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/118
Addresses1,024
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:d915:fc00/118
First address
2c19:dd:d9:dd:c25:c25:d915:fc00
Last address
2c19:dd:d9:dd:c25:c25:d915:ffff
Addresses
1,024
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:d915:fc00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
c.f.5.1.9.d.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
d.f.5.1.9.d.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
e.f.5.1.9.d.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
f.f.5.1.9.d.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
/118 is not on a 4-bit boundary, so it takes 4 /120 zones.
Split into smaller subnets/128
/119 (2)/120 (4)/121 (8)/122 (16)/124 (64)/127 (512)/128 (1,024)

2c19:dd:d9:dd:c25:c25:d915:fc00/118 makes 1,024 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:d915:fc00/1282c19:dd:d9:dd:c25:c25:d915:fc00
22c19:dd:d9:dd:c25:c25:d915:fc01/1282c19:dd:d9:dd:c25:c25:d915:fc01
32c19:dd:d9:dd:c25:c25:d915:fc02/1282c19:dd:d9:dd:c25:c25:d915:fc02
42c19:dd:d9:dd:c25:c25:d915:fc03/1282c19:dd:d9:dd:c25:c25:d915:fc03
52c19:dd:d9:dd:c25:c25:d915:fc04/1282c19:dd:d9:dd:c25:c25:d915:fc04
62c19:dd:d9:dd:c25:c25:d915:fc05/1282c19:dd:d9:dd:c25:c25:d915:fc05
72c19:dd:d9:dd:c25:c25:d915:fc06/1282c19:dd:d9:dd:c25:c25:d915:fc06
82c19:dd:d9:dd:c25:c25:d915:fc07/1282c19:dd:d9:dd:c25:c25:d915:fc07
92c19:dd:d9:dd:c25:c25:d915:fc08/1282c19:dd:d9:dd:c25:c25:d915:fc08
102c19:dd:d9:dd:c25:c25:d915:fc09/1282c19:dd:d9:dd:c25:c25:d915:fc09
112c19:dd:d9:dd:c25:c25:d915:fc0a/1282c19:dd:d9:dd:c25:c25:d915:fc0a
122c19:dd:d9:dd:c25:c25:d915:fc0b/1282c19:dd:d9:dd:c25:c25:d915:fc0b
132c19:dd:d9:dd:c25:c25:d915:fc0c/1282c19:dd:d9:dd:c25:c25:d915:fc0c
142c19:dd:d9:dd:c25:c25:d915:fc0d/1282c19:dd:d9:dd:c25:c25:d915:fc0d
152c19:dd:d9:dd:c25:c25:d915:fc0e/1282c19:dd:d9:dd:c25:c25:d915:fc0e
162c19:dd:d9:dd:c25:c25:d915:fc0f/1282c19:dd:d9:dd:c25:c25:d915:fc0f
172c19:dd:d9:dd:c25:c25:d915:fc10/1282c19:dd:d9:dd:c25:c25:d915:fc10
182c19:dd:d9:dd:c25:c25:d915:fc11/1282c19:dd:d9:dd:c25:c25:d915:fc11
192c19:dd:d9:dd:c25:c25:d915:fc12/1282c19:dd:d9:dd:c25:c25:d915:fc12
202c19:dd:d9:dd:c25:c25:d915:fc13/1282c19:dd:d9:dd:c25:c25:d915:fc13
212c19:dd:d9:dd:c25:c25:d915:fc14/1282c19:dd:d9:dd:c25:c25:d915:fc14
222c19:dd:d9:dd:c25:c25:d915:fc15/1282c19:dd:d9:dd:c25:c25:d915:fc15
232c19:dd:d9:dd:c25:c25:d915:fc16/1282c19:dd:d9:dd:c25:c25:d915:fc16
242c19:dd:d9:dd:c25:c25:d915:fc17/1282c19:dd:d9:dd:c25:c25:d915:fc17
252c19:dd:d9:dd:c25:c25:d915:fc18/1282c19:dd:d9:dd:c25:c25:d915:fc18
262c19:dd:d9:dd:c25:c25:d915:fc19/1282c19:dd:d9:dd:c25:c25:d915:fc19
272c19:dd:d9:dd:c25:c25:d915:fc1a/1282c19:dd:d9:dd:c25:c25:d915:fc1a
282c19:dd:d9:dd:c25:c25:d915:fc1b/1282c19:dd:d9:dd:c25:c25:d915:fc1b
292c19:dd:d9:dd:c25:c25:d915:fc1c/1282c19:dd:d9:dd:c25:c25:d915:fc1c
302c19:dd:d9:dd:c25:c25:d915:fc1d/1282c19:dd:d9:dd:c25:c25:d915:fc1d
312c19:dd:d9:dd:c25:c25:d915:fc1e/1282c19:dd:d9:dd:c25:c25:d915:fc1e
322c19:dd:d9:dd:c25:c25:d915:fc1f/1282c19:dd:d9:dd:c25:c25:d915:fc1f
332c19:dd:d9:dd:c25:c25:d915:fc20/1282c19:dd:d9:dd:c25:c25:d915:fc20
342c19:dd:d9:dd:c25:c25:d915:fc21/1282c19:dd:d9:dd:c25:c25:d915:fc21
352c19:dd:d9:dd:c25:c25:d915:fc22/1282c19:dd:d9:dd:c25:c25:d915:fc22
362c19:dd:d9:dd:c25:c25:d915:fc23/1282c19:dd:d9:dd:c25:c25:d915:fc23
372c19:dd:d9:dd:c25:c25:d915:fc24/1282c19:dd:d9:dd:c25:c25:d915:fc24
382c19:dd:d9:dd:c25:c25:d915:fc25/1282c19:dd:d9:dd:c25:c25:d915:fc25
392c19:dd:d9:dd:c25:c25:d915:fc26/1282c19:dd:d9:dd:c25:c25:d915:fc26
402c19:dd:d9:dd:c25:c25:d915:fc27/1282c19:dd:d9:dd:c25:c25:d915:fc27
412c19:dd:d9:dd:c25:c25:d915:fc28/1282c19:dd:d9:dd:c25:c25:d915:fc28
422c19:dd:d9:dd:c25:c25:d915:fc29/1282c19:dd:d9:dd:c25:c25:d915:fc29
432c19:dd:d9:dd:c25:c25:d915:fc2a/1282c19:dd:d9:dd:c25:c25:d915:fc2a
442c19:dd:d9:dd:c25:c25:d915:fc2b/1282c19:dd:d9:dd:c25:c25:d915:fc2b
452c19:dd:d9:dd:c25:c25:d915:fc2c/1282c19:dd:d9:dd:c25:c25:d915:fc2c
462c19:dd:d9:dd:c25:c25:d915:fc2d/1282c19:dd:d9:dd:c25:c25:d915:fc2d
472c19:dd:d9:dd:c25:c25:d915:fc2e/1282c19:dd:d9:dd:c25:c25:d915:fc2e
482c19:dd:d9:dd:c25:c25:d915:fc2f/1282c19:dd:d9:dd:c25:c25:d915:fc2f
492c19:dd:d9:dd:c25:c25:d915:fc30/1282c19:dd:d9:dd:c25:c25:d915:fc30
502c19:dd:d9:dd:c25:c25:d915:fc31/1282c19:dd:d9:dd:c25:c25:d915:fc31
512c19:dd:d9:dd:c25:c25:d915:fc32/1282c19:dd:d9:dd:c25:c25:d915:fc32
522c19:dd:d9:dd:c25:c25:d915:fc33/1282c19:dd:d9:dd:c25:c25:d915:fc33
532c19:dd:d9:dd:c25:c25:d915:fc34/1282c19:dd:d9:dd:c25:c25:d915:fc34
542c19:dd:d9:dd:c25:c25:d915:fc35/1282c19:dd:d9:dd:c25:c25:d915:fc35
552c19:dd:d9:dd:c25:c25:d915:fc36/1282c19:dd:d9:dd:c25:c25:d915:fc36
562c19:dd:d9:dd:c25:c25:d915:fc37/1282c19:dd:d9:dd:c25:c25:d915:fc37
572c19:dd:d9:dd:c25:c25:d915:fc38/1282c19:dd:d9:dd:c25:c25:d915:fc38
582c19:dd:d9:dd:c25:c25:d915:fc39/1282c19:dd:d9:dd:c25:c25:d915:fc39
592c19:dd:d9:dd:c25:c25:d915:fc3a/1282c19:dd:d9:dd:c25:c25:d915:fc3a
602c19:dd:d9:dd:c25:c25:d915:fc3b/1282c19:dd:d9:dd:c25:c25:d915:fc3b
612c19:dd:d9:dd:c25:c25:d915:fc3c/1282c19:dd:d9:dd:c25:c25:d915:fc3c
622c19:dd:d9:dd:c25:c25:d915:fc3d/1282c19:dd:d9:dd:c25:c25:d915:fc3d
632c19:dd:d9:dd:c25:c25:d915:fc3e/1282c19:dd:d9:dd:c25:c25:d915:fc3e
642c19:dd:d9:dd:c25:c25:d915:fc3f/1282c19:dd:d9:dd:c25:c25:d915:fc3f
652c19:dd:d9:dd:c25:c25:d915:fc40/1282c19:dd:d9:dd:c25:c25:d915:fc40
662c19:dd:d9:dd:c25:c25:d915:fc41/1282c19:dd:d9:dd:c25:c25:d915:fc41
672c19:dd:d9:dd:c25:c25:d915:fc42/1282c19:dd:d9:dd:c25:c25:d915:fc42
682c19:dd:d9:dd:c25:c25:d915:fc43/1282c19:dd:d9:dd:c25:c25:d915:fc43
692c19:dd:d9:dd:c25:c25:d915:fc44/1282c19:dd:d9:dd:c25:c25:d915:fc44
702c19:dd:d9:dd:c25:c25:d915:fc45/1282c19:dd:d9:dd:c25:c25:d915:fc45
712c19:dd:d9:dd:c25:c25:d915:fc46/1282c19:dd:d9:dd:c25:c25:d915:fc46
722c19:dd:d9:dd:c25:c25:d915:fc47/1282c19:dd:d9:dd:c25:c25:d915:fc47
732c19:dd:d9:dd:c25:c25:d915:fc48/1282c19:dd:d9:dd:c25:c25:d915:fc48
742c19:dd:d9:dd:c25:c25:d915:fc49/1282c19:dd:d9:dd:c25:c25:d915:fc49
752c19:dd:d9:dd:c25:c25:d915:fc4a/1282c19:dd:d9:dd:c25:c25:d915:fc4a
762c19:dd:d9:dd:c25:c25:d915:fc4b/1282c19:dd:d9:dd:c25:c25:d915:fc4b
772c19:dd:d9:dd:c25:c25:d915:fc4c/1282c19:dd:d9:dd:c25:c25:d915:fc4c
782c19:dd:d9:dd:c25:c25:d915:fc4d/1282c19:dd:d9:dd:c25:c25:d915:fc4d
792c19:dd:d9:dd:c25:c25:d915:fc4e/1282c19:dd:d9:dd:c25:c25:d915:fc4e
802c19:dd:d9:dd:c25:c25:d915:fc4f/1282c19:dd:d9:dd:c25:c25:d915:fc4f
812c19:dd:d9:dd:c25:c25:d915:fc50/1282c19:dd:d9:dd:c25:c25:d915:fc50
822c19:dd:d9:dd:c25:c25:d915:fc51/1282c19:dd:d9:dd:c25:c25:d915:fc51
832c19:dd:d9:dd:c25:c25:d915:fc52/1282c19:dd:d9:dd:c25:c25:d915:fc52
842c19:dd:d9:dd:c25:c25:d915:fc53/1282c19:dd:d9:dd:c25:c25:d915:fc53
852c19:dd:d9:dd:c25:c25:d915:fc54/1282c19:dd:d9:dd:c25:c25:d915:fc54
862c19:dd:d9:dd:c25:c25:d915:fc55/1282c19:dd:d9:dd:c25:c25:d915:fc55
872c19:dd:d9:dd:c25:c25:d915:fc56/1282c19:dd:d9:dd:c25:c25:d915:fc56
882c19:dd:d9:dd:c25:c25:d915:fc57/1282c19:dd:d9:dd:c25:c25:d915:fc57
892c19:dd:d9:dd:c25:c25:d915:fc58/1282c19:dd:d9:dd:c25:c25:d915:fc58
902c19:dd:d9:dd:c25:c25:d915:fc59/1282c19:dd:d9:dd:c25:c25:d915:fc59
912c19:dd:d9:dd:c25:c25:d915:fc5a/1282c19:dd:d9:dd:c25:c25:d915:fc5a
922c19:dd:d9:dd:c25:c25:d915:fc5b/1282c19:dd:d9:dd:c25:c25:d915:fc5b
932c19:dd:d9:dd:c25:c25:d915:fc5c/1282c19:dd:d9:dd:c25:c25:d915:fc5c
942c19:dd:d9:dd:c25:c25:d915:fc5d/1282c19:dd:d9:dd:c25:c25:d915:fc5d
952c19:dd:d9:dd:c25:c25:d915:fc5e/1282c19:dd:d9:dd:c25:c25:d915:fc5e
962c19:dd:d9:dd:c25:c25:d915:fc5f/1282c19:dd:d9:dd:c25:c25:d915:fc5f
972c19:dd:d9:dd:c25:c25:d915:fc60/1282c19:dd:d9:dd:c25:c25:d915:fc60
982c19:dd:d9:dd:c25:c25:d915:fc61/1282c19:dd:d9:dd:c25:c25:d915:fc61
992c19:dd:d9:dd:c25:c25:d915:fc62/1282c19:dd:d9:dd:c25:c25:d915:fc62
1002c19:dd:d9:dd:c25:c25:d915:fc63/1282c19:dd:d9:dd:c25:c25:d915:fc63
1012c19:dd:d9:dd:c25:c25:d915:fc64/1282c19:dd:d9:dd:c25:c25:d915:fc64
1022c19:dd:d9:dd:c25:c25:d915:fc65/1282c19:dd:d9:dd:c25:c25:d915:fc65
1032c19:dd:d9:dd:c25:c25:d915:fc66/1282c19:dd:d9:dd:c25:c25:d915:fc66
1042c19:dd:d9:dd:c25:c25:d915:fc67/1282c19:dd:d9:dd:c25:c25:d915:fc67
1052c19:dd:d9:dd:c25:c25:d915:fc68/1282c19:dd:d9:dd:c25:c25:d915:fc68
1062c19:dd:d9:dd:c25:c25:d915:fc69/1282c19:dd:d9:dd:c25:c25:d915:fc69
1072c19:dd:d9:dd:c25:c25:d915:fc6a/1282c19:dd:d9:dd:c25:c25:d915:fc6a
1082c19:dd:d9:dd:c25:c25:d915:fc6b/1282c19:dd:d9:dd:c25:c25:d915:fc6b
1092c19:dd:d9:dd:c25:c25:d915:fc6c/1282c19:dd:d9:dd:c25:c25:d915:fc6c
1102c19:dd:d9:dd:c25:c25:d915:fc6d/1282c19:dd:d9:dd:c25:c25:d915:fc6d
1112c19:dd:d9:dd:c25:c25:d915:fc6e/1282c19:dd:d9:dd:c25:c25:d915:fc6e
1122c19:dd:d9:dd:c25:c25:d915:fc6f/1282c19:dd:d9:dd:c25:c25:d915:fc6f
1132c19:dd:d9:dd:c25:c25:d915:fc70/1282c19:dd:d9:dd:c25:c25:d915:fc70
1142c19:dd:d9:dd:c25:c25:d915:fc71/1282c19:dd:d9:dd:c25:c25:d915:fc71
1152c19:dd:d9:dd:c25:c25:d915:fc72/1282c19:dd:d9:dd:c25:c25:d915:fc72
1162c19:dd:d9:dd:c25:c25:d915:fc73/1282c19:dd:d9:dd:c25:c25:d915:fc73
1172c19:dd:d9:dd:c25:c25:d915:fc74/1282c19:dd:d9:dd:c25:c25:d915:fc74
1182c19:dd:d9:dd:c25:c25:d915:fc75/1282c19:dd:d9:dd:c25:c25:d915:fc75
1192c19:dd:d9:dd:c25:c25:d915:fc76/1282c19:dd:d9:dd:c25:c25:d915:fc76
1202c19:dd:d9:dd:c25:c25:d915:fc77/1282c19:dd:d9:dd:c25:c25:d915:fc77
1212c19:dd:d9:dd:c25:c25:d915:fc78/1282c19:dd:d9:dd:c25:c25:d915:fc78
1222c19:dd:d9:dd:c25:c25:d915:fc79/1282c19:dd:d9:dd:c25:c25:d915:fc79
1232c19:dd:d9:dd:c25:c25:d915:fc7a/1282c19:dd:d9:dd:c25:c25:d915:fc7a
1242c19:dd:d9:dd:c25:c25:d915:fc7b/1282c19:dd:d9:dd:c25:c25:d915:fc7b
1252c19:dd:d9:dd:c25:c25:d915:fc7c/1282c19:dd:d9:dd:c25:c25:d915:fc7c
1262c19:dd:d9:dd:c25:c25:d915:fc7d/1282c19:dd:d9:dd:c25:c25:d915:fc7d
1272c19:dd:d9:dd:c25:c25:d915:fc7e/1282c19:dd:d9:dd:c25:c25:d915:fc7e
1282c19:dd:d9:dd:c25:c25:d915:fc7f/1282c19:dd:d9:dd:c25:c25:d915:fc7f
1292c19:dd:d9:dd:c25:c25:d915:fc80/1282c19:dd:d9:dd:c25:c25:d915:fc80
1302c19:dd:d9:dd:c25:c25:d915:fc81/1282c19:dd:d9:dd:c25:c25:d915:fc81
1312c19:dd:d9:dd:c25:c25:d915:fc82/1282c19:dd:d9:dd:c25:c25:d915:fc82
1322c19:dd:d9:dd:c25:c25:d915:fc83/1282c19:dd:d9:dd:c25:c25:d915:fc83
1332c19:dd:d9:dd:c25:c25:d915:fc84/1282c19:dd:d9:dd:c25:c25:d915:fc84
1342c19:dd:d9:dd:c25:c25:d915:fc85/1282c19:dd:d9:dd:c25:c25:d915:fc85
1352c19:dd:d9:dd:c25:c25:d915:fc86/1282c19:dd:d9:dd:c25:c25:d915:fc86
1362c19:dd:d9:dd:c25:c25:d915:fc87/1282c19:dd:d9:dd:c25:c25:d915:fc87
1372c19:dd:d9:dd:c25:c25:d915:fc88/1282c19:dd:d9:dd:c25:c25:d915:fc88
1382c19:dd:d9:dd:c25:c25:d915:fc89/1282c19:dd:d9:dd:c25:c25:d915:fc89
1392c19:dd:d9:dd:c25:c25:d915:fc8a/1282c19:dd:d9:dd:c25:c25:d915:fc8a
1402c19:dd:d9:dd:c25:c25:d915:fc8b/1282c19:dd:d9:dd:c25:c25:d915:fc8b
1412c19:dd:d9:dd:c25:c25:d915:fc8c/1282c19:dd:d9:dd:c25:c25:d915:fc8c
1422c19:dd:d9:dd:c25:c25:d915:fc8d/1282c19:dd:d9:dd:c25:c25:d915:fc8d
1432c19:dd:d9:dd:c25:c25:d915:fc8e/1282c19:dd:d9:dd:c25:c25:d915:fc8e
1442c19:dd:d9:dd:c25:c25:d915:fc8f/1282c19:dd:d9:dd:c25:c25:d915:fc8f
1452c19:dd:d9:dd:c25:c25:d915:fc90/1282c19:dd:d9:dd:c25:c25:d915:fc90
1462c19:dd:d9:dd:c25:c25:d915:fc91/1282c19:dd:d9:dd:c25:c25:d915:fc91
1472c19:dd:d9:dd:c25:c25:d915:fc92/1282c19:dd:d9:dd:c25:c25:d915:fc92
1482c19:dd:d9:dd:c25:c25:d915:fc93/1282c19:dd:d9:dd:c25:c25:d915:fc93
1492c19:dd:d9:dd:c25:c25:d915:fc94/1282c19:dd:d9:dd:c25:c25:d915:fc94
1502c19:dd:d9:dd:c25:c25:d915:fc95/1282c19:dd:d9:dd:c25:c25:d915:fc95
1512c19:dd:d9:dd:c25:c25:d915:fc96/1282c19:dd:d9:dd:c25:c25:d915:fc96
1522c19:dd:d9:dd:c25:c25:d915:fc97/1282c19:dd:d9:dd:c25:c25:d915:fc97
1532c19:dd:d9:dd:c25:c25:d915:fc98/1282c19:dd:d9:dd:c25:c25:d915:fc98
1542c19:dd:d9:dd:c25:c25:d915:fc99/1282c19:dd:d9:dd:c25:c25:d915:fc99
1552c19:dd:d9:dd:c25:c25:d915:fc9a/1282c19:dd:d9:dd:c25:c25:d915:fc9a
1562c19:dd:d9:dd:c25:c25:d915:fc9b/1282c19:dd:d9:dd:c25:c25:d915:fc9b
1572c19:dd:d9:dd:c25:c25:d915:fc9c/1282c19:dd:d9:dd:c25:c25:d915:fc9c
1582c19:dd:d9:dd:c25:c25:d915:fc9d/1282c19:dd:d9:dd:c25:c25:d915:fc9d
1592c19:dd:d9:dd:c25:c25:d915:fc9e/1282c19:dd:d9:dd:c25:c25:d915:fc9e
1602c19:dd:d9:dd:c25:c25:d915:fc9f/1282c19:dd:d9:dd:c25:c25:d915:fc9f
1612c19:dd:d9:dd:c25:c25:d915:fca0/1282c19:dd:d9:dd:c25:c25:d915:fca0
1622c19:dd:d9:dd:c25:c25:d915:fca1/1282c19:dd:d9:dd:c25:c25:d915:fca1
1632c19:dd:d9:dd:c25:c25:d915:fca2/1282c19:dd:d9:dd:c25:c25:d915:fca2
1642c19:dd:d9:dd:c25:c25:d915:fca3/1282c19:dd:d9:dd:c25:c25:d915:fca3
1652c19:dd:d9:dd:c25:c25:d915:fca4/1282c19:dd:d9:dd:c25:c25:d915:fca4
1662c19:dd:d9:dd:c25:c25:d915:fca5/1282c19:dd:d9:dd:c25:c25:d915:fca5
1672c19:dd:d9:dd:c25:c25:d915:fca6/1282c19:dd:d9:dd:c25:c25:d915:fca6
1682c19:dd:d9:dd:c25:c25:d915:fca7/1282c19:dd:d9:dd:c25:c25:d915:fca7
1692c19:dd:d9:dd:c25:c25:d915:fca8/1282c19:dd:d9:dd:c25:c25:d915:fca8
1702c19:dd:d9:dd:c25:c25:d915:fca9/1282c19:dd:d9:dd:c25:c25:d915:fca9
1712c19:dd:d9:dd:c25:c25:d915:fcaa/1282c19:dd:d9:dd:c25:c25:d915:fcaa
1722c19:dd:d9:dd:c25:c25:d915:fcab/1282c19:dd:d9:dd:c25:c25:d915:fcab
1732c19:dd:d9:dd:c25:c25:d915:fcac/1282c19:dd:d9:dd:c25:c25:d915:fcac
1742c19:dd:d9:dd:c25:c25:d915:fcad/1282c19:dd:d9:dd:c25:c25:d915:fcad
1752c19:dd:d9:dd:c25:c25:d915:fcae/1282c19:dd:d9:dd:c25:c25:d915:fcae
1762c19:dd:d9:dd:c25:c25:d915:fcaf/1282c19:dd:d9:dd:c25:c25:d915:fcaf
1772c19:dd:d9:dd:c25:c25:d915:fcb0/1282c19:dd:d9:dd:c25:c25:d915:fcb0
1782c19:dd:d9:dd:c25:c25:d915:fcb1/1282c19:dd:d9:dd:c25:c25:d915:fcb1
1792c19:dd:d9:dd:c25:c25:d915:fcb2/1282c19:dd:d9:dd:c25:c25:d915:fcb2
1802c19:dd:d9:dd:c25:c25:d915:fcb3/1282c19:dd:d9:dd:c25:c25:d915:fcb3
1812c19:dd:d9:dd:c25:c25:d915:fcb4/1282c19:dd:d9:dd:c25:c25:d915:fcb4
1822c19:dd:d9:dd:c25:c25:d915:fcb5/1282c19:dd:d9:dd:c25:c25:d915:fcb5
1832c19:dd:d9:dd:c25:c25:d915:fcb6/1282c19:dd:d9:dd:c25:c25:d915:fcb6
1842c19:dd:d9:dd:c25:c25:d915:fcb7/1282c19:dd:d9:dd:c25:c25:d915:fcb7
1852c19:dd:d9:dd:c25:c25:d915:fcb8/1282c19:dd:d9:dd:c25:c25:d915:fcb8
1862c19:dd:d9:dd:c25:c25:d915:fcb9/1282c19:dd:d9:dd:c25:c25:d915:fcb9
1872c19:dd:d9:dd:c25:c25:d915:fcba/1282c19:dd:d9:dd:c25:c25:d915:fcba
1882c19:dd:d9:dd:c25:c25:d915:fcbb/1282c19:dd:d9:dd:c25:c25:d915:fcbb
1892c19:dd:d9:dd:c25:c25:d915:fcbc/1282c19:dd:d9:dd:c25:c25:d915:fcbc
1902c19:dd:d9:dd:c25:c25:d915:fcbd/1282c19:dd:d9:dd:c25:c25:d915:fcbd
1912c19:dd:d9:dd:c25:c25:d915:fcbe/1282c19:dd:d9:dd:c25:c25:d915:fcbe
1922c19:dd:d9:dd:c25:c25:d915:fcbf/1282c19:dd:d9:dd:c25:c25:d915:fcbf
1932c19:dd:d9:dd:c25:c25:d915:fcc0/1282c19:dd:d9:dd:c25:c25:d915:fcc0
1942c19:dd:d9:dd:c25:c25:d915:fcc1/1282c19:dd:d9:dd:c25:c25:d915:fcc1
1952c19:dd:d9:dd:c25:c25:d915:fcc2/1282c19:dd:d9:dd:c25:c25:d915:fcc2
1962c19:dd:d9:dd:c25:c25:d915:fcc3/1282c19:dd:d9:dd:c25:c25:d915:fcc3
1972c19:dd:d9:dd:c25:c25:d915:fcc4/1282c19:dd:d9:dd:c25:c25:d915:fcc4
1982c19:dd:d9:dd:c25:c25:d915:fcc5/1282c19:dd:d9:dd:c25:c25:d915:fcc5
1992c19:dd:d9:dd:c25:c25:d915:fcc6/1282c19:dd:d9:dd:c25:c25:d915:fcc6
2002c19:dd:d9:dd:c25:c25:d915:fcc7/1282c19:dd:d9:dd:c25:c25:d915:fcc7
2012c19:dd:d9:dd:c25:c25:d915:fcc8/1282c19:dd:d9:dd:c25:c25:d915:fcc8
2022c19:dd:d9:dd:c25:c25:d915:fcc9/1282c19:dd:d9:dd:c25:c25:d915:fcc9
2032c19:dd:d9:dd:c25:c25:d915:fcca/1282c19:dd:d9:dd:c25:c25:d915:fcca
2042c19:dd:d9:dd:c25:c25:d915:fccb/1282c19:dd:d9:dd:c25:c25:d915:fccb
2052c19:dd:d9:dd:c25:c25:d915:fccc/1282c19:dd:d9:dd:c25:c25:d915:fccc
2062c19:dd:d9:dd:c25:c25:d915:fccd/1282c19:dd:d9:dd:c25:c25:d915:fccd
2072c19:dd:d9:dd:c25:c25:d915:fcce/1282c19:dd:d9:dd:c25:c25:d915:fcce
2082c19:dd:d9:dd:c25:c25:d915:fccf/1282c19:dd:d9:dd:c25:c25:d915:fccf
2092c19:dd:d9:dd:c25:c25:d915:fcd0/1282c19:dd:d9:dd:c25:c25:d915:fcd0
2102c19:dd:d9:dd:c25:c25:d915:fcd1/1282c19:dd:d9:dd:c25:c25:d915:fcd1
2112c19:dd:d9:dd:c25:c25:d915:fcd2/1282c19:dd:d9:dd:c25:c25:d915:fcd2
2122c19:dd:d9:dd:c25:c25:d915:fcd3/1282c19:dd:d9:dd:c25:c25:d915:fcd3
2132c19:dd:d9:dd:c25:c25:d915:fcd4/1282c19:dd:d9:dd:c25:c25:d915:fcd4
2142c19:dd:d9:dd:c25:c25:d915:fcd5/1282c19:dd:d9:dd:c25:c25:d915:fcd5
2152c19:dd:d9:dd:c25:c25:d915:fcd6/1282c19:dd:d9:dd:c25:c25:d915:fcd6
2162c19:dd:d9:dd:c25:c25:d915:fcd7/1282c19:dd:d9:dd:c25:c25:d915:fcd7
2172c19:dd:d9:dd:c25:c25:d915:fcd8/1282c19:dd:d9:dd:c25:c25:d915:fcd8
2182c19:dd:d9:dd:c25:c25:d915:fcd9/1282c19:dd:d9:dd:c25:c25:d915:fcd9
2192c19:dd:d9:dd:c25:c25:d915:fcda/1282c19:dd:d9:dd:c25:c25:d915:fcda
2202c19:dd:d9:dd:c25:c25:d915:fcdb/1282c19:dd:d9:dd:c25:c25:d915:fcdb
2212c19:dd:d9:dd:c25:c25:d915:fcdc/1282c19:dd:d9:dd:c25:c25:d915:fcdc
2222c19:dd:d9:dd:c25:c25:d915:fcdd/1282c19:dd:d9:dd:c25:c25:d915:fcdd
2232c19:dd:d9:dd:c25:c25:d915:fcde/1282c19:dd:d9:dd:c25:c25:d915:fcde
2242c19:dd:d9:dd:c25:c25:d915:fcdf/1282c19:dd:d9:dd:c25:c25:d915:fcdf
2252c19:dd:d9:dd:c25:c25:d915:fce0/1282c19:dd:d9:dd:c25:c25:d915:fce0
2262c19:dd:d9:dd:c25:c25:d915:fce1/1282c19:dd:d9:dd:c25:c25:d915:fce1
2272c19:dd:d9:dd:c25:c25:d915:fce2/1282c19:dd:d9:dd:c25:c25:d915:fce2
2282c19:dd:d9:dd:c25:c25:d915:fce3/1282c19:dd:d9:dd:c25:c25:d915:fce3
2292c19:dd:d9:dd:c25:c25:d915:fce4/1282c19:dd:d9:dd:c25:c25:d915:fce4
2302c19:dd:d9:dd:c25:c25:d915:fce5/1282c19:dd:d9:dd:c25:c25:d915:fce5
2312c19:dd:d9:dd:c25:c25:d915:fce6/1282c19:dd:d9:dd:c25:c25:d915:fce6
2322c19:dd:d9:dd:c25:c25:d915:fce7/1282c19:dd:d9:dd:c25:c25:d915:fce7
2332c19:dd:d9:dd:c25:c25:d915:fce8/1282c19:dd:d9:dd:c25:c25:d915:fce8
2342c19:dd:d9:dd:c25:c25:d915:fce9/1282c19:dd:d9:dd:c25:c25:d915:fce9
2352c19:dd:d9:dd:c25:c25:d915:fcea/1282c19:dd:d9:dd:c25:c25:d915:fcea
2362c19:dd:d9:dd:c25:c25:d915:fceb/1282c19:dd:d9:dd:c25:c25:d915:fceb
2372c19:dd:d9:dd:c25:c25:d915:fcec/1282c19:dd:d9:dd:c25:c25:d915:fcec
2382c19:dd:d9:dd:c25:c25:d915:fced/1282c19:dd:d9:dd:c25:c25:d915:fced
2392c19:dd:d9:dd:c25:c25:d915:fcee/1282c19:dd:d9:dd:c25:c25:d915:fcee
2402c19:dd:d9:dd:c25:c25:d915:fcef/1282c19:dd:d9:dd:c25:c25:d915:fcef
2412c19:dd:d9:dd:c25:c25:d915:fcf0/1282c19:dd:d9:dd:c25:c25:d915:fcf0
2422c19:dd:d9:dd:c25:c25:d915:fcf1/1282c19:dd:d9:dd:c25:c25:d915:fcf1
2432c19:dd:d9:dd:c25:c25:d915:fcf2/1282c19:dd:d9:dd:c25:c25:d915:fcf2
2442c19:dd:d9:dd:c25:c25:d915:fcf3/1282c19:dd:d9:dd:c25:c25:d915:fcf3
2452c19:dd:d9:dd:c25:c25:d915:fcf4/1282c19:dd:d9:dd:c25:c25:d915:fcf4
2462c19:dd:d9:dd:c25:c25:d915:fcf5/1282c19:dd:d9:dd:c25:c25:d915:fcf5
2472c19:dd:d9:dd:c25:c25:d915:fcf6/1282c19:dd:d9:dd:c25:c25:d915:fcf6
2482c19:dd:d9:dd:c25:c25:d915:fcf7/1282c19:dd:d9:dd:c25:c25:d915:fcf7
2492c19:dd:d9:dd:c25:c25:d915:fcf8/1282c19:dd:d9:dd:c25:c25:d915:fcf8
2502c19:dd:d9:dd:c25:c25:d915:fcf9/1282c19:dd:d9:dd:c25:c25:d915:fcf9
2512c19:dd:d9:dd:c25:c25:d915:fcfa/1282c19:dd:d9:dd:c25:c25:d915:fcfa
2522c19:dd:d9:dd:c25:c25:d915:fcfb/1282c19:dd:d9:dd:c25:c25:d915:fcfb
2532c19:dd:d9:dd:c25:c25:d915:fcfc/1282c19:dd:d9:dd:c25:c25:d915:fcfc
2542c19:dd:d9:dd:c25:c25:d915:fcfd/1282c19:dd:d9:dd:c25:c25:d915:fcfd
2552c19:dd:d9:dd:c25:c25:d915:fcfe/1282c19:dd:d9:dd:c25:c25:d915:fcfe
2562c19:dd:d9:dd:c25:c25:d915:fcff/1282c19:dd:d9:dd:c25:c25:d915:fcff

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.