dd:c25:c25:94de:fe56/1282c19:dd:d9:dd:c25:c25:94de:fe56
882c19:dd:d9:dd:c25:c25:94de:fe57/1282c19:dd:d9:dd:c25:c25:94de:fe57
892c19:dd:d9:dd:c25:c25:94de:fe58/1282c19:dd:d9:dd:c25:c25:94de:fe58
902c19:dd:d9:dd:c25:c25:94de:fe59/1282c19:dd:d9:dd:c25:c25:94de:fe59
912c19:dd:d9:dd:c25:c25:94de:fe5a/1282c19:dd:d9:dd:c25:c25:94de:fe5a
922c19:dd:d9:dd:c25:c25:94de:fe5b/1282c19:dd:d9:dd:c25:c25:94de:fe5b
932c19:dd:d9:dd:c25:c25:94de:fe5c/1282c19:dd:d9:dd:c25:c25:94de:fe5c
942c19:dd:d9:dd:c25:c25:94de:fe5d/1282c19:dd:d9:dd:c25:c25:94de:fe5d
952c19:dd:d9:dd:c25:c25:94de:fe5e/1282c19:dd:d9:dd:c25:c25:94de:fe5e
962c19:dd:d9:dd:c25:c25:94de:fe5f/1282c19:dd:d9:dd:c25:c25:94de:fe5f
972c19:dd:d9:dd:c25:c25:94de:fe60/1282c19:dd:d9:dd:c25:c25:94de:fe60
982c19:dd:d9:dd:c25:c25:94de:fe61/1282c19:dd:d9:dd:c25:c25:94de:fe61
992c19:dd:d9:dd:c25:c25:94de:fe62/1282c19:dd:d9:dd:c25:c25:94de:fe62
1002c19:dd:d9:dd:c25:c25:94de:fe63/1282c19:dd:d9:dd:c25:c25:94de:fe63
1012c19:dd:d9:dd:c25:c25:94de:fe64/1282c19:dd:d9:dd:c25:c25:94de:fe64
1022c19:dd:d9:dd:c25:c25:94de:fe65/1282c19:dd:d9:dd:c25:c25:94de:fe65
1032c19:dd:d9:dd:c25:c25:94de:fe66/1282c19:dd:d9:dd:c25:c25:94de:fe66
1042c19:dd:d9:dd:c25:c25:94de:fe67/1282c19:dd:d9:dd:c25:c25:94de:fe67
1052c19:dd:d9:dd:c25:c25:94de:fe68/1282c19:dd:d9:dd:c25:c25:94de:fe68
1062c19:dd:d9:dd:c25:c25:94de:fe69/1282c19:dd:d9:dd:c25:c25:94de:fe69
1072c19:dd:d9:dd:c25:c25:94de:fe6a/1282c19:dd:d9:dd:c25:c25:94de:fe6a
1082c19:dd:d9:dd:c25:c25:94de:fe6b/1282c19:dd:d9:dd:c25:c25:94de:fe6b
1092c19:dd:d9:dd:c25:c25:94de:fe6c/1282c19:dd:d9:dd:c25:c25:94de:fe6c
1102c19:dd:d9:dd:c25:c25:94de:fe6d/1282c19:dd:d9:dd:c25:c25:94de:fe6d
1112c19:dd:d9:dd:c25:c25:94de:fe6e/1282c19:dd:d9:dd:c25:c25:94de:fe6e
1122c19:dd:d9:dd:c25:c25:94de:fe6f/1282c19:dd:d9:dd:c25:c25:94de:fe6f
1132c19:dd:d9:dd:c25:c25:94de:fe70/1282c19:dd:d9:dd:c25:c25:94de:fe70
1142c19:dd:d9:dd:c25:c25:94de:fe71/1282c19:dd:d9:dd:c25:c25:94de:fe71
1152c19:dd:d9:dd:c25:c25:94de:fe72/1282c19:dd:d9:dd:c25:c25:94de:fe72
1162c19:dd:d9:dd:c25:c25:94de:fe73/1282c19:dd:d9:dd:c25:c25:94de:fe73
1172c19:dd:d9:dd:c25:c25:94de:fe74/1282c19:dd:d9:dd:c25:c25:94de:fe74
1182c19:dd:d9:dd:c25:c25:94de:fe75/1282c19:dd:d9:dd:c25:c25:94de:fe75
1192c19:dd:d9:dd:c25:c25:94de:fe76/1282c19:dd:d9:dd:c25:c25:94de:fe76
1202c19:dd:d9:dd:c25:c25:94de:fe77/1282c19:dd:d9:dd:c25:c25:94de:fe77
1212c19:dd:d9:dd:c25:c25:94de:fe78/1282c19:dd:d9:dd:c25:c25:94de:fe78
1222c19:dd:d9:dd:c25:c25:94de:fe79/1282c19:dd:d9:dd:c25:c25:94de:fe79
1232c19:dd:d9:dd:c25:c25:94de:fe7a/1282c19:dd:d9:dd:c25:c25:94de:fe7a
1242c19:dd:d9:dd:c25:c25:94de:fe7b/1282c19:dd:d9:dd:c25:c25:94de:fe7b
1252c19:dd:d9:dd:c25:c25:94de:fe7c/1282c19:dd:d9:dd:c25:c25:94de:fe7c
1262c19:dd:d9:dd:c25:c25:94de:fe7d/1282c19:dd:d9:dd:c25:c25:94de:fe7d
1272c19:dd:d9:dd:c25:c25:94de:fe7e/1282c19:dd:d9:dd:c25:c25:94de:fe7e
1282c19:dd:d9:dd:c25:c25:94de:fe7f/1282c19:dd:d9:dd:c25:c25:94de:fe7f
1292c19:dd:d9:dd:c25:c25:94de:fe80/1282c19:dd:d9:dd:c25:c25:94de:fe80
1302c19:dd:d9:dd:c25:c25:94de:fe81/1282c19:dd:d9:dd:c25:c25:94de:fe81
1312c19:dd:d9:dd:c25:c25:94de:fe82/1282c19:dd:d9:dd:c25:c25:94de:fe82
1322c19:dd:d9:dd:c25:c25:94de:fe83/1282c19:dd:d9:dd:c25:c25:94de:fe83
1332c19:dd:d9:dd:c25:c25:94de:fe84/1282c19:dd:d9:dd:c25:c25:94de:fe84
1342c19:dd:d9:dd:c25:c25:94de:fe85/1282c19:dd:d9:dd:c25:c25:94de:fe85
1352c19:dd:d9:dd:c25:c25:94de:fe86/1282c19:dd:d9:dd:c25:c25:94de:fe86
1362c19:dd:d9:dd:c25:c25:94de:fe87/1282c19:dd:d9:dd:c25:c25:94de:fe87
1372c19:dd:d9:dd:c25:c25:94de:fe88/1282c19:dd:d9:dd:c25:c25:94de:fe88
1382c19:dd:d9:dd:c25:c25:94de:fe89/1282c19:dd:d9:dd:c25:c25:94de:fe89
1392c19:dd:d9:dd:c25:c25:94de:fe8a/1282c19:dd:d9:dd:c25:c25:94de:fe8a
1402c19:dd:d9:dd:c25:c25:94de:fe8b/1282c19:dd:d9:dd:c25:c25:94de:fe8b
1412c19:dd:d9:dd:c25:c25:94de:fe8c/1282c19:dd:d9:dd:c25:c25:94de:fe8c
1422c19:dd:d9:dd:c25:c25:94de:fe8d/1282c19:dd:d9:dd:c25:c25:94de:fe8d
1432c19:dd:d9:dd:c25:c25:94de:fe8e/1282c19:dd:d9:dd:c25:c25:94de:fe8e
1442c19:dd:d9:dd:c25:c25:94de:fe8f/1282c19:dd:d9:dd:c25:c25:94de:fe8f
1452c19:dd:d9:dd:c25:c25:94de:fe90/1282c19:dd:d9:dd:c25:c25:94de:fe90
1462c19:dd:d9:dd:c25:c25:94de:fe91/1282c19:dd:d9:dd:c25:c25:94de:fe91
1472c19:dd:d9:dd:c25:c25:94de:fe92/1282c19:dd:d9:dd:c25:c25:94de:fe92
1482c19:dd:d9:dd:c25:c25:94de:fe93/1282c19:dd:d9:dd:c25:c25:94de:fe93
1492c19:dd:d9:dd:c25:c25:94de:fe94/1282c19:dd:d9:dd:c25:c25:94de:fe94
1502c19:dd:d9:dd:c25:c25:94de:fe95/1282c19:dd:d9:dd:c25:c25:94de:fe95
1512c19:dd:d9:dd:c25:c25:94de:fe96/1282c19:dd:d9:dd:c25:c25:94de:fe96
1522c19:dd:d9:dd:c25:c25:94de:fe97/1282c19:dd:d9:dd:c25:c25:94de:fe97
1532c19:dd:d9:dd:c25:c25:94de:fe98/1282c19:dd:d9:dd:c25:c25:94de:fe98
1542c19:dd:d9:dd:c25:c25:94de:fe99/1282c19:dd:d9:dd:c25:c25:94de:fe99
1552c19:dd:d9:dd:c25:c25:94de:fe9a/1282c19:dd:d9:dd:c25:c25:94de:fe9a
1562c19:dd:d9:dd:c25:c25:94de:fe9b/1282c19:dd:d9:dd:c25:c25:94de:fe9b
1572c19:dd:d9:dd:c25:c25:94de:fe9c/1282c19:dd:d9:dd:c25:c25:94de:fe9c
1582c19:dd:d9:dd:c25:c25:94de:fe9d/1282c19:dd:d9:dd:c25:c25:94de:fe9d
1592c19:dd:d9:dd:c25:c25:94de:fe9e/1282c19:dd:d9:dd:c25:c25:94de:fe9e
1602c19:dd:d9:dd:c25:c25:94de:fe9f/1282c19:dd:d9:dd:c25:c25:94de:fe9f
1612c19:dd:d9:dd:c25:c25:94de:fea0/1282c19:dd:d9:dd:c25:c25:94de:fea0
1622c19:dd:d9:dd:c25:c25:94de:fea1/1282c19:dd:d9:dd:c25:c25:94de:fea1
1632c19:dd:d9:dd:c25:c25:94de:fea2/1282c19:dd:d9:dd:c25:c25:94de:fea2
1642c19:dd:d9:dd:c25:c25:94de:fea3/1282c19:dd:d9:dd:c25:c25:94de:fea3
1652c19:dd:d9:dd:c25:c25:94de:fea4/1282c19:dd:d9:dd:c25:c25:94de:fea4
1662c19:dd:d9:dd:c25:c25:94de:fea5/1282c19:dd:d9:dd:c25:c25:94de:fea5
1672c19:dd:d9:dd:c25:c25:94de:fea6/1282c19:dd:d9:dd:c25:c25:94de:fea6
1682c19:dd:d9:dd:c25:c25:94de:fea7/1282c19:dd:d9:dd:c25:c25:94de:fea7
1692c19:dd:d9:dd:c25:c25:94de:fea8/1282c19:dd:d9:dd:c25:c25:94de:fea8
1702c19:dd:d9:dd:c25:c25:94de:fea9/1282c19:dd:d9:dd:c25:c25:94de:fea9
1712c19:dd:d9:dd:c25:c25:94de:feaa/1282c19:dd:d9:dd:c25:c25:94de:feaa
1722c19:dd:d9:dd:c25:c25:94de:feab/1282c19:dd:d9:dd:c25:c25:94de:feab
1732c19:dd:d9:dd:c25:c25:94de:feac/1282c19:dd:d9:dd:c25:c25:94de:feac
1742c19:dd:d9:dd:c25:c25:94de:fead/1282c19:dd:d9:dd:c25:c25:94de:fead
1752c19:dd:d9:dd:c25:c25:94de:feae/1282c19:dd:d9:dd:c25:c25:94de:feae
1762c19:dd:d9:dd:c25:c25:94de:feaf/1282c19:dd:d9:dd:c25:c25:94de:feaf
1772c19:dd:d9:dd:c25:c25:94de:feb0/1282c19:dd:d9:dd:c25:c25:94de:feb0
1782c19:dd:d9:dd:c25:c25:94de:feb1/1282c19:dd:d9:dd:c25:c25:94de:feb1
1792c19:dd:d9:dd:c25:c25:94de:feb2/1282c19:dd:d9:dd:c25:c25:94de:feb2
1802c19:dd:d9:dd:c25:c25:94de:feb3/1282c19:dd:d9:dd:c25:c25:94de:feb3
1812c19:dd:d9:dd:c25:c25:94de:feb4/1282c19:dd:d9:dd:c25:c25:94de:feb4
1822c19:dd:d9:dd:c25:c25:94de:feb5/1282c19:dd:d9:dd:c25:c25:94de:feb5
1832c19:dd:d9:dd:c25:c25:94de:feb6/1282c19:dd:d9:dd:c25:c25:94de:feb6
1842c19:dd:d9:dd:c25:c25:94de:feb7/1282c19:dd:d9:dd:c25:c25:94de:feb7
1852c19:dd:d9:dd:c25:c25:94de:feb8/1282c19:dd:d9:dd:c25:c25:94de:feb8
1862c19:dd:d9:dd:c25:c25:94de:feb9/1282c19:dd:d9:dd:c25:c25:94de:feb9
1872c19:dd:d9:dd:c25:c25:94de:feba/1282c19:dd:d9:dd:c25:c25:94de:feba
1882c19:dd:d9:dd:c25:c25:94de:febb/1282c19:dd:d9:dd:c25:c25:94de:febb
1892c19:dd:d9:dd:c25:c25:94de:febc/1282c19:dd:d9:dd:c25:c25:94de:febc
1902c19:dd:d9:dd:c25:c25:94de:febd/1282c19:dd:d9:dd:c25:c25:94de:febd
1912c19:dd:d9:dd:c25:c25:94de:febe/1282c19:dd:d9:dd:c25:c25:94de:febe
1922c19:dd:d9:dd:c25:c25:94de:febf/1282c19:dd:d9:dd:c25:c25:94de:febf
1932c19:dd:d9:dd:c25:c25:94de:fec0/1282c19:dd:d9:dd:c25:c25:94de:fec0
1942c19:dd:d9:dd:c25:c25:94de:fec1/1282c19:dd:d9:dd:c25:c25:94de:fec1
1952c19:dd:d9:dd:c25:c25:94de:fec2/1282c19:dd:d9:dd:c25:c25:94de:fec2
1962c19:dd:d9:dd:c25:c25:94de:fec3/1282c19:dd:d9:dd:c25:c25:94de:fec3
1972c19:dd:d9:dd:c25:c25:94de:fec4/1282c19:dd:d9:dd:c25:c25:94de:fec4
1982c19:dd:d9:dd:c25:c25:94de:fec5/1282c19:dd:d9:dd:c25:c25:94de:fec5
1992c19:dd:d9:dd:c25:c25:94de:fec6/1282c19:dd:d9:dd:c25:c25:94de:fec6
2002c19:dd:d9:dd:c25:c25:94de:fec7/1282c19:dd:d9:dd:c25:c25:94de:fec7
2012c19:dd:d9:dd:c25:c25:94de:fec8/1282c19:dd:d9:dd:c25:c25:94de:fec8
2022c19:dd:d9:dd:c25:c25:94de:fec9/1282c19:dd:d9:dd:c25:c25:94de:fec9
2032c19:dd:d9:dd:c25:c25:94de:feca/1282c19:dd:d9:dd:c25:c25:94de:feca
2042c19:dd:d9:dd:c25:c25:94de:fecb/1282c19:dd:d9:dd:c25:c25:94de:fecb
2052c19:dd:d9:dd:c25:c25:94de:fecc/1282c19:dd:d9:dd:c25:c25:94de:fecc
2062c19:dd:d9:dd:c25:c25:94de:fecd/1282c19:dd:d9:dd:c25:c25:94de:fecd
2072c19:dd:d9:dd:c25:c25:94de:fece/1282c19:dd:d9:dd:c25:c25:94de:fece
2082c19:dd:d9:dd:c25:c25:94de:fecf/1282c19:dd:d9:dd:c25:c25:94de:fecf
2092c19:dd:d9:dd:c25:c25:94de:fed0/1282c19:dd:d9:dd:c25:c25:94de:fed0
2102c19:dd:d9:dd:c25:c25:94de:fed1/1282c19:dd:d9:dd:c25:c25:94de:fed1
2112c19:dd:d9:dd:c25:c25:94de:fed2/1282c19:dd:d9:dd:c25:c25:94de:fed2
2122c19:dd:d9:dd:c25:c25:94de:fed3/1282c19:dd:d9:dd:c25:c25:94de:fed3
2132c19:dd:d9:dd:c25:c25:94de:fed4/1282c19:dd:d9:dd:c25:c25:94de:fed4
2142c19:dd:d9:dd:c25:c25:94de:fed5/1282c19:dd:d9:dd:c25:c25:94de:fed5
2152c19:dd:d9:dd:c25:c25:94de:fed6/1282c19:dd:d9:dd:c25:c25:94de:fed6
2162c19:dd:d9:dd:c25:c25:94de:fed7/1282c19:dd:d9:dd:c25:c25:94de:fed7
2172c19:dd:d9:dd:c25:c25:94de:fed8/1282c19:dd:d9:dd:c25:c25:94de:fed8
2182c19:dd:d9:dd:c25:c25:94de:fed9/1282c19:dd:d9:dd:c25:c25:94de:fed9
2192c19:dd:d9:dd:c25:c25:94de:feda/1282c19:dd:d9:dd:c25:c25:94de:feda
2202c19:dd:d9:dd:c25:c25:94de:fedb/1282c19:dd:d9:dd:c25:c25:94de:fedb
2212c19:dd:d9:dd:c25:c25:94de:fedc/1282c19:dd:d9:dd:c25:c25:94de:fedc
2222c19:dd:d9:dd:c25:c25:94de:fedd/1282c19:dd:d9:dd:c25:c25:94de:fedd
2232c19:dd:d9:dd:c25:c25:94de:fede/1282c19:dd:d9:dd:c25:c25:94de:fede
2242c19:dd:d9:dd:c25:c25:94de:fedf/1282c19:dd:d9:dd:c25:c25:94de:fedf
2252c19:dd:d9:dd:c25:c25:94de:fee0/1282c19:dd:d9:dd:c25:c25:94de:fee0
2262c19:dd:d9:dd:c25:c25:94de:fee1/1282c19:dd:d9:dd:c25:c25:94de:fee1
2272c19:dd:d9:dd:c25:c25:94de:fee2/1282c19:dd:d9:dd:c25:c25:94de:fee2
2282c19:dd:d9:dd:c25:c25:94de:fee3/1282c19:dd:d9:dd:c25:c25:94de:fee3
2292c19:dd:d9:dd:c25:c25:94de:fee4/1282c19:dd:d9:dd:c25:c25:94de:fee4
2302c19:dd:d9:dd:c25:c25:94de:fee5/1282c19:dd:d9:dd:c25:c25:94de:fee5
2312c19:dd:d9:dd:c25:c25:94de:fee6/1282c19:dd:d9:dd:c25:c25:94de:fee6
2322c19:dd:d9:dd:c25:c25:94de:fee7/1282c19:dd:d9:dd:c25:c25:94de:fee7
2332c19:dd:d9:dd:c25:c25:94de:fee8/1282c19:dd:d9:dd:c25:c25:94de:fee8
2342c19:dd:d9:dd:c25:c25:94de:fee9/1282c19:dd:d9:dd:c25:c25:94de:fee9
2352c19:dd:d9:dd:c25:c25:94de:feea/1282c19:dd:d9:dd:c25:c25:94de:feea
2362c19:dd:d9:dd:c25:c25:94de:feeb/1282c19:dd:d9:dd:c25:c25:94de:feeb
2372c19:dd:d9:dd:c25:c25:94de:feec/1282c19:dd:d9:dd:c25:c25:94de:feec
2382c19:dd:d9:dd:c25:c25:94de:feed/1282c19:dd:d9:dd:c25:c25:94de:feed
2392c19:dd:d9:dd:c25:c25:94de:feee/1282c19:dd:d9:dd:c25:c25:94de:feee
2402c19:dd:d9:dd:c25:c25:94de:feef/1282c19:dd:d9:dd:c25:c25:94de:feef
2412c19:dd:d9:dd:c25:c25:94de:fef0/1282c19:dd:d9:dd:c25:c25:94de:fef0
2422c19:dd:d9:dd:c25:c25:94de:fef1/1282c19:dd:d9:dd:c25:c25:94de:fef1
2432c19:dd:d9:dd:c25:c25:94de:fef2/1282c19:dd:d9:dd:c25:c25:94de:fef2
2442c19:dd:d9:dd:c25:c25:94de:fef3/1282c19:dd:d9:dd:c25:c25:94de:fef3
2452c19:dd:d9:dd:c25:c25:94de:fef4/1282c19:dd:d9:dd:c25:c25:94de:fef4
2462c19:dd:d9:dd:c25:c25:94de:fef5/1282c19:dd:d9:dd:c25:c25:94de:fef5
2472c19:dd:d9:dd:c25:c25:94de:fef6/1282c19:dd:d9:dd:c25:c25:94de:fef6
2482c19:dd:d9:dd:c25:c25:94de:fef7/1282c19:dd:d9:dd:c25:c25:94de:fef7
2492c19:dd:d9:dd:c25:c25:94de:fef8/1282c19:dd:d9:dd:c25:c25:94de:fef8
2502c19:dd:d9:dd:c25:c25:94de:fef9/1282c19:dd:d9:dd:c25:c25:94de:fef9
2512c19:dd:d9:dd:c25:c25:94de:fefa/1282c19:dd:d9:dd:c25:c25:94de:fefa
2522c19:dd:d9:dd:c25:c25:94de:fefb/1282c19:dd:d9:dd:c25:c25:94de:fefb
2532c19:dd:d9:dd:c25:c25:94de:fefc/1282c19:dd:d9:dd:c25:c25:94de:fefc
2542c19:dd:d9:dd:c25:c25:94de:fefd/1282c19:dd:d9:dd:c25:c25:94de:fefd
2552c19:dd:d9:dd:c25:c25:94de:fefe/1282c19:dd:d9:dd:c25:c25:94de:fefe
2562c19:dd:d9:dd:c25:c25:94de:feff/1282c19:dd:d9:dd:c25:c25:94de:feff

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.