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/119
Addresses512
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:94de:ac00/119
First address
2c19:dd:d9:dd:c25:c25:94de:ac00
Last address
2c19:dd:d9:dd:c25:c25:94de:adff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:ac00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
c.a.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
d.a.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
/119 is not on a 4-bit boundary, so it takes 2 /120 zones.
Split into smaller subnets/128
/120 (2)/121 (4)/122 (8)/123 (16)/124 (32)/127 (256)/128 (512)

2c19:dd:d9:dd:c25:c25:94de:ac00/119 makes 512 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:ac00/1282c19:dd:d9:dd:c25:c25:94de:ac00
22c19:dd:d9:dd:c25:c25:94de:ac01/1282c19:dd:d9:dd:c25:c25:94de:ac01
32c19:dd:d9:dd:c25:c25:94de:ac02/1282c19:dd:d9:dd:c25:c25:94de:ac02
42c19:dd:d9:dd:c25:c25:94de:ac03/1282c19:dd:d9:dd:c25:c25:94de:ac03
52c19:dd:d9:dd:c25:c25:94de:ac04/1282c19:dd:d9:dd:c25:c25:94de:ac04
62c19:dd:d9:dd:c25:c25:94de:ac05/1282c19:dd:d9:dd:c25:c25:94de:ac05
72c19:dd:d9:dd:c25:c25:94de:ac06/1282c19:dd:d9:dd:c25:c25:94de:ac06
82c19:dd:d9:dd:c25:c25:94de:ac07/1282c19:dd:d9:dd:c25:c25:94de:ac07
92c19:dd:d9:dd:c25:c25:94de:ac08/1282c19:dd:d9:dd:c25:c25:94de:ac08
102c19:dd:d9:dd:c25:c25:94de:ac09/1282c19:dd:d9:dd:c25:c25:94de:ac09
112c19:dd:d9:dd:c25:c25:94de:ac0a/1282c19:dd:d9:dd:c25:c25:94de:ac0a
122c19:dd:d9:dd:c25:c25:94de:ac0b/1282c19:dd:d9:dd:c25:c25:94de:ac0b
132c19:dd:d9:dd:c25:c25:94de:ac0c/1282c19:dd:d9:dd:c25:c25:94de:ac0c
142c19:dd:d9:dd:c25:c25:94de:ac0d/1282c19:dd:d9:dd:c25:c25:94de:ac0d
152c19:dd:d9:dd:c25:c25:94de:ac0e/1282c19:dd:d9:dd:c25:c25:94de:ac0e
162c19:dd:d9:dd:c25:c25:94de:ac0f/1282c19:dd:d9:dd:c25:c25:94de:ac0f
172c19:dd:d9:dd:c25:c25:94de:ac10/1282c19:dd:d9:dd:c25:c25:94de:ac10
182c19:dd:d9:dd:c25:c25:94de:ac11/1282c19:dd:d9:dd:c25:c25:94de:ac11
192c19:dd:d9:dd:c25:c25:94de:ac12/1282c19:dd:d9:dd:c25:c25:94de:ac12
202c19:dd:d9:dd:c25:c25:94de:ac13/1282c19:dd:d9:dd:c25:c25:94de:ac13
212c19:dd:d9:dd:c25:c25:94de:ac14/1282c19:dd:d9:dd:c25:c25:94de:ac14
222c19:dd:d9:dd:c25:c25:94de:ac15/1282c19:dd:d9:dd:c25:c25:94de:ac15
232c19:dd:d9:dd:c25:c25:94de:ac16/1282c19:dd:d9:dd:c25:c25:94de:ac16
242c19:dd:d9:dd:c25:c25:94de:ac17/1282c19:dd:d9:dd:c25:c25:94de:ac17
252c19:dd:d9:dd:c25:c25:94de:ac18/1282c19:dd:d9:dd:c25:c25:94de:ac18
262c19:dd:d9:dd:c25:c25:94de:ac19/1282c19:dd:d9:dd:c25:c25:94de:ac19
272c19:dd:d9:dd:c25:c25:94de:ac1a/1282c19:dd:d9:dd:c25:c25:94de:ac1a
282c19:dd:d9:dd:c25:c25:94de:ac1b/1282c19:dd:d9:dd:c25:c25:94de:ac1b
292c19:dd:d9:dd:c25:c25:94de:ac1c/1282c19:dd:d9:dd:c25:c25:94de:ac1c
302c19:dd:d9:dd:c25:c25:94de:ac1d/1282c19:dd:d9:dd:c25:c25:94de:ac1d
312c19:dd:d9:dd:c25:c25:94de:ac1e/1282c19:dd:d9:dd:c25:c25:94de:ac1e
322c19:dd:d9:dd:c25:c25:94de:ac1f/1282c19:dd:d9:dd:c25:c25:94de:ac1f
332c19:dd:d9:dd:c25:c25:94de:ac20/1282c19:dd:d9:dd:c25:c25:94de:ac20
342c19:dd:d9:dd:c25:c25:94de:ac21/1282c19:dd:d9:dd:c25:c25:94de:ac21
352c19:dd:d9:dd:c25:c25:94de:ac22/1282c19:dd:d9:dd:c25:c25:94de:ac22
362c19:dd:d9:dd:c25:c25:94de:ac23/1282c19:dd:d9:dd:c25:c25:94de:ac23
372c19:dd:d9:dd:c25:c25:94de:ac24/1282c19:dd:d9:dd:c25:c25:94de:ac24
382c19:dd:d9:dd:c25:c25:94de:ac25/1282c19:dd:d9:dd:c25:c25:94de:ac25
392c19:dd:d9:dd:c25:c25:94de:ac26/1282c19:dd:d9:dd:c25:c25:94de:ac26
402c19:dd:d9:dd:c25:c25:94de:ac27/1282c19:dd:d9:dd:c25:c25:94de:ac27
412c19:dd:d9:dd:c25:c25:94de:ac28/1282c19:dd:d9:dd:c25:c25:94de:ac28
422c19:dd:d9:dd:c25:c25:94de:ac29/1282c19:dd:d9:dd:c25:c25:94de:ac29
432c19:dd:d9:dd:c25:c25:94de:ac2a/1282c19:dd:d9:dd:c25:c25:94de:ac2a
442c19:dd:d9:dd:c25:c25:94de:ac2b/1282c19:dd:d9:dd:c25:c25:94de:ac2b
452c19:dd:d9:dd:c25:c25:94de:ac2c/1282c19:dd:d9:dd:c25:c25:94de:ac2c
462c19:dd:d9:dd:c25:c25:94de:ac2d/1282c19:dd:d9:dd:c25:c25:94de:ac2d
472c19:dd:d9:dd:c25:c25:94de:ac2e/1282c19:dd:d9:dd:c25:c25:94de:ac2e
482c19:dd:d9:dd:c25:c25:94de:ac2f/1282c19:dd:d9:dd:c25:c25:94de:ac2f
492c19:dd:d9:dd:c25:c25:94de:ac30/1282c19:dd:d9:dd:c25:c25:94de:ac30
502c19:dd:d9:dd:c25:c25:94de:ac31/1282c19:dd:d9:dd:c25:c25:94de:ac31
512c19:dd:d9:dd:c25:c25:94de:ac32/1282c19:dd:d9:dd:c25:c25:94de:ac32
522c19:dd:d9:dd:c25:c25:94de:ac33/1282c19:dd:d9:dd:c25:c25:94de:ac33
532c19:dd:d9:dd:c25:c25:94de:ac34/1282c19:dd:d9:dd:c25:c25:94de:ac34
542c19:dd:d9:dd:c25:c25:94de:ac35/1282c19:dd:d9:dd:c25:c25:94de:ac35
552c19:dd:d9:dd:c25:c25:94de:ac36/1282c19:dd:d9:dd:c25:c25:94de:ac36
562c19:dd:d9:dd:c25:c25:94de:ac37/1282c19:dd:d9:dd:c25:c25:94de:ac37
572c19:dd:d9:dd:c25:c25:94de:ac38/1282c19:dd:d9:dd:c25:c25:94de:ac38
582c19:dd:d9:dd:c25:c25:94de:ac39/1282c19:dd:d9:dd:c25:c25:94de:ac39
592c19:dd:d9:dd:c25:c25:94de:ac3a/1282c19:dd:d9:dd:c25:c25:94de:ac3a
602c19:dd:d9:dd:c25:c25:94de:ac3b/1282c19:dd:d9:dd:c25:c25:94de:ac3b
612c19:dd:d9:dd:c25:c25:94de:ac3c/1282c19:dd:d9:dd:c25:c25:94de:ac3c
622c19:dd:d9:dd:c25:c25:94de:ac3d/1282c19:dd:d9:dd:c25:c25:94de:ac3d
632c19:dd:d9:dd:c25:c25:94de:ac3e/1282c19:dd:d9:dd:c25:c25:94de:ac3e
642c19:dd:d9:dd:c25:c25:94de:ac3f/1282c19:dd:d9:dd:c25:c25:94de:ac3f
652c19:dd:d9:dd:c25:c25:94de:ac40/1282c19:dd:d9:dd:c25:c25:94de:ac40
662c19:dd:d9:dd:c25:c25:94de:ac41/1282c19:dd:d9:dd:c25:c25:94de:ac41
672c19:dd:d9:dd:c25:c25:94de:ac42/1282c19:dd:d9:dd:c25:c25:94de:ac42
682c19:dd:d9:dd:c25:c25:94de:ac43/1282c19:dd:d9:dd:c25:c25:94de:ac43
692c19:dd:d9:dd:c25:c25:94de:ac44/1282c19:dd:d9:dd:c25:c25:94de:ac44
702c19:dd:d9:dd:c25:c25:94de:ac45/1282c19:dd:d9:dd:c25:c25:94de:ac45
712c19:dd:d9:dd:c25:c25:94de:ac46/1282c19:dd:d9:dd:c25:c25:94de:ac46
722c19:dd:d9:dd:c25:c25:94de:ac47/1282c19:dd:d9:dd:c25:c25:94de:ac47
732c19:dd:d9:dd:c25:c25:94de:ac48/1282c19:dd:d9:dd:c25:c25:94de:ac48
742c19:dd:d9:dd:c25:c25:94de:ac49/1282c19:dd:d9:dd:c25:c25:94de:ac49
752c19:dd:d9:dd:c25:c25:94de:ac4a/1282c19:dd:d9:dd:c25:c25:94de:ac4a
762c19:dd:d9:dd:c25:c25:94de:ac4b/1282c19:dd:d9:dd:c25:c25:94de:ac4b
772c19:dd:d9:dd:c25:c25:94de:ac4c/1282c19:dd:d9:dd:c25:c25:94de:ac4c
782c19:dd:d9:dd:c25:c25:94de:ac4d/1282c19:dd:d9:dd:c25:c25:94de:ac4d
792c19:dd:d9:dd:c25:c25:94de:ac4e/1282c19:dd:d9:dd:c25:c25:94de:ac4e
802c19:dd:d9:dd:c25:c25:94de:ac4f/1282c19:dd:d9:dd:c25:c25:94de:ac4f
812c19:dd:d9:dd:c25:c25:94de:ac50/1282c19:dd:d9:dd:c25:c25:94de:ac50
822c19:dd:d9:dd:c25:c25:94de:ac51/1282c19:dd:d9:dd:c25:c25:94de:ac51
832c19:dd:d9:dd:c25:c25:94de:ac52/1282c19:dd:d9:dd:c25:c25:94de:ac52
842c19:dd:d9:dd:c25:c25:94de:ac53/1282c19:dd:d9:dd:c25:c25:94de:ac53
852c19:dd:d9:dd:c25:c25:94de:ac54/1282c19:dd:d9:dd:c25:c25:94de:ac54
862c19:dd:d9:dd:c25:c25:94de:ac55/1282c19:dd:d9:dd:c25:c25:94de:ac55
872c19:dd:d9:dd:c25:c25:94de:ac56/1282c19:dd:d9:dd:c25:c25:94de:ac56
882c19:dd:d9:dd:c25:c25:94de:ac57/1282c19:dd:d9:dd:c25:c25:94de:ac57
892c19:dd:d9:dd:c25:c25:94de:ac58/1282c19:dd:d9:dd:c25:c25:94de:ac58
902c19:dd:d9:dd:c25:c25:94de:ac59/1282c19:dd:d9:dd:c25:c25:94de:ac59
912c19:dd:d9:dd:c25:c25:94de:ac5a/1282c19:dd:d9:dd:c25:c25:94de:ac5a
922c19:dd:d9:dd:c25:c25:94de:ac5b/1282c19:dd:d9:dd:c25:c25:94de:ac5b
932c19:dd:d9:dd:c25:c25:94de:ac5c/1282c19:dd:d9:dd:c25:c25:94de:ac5c
942c19:dd:d9:dd:c25:c25:94de:ac5d/1282c19:dd:d9:dd:c25:c25:94de:ac5d
952c19:dd:d9:dd:c25:c25:94de:ac5e/1282c19:dd:d9:dd:c25:c25:94de:ac5e
962c19:dd:d9:dd:c25:c25:94de:ac5f/1282c19:dd:d9:dd:c25:c25:94de:ac5f
972c19:dd:d9:dd:c25:c25:94de:ac60/1282c19:dd:d9:dd:c25:c25:94de:ac60
982c19:dd:d9:dd:c25:c25:94de:ac61/1282c19:dd:d9:dd:c25:c25:94de:ac61
992c19:dd:d9:dd:c25:c25:94de:ac62/1282c19:dd:d9:dd:c25:c25:94de:ac62
1002c19:dd:d9:dd:c25:c25:94de:ac63/1282c19:dd:d9:dd:c25:c25:94de:ac63
1012c19:dd:d9:dd:c25:c25:94de:ac64/1282c19:dd:d9:dd:c25:c25:94de:ac64
1022c19:dd:d9:dd:c25:c25:94de:ac65/1282c19:dd:d9:dd:c25:c25:94de:ac65
1032c19:dd:d9:dd:c25:c25:94de:ac66/1282c19:dd:d9:dd:c25:c25:94de:ac66
1042c19:dd:d9:dd:c25:c25:94de:ac67/1282c19:dd:d9:dd:c25:c25:94de:ac67
1052c19:dd:d9:dd:c25:c25:94de:ac68/1282c19:dd:d9:dd:c25:c25:94de:ac68
1062c19:dd:d9:dd:c25:c25:94de:ac69/1282c19:dd:d9:dd:c25:c25:94de:ac69
1072c19:dd:d9:dd:c25:c25:94de:ac6a/1282c19:dd:d9:dd:c25:c25:94de:ac6a
1082c19:dd:d9:dd:c25:c25:94de:ac6b/1282c19:dd:d9:dd:c25:c25:94de:ac6b
1092c19:dd:d9:dd:c25:c25:94de:ac6c/1282c19:dd:d9:dd:c25:c25:94de:ac6c
1102c19:dd:d9:dd:c25:c25:94de:ac6d/1282c19:dd:d9:dd:c25:c25:94de:ac6d
1112c19:dd:d9:dd:c25:c25:94de:ac6e/1282c19:dd:d9:dd:c25:c25:94de:ac6e
1122c19:dd:d9:dd:c25:c25:94de:ac6f/1282c19:dd:d9:dd:c25:c25:94de:ac6f
1132c19:dd:d9:dd:c25:c25:94de:ac70/1282c19:dd:d9:dd:c25:c25:94de:ac70
1142c19:dd:d9:dd:c25:c25:94de:ac71/1282c19:dd:d9:dd:c25:c25:94de:ac71
1152c19:dd:d9:dd:c25:c25:94de:ac72/1282c19:dd:d9:dd:c25:c25:94de:ac72
1162c19:dd:d9:dd:c25:c25:94de:ac73/1282c19:dd:d9:dd:c25:c25:94de:ac73
1172c19:dd:d9:dd:c25:c25:94de:ac74/1282c19:dd:d9:dd:c25:c25:94de:ac74
1182c19:dd:d9:dd:c25:c25:94de:ac75/1282c19:dd:d9:dd:c25:c25:94de:ac75
1192c19:dd:d9:dd:c25:c25:94de:ac76/1282c19:dd:d9:dd:c25:c25:94de:ac76
1202c19:dd:d9:dd:c25:c25:94de:ac77/1282c19:dd:d9:dd:c25:c25:94de:ac77
1212c19:dd:d9:dd:c25:c25:94de:ac78/1282c19:dd:d9:dd:c25:c25:94de:ac78
1222c19:dd:d9:dd:c25:c25:94de:ac79/1282c19:dd:d9:dd:c25:c25:94de:ac79
1232c19:dd:d9:dd:c25:c25:94de:ac7a/1282c19:dd:d9:dd:c25:c25:94de:ac7a
1242c19:dd:d9:dd:c25:c25:94de:ac7b/1282c19:dd:d9:dd:c25:c25:94de:ac7b
1252c19:dd:d9:dd:c25:c25:94de:ac7c/1282c19:dd:d9:dd:c25:c25:94de:ac7c
1262c19:dd:d9:dd:c25:c25:94de:ac7d/1282c19:dd:d9:dd:c25:c25:94de:ac7d
1272c19:dd:d9:dd:c25:c25:94de:ac7e/1282c19:dd:d9:dd:c25:c25:94de:ac7e
1282c19:dd:d9:dd:c25:c25:94de:ac7f/1282c19:dd:d9:dd:c25:c25:94de:ac7f
1292c19:dd:d9:dd:c25:c25:94de:ac80/1282c19:dd:d9:dd:c25:c25:94de:ac80
1302c19:dd:d9:dd:c25:c25:94de:ac81/1282c19:dd:d9:dd:c25:c25:94de:ac81
1312c19:dd:d9:dd:c25:c25:94de:ac82/1282c19:dd:d9:dd:c25:c25:94de:ac82
1322c19:dd:d9:dd:c25:c25:94de:ac83/1282c19:dd:d9:dd:c25:c25:94de:ac83
1332c19:dd:d9:dd:c25:c25:94de:ac84/1282c19:dd:d9:dd:c25:c25:94de:ac84
1342c19:dd:d9:dd:c25:c25:94de:ac85/1282c19:dd:d9:dd:c25:c25:94de:ac85
1352c19:dd:d9:dd:c25:c25:94de:ac86/1282c19:dd:d9:dd:c25:c25:94de:ac86
1362c19:dd:d9:dd:c25:c25:94de:ac87/1282c19:dd:d9:dd:c25:c25:94de:ac87
1372c19:dd:d9:dd:c25:c25:94de:ac88/1282c19:dd:d9:dd:c25:c25:94de:ac88
1382c19:dd:d9:dd:c25:c25:94de:ac89/1282c19:dd:d9:dd:c25:c25:94de:ac89
1392c19:dd:d9:dd:c25:c25:94de:ac8a/1282c19:dd:d9:dd:c25:c25:94de:ac8a
1402c19:dd:d9:dd:c25:c25:94de:ac8b/1282c19:dd:d9:dd:c25:c25:94de:ac8b
1412c19:dd:d9:dd:c25:c25:94de:ac8c/1282c19:dd:d9:dd:c25:c25:94de:ac8c
1422c19:dd:d9:dd:c25:c25:94de:ac8d/1282c19:dd:d9:dd:c25:c25:94de:ac8d
1432c19:dd:d9:dd:c25:c25:94de:ac8e/1282c19:dd:d9:dd:c25:c25:94de:ac8e
1442c19:dd:d9:dd:c25:c25:94de:ac8f/1282c19:dd:d9:dd:c25:c25:94de:ac8f
1452c19:dd:d9:dd:c25:c25:94de:ac90/1282c19:dd:d9:dd:c25:c25:94de:ac90
1462c19:dd:d9:dd:c25:c25:94de:ac91/1282c19:dd:d9:dd:c25:c25:94de:ac91
1472c19:dd:d9:dd:c25:c25:94de:ac92/1282c19:dd:d9:dd:c25:c25:94de:ac92
1482c19:dd:d9:dd:c25:c25:94de:ac93/1282c19:dd:d9:dd:c25:c25:94de:ac93
1492c19:dd:d9:dd:c25:c25:94de:ac94/1282c19:dd:d9:dd:c25:c25:94de:ac94
1502c19:dd:d9:dd:c25:c25:94de:ac95/1282c19:dd:d9:dd:c25:c25:94de:ac95
1512c19:dd:d9:dd:c25:c25:94de:ac96/1282c19:dd:d9:dd:c25:c25:94de:ac96
1522c19:dd:d9:dd:c25:c25:94de:ac97/1282c19:dd:d9:dd:c25:c25:94de:ac97
1532c19:dd:d9:dd:c25:c25:94de:ac98/1282c19:dd:d9:dd:c25:c25:94de:ac98
1542c19:dd:d9:dd:c25:c25:94de:ac99/1282c19:dd:d9:dd:c25:c25:94de:ac99
1552c19:dd:d9:dd:c25:c25:94de:ac9a/1282c19:dd:d9:dd:c25:c25:94de:ac9a
1562c19:dd:d9:dd:c25:c25:94de:ac9b/1282c19:dd:d9:dd:c25:c25:94de:ac9b
1572c19:dd:d9:dd:c25:c25:94de:ac9c/1282c19:dd:d9:dd:c25:c25:94de:ac9c
1582c19:dd:d9:dd:c25:c25:94de:ac9d/1282c19:dd:d9:dd:c25:c25:94de:ac9d
1592c19:dd:d9:dd:c25:c25:94de:ac9e/1282c19:dd:d9:dd:c25:c25:94de:ac9e
1602c19:dd:d9:dd:c25:c25:94de:ac9f/1282c19:dd:d9:dd:c25:c25:94de:ac9f
1612c19:dd:d9:dd:c25:c25:94de:aca0/1282c19:dd:d9:dd:c25:c25:94de:aca0
1622c19:dd:d9:dd:c25:c25:94de:aca1/1282c19:dd:d9:dd:c25:c25:94de:aca1
1632c19:dd:d9:dd:c25:c25:94de:aca2/1282c19:dd:d9:dd:c25:c25:94de:aca2
1642c19:dd:d9:dd:c25:c25:94de:aca3/1282c19:dd:d9:dd:c25:c25:94de:aca3
1652c19:dd:d9:dd:c25:c25:94de:aca4/1282c19:dd:d9:dd:c25:c25:94de:aca4
1662c19:dd:d9:dd:c25:c25:94de:aca5/1282c19:dd:d9:dd:c25:c25:94de:aca5
1672c19:dd:d9:dd:c25:c25:94de:aca6/1282c19:dd:d9:dd:c25:c25:94de:aca6
1682c19:dd:d9:dd:c25:c25:94de:aca7/1282c19:dd:d9:dd:c25:c25:94de:aca7
1692c19:dd:d9:dd:c25:c25:94de:aca8/1282c19:dd:d9:dd:c25:c25:94de:aca8
1702c19:dd:d9:dd:c25:c25:94de:aca9/1282c19:dd:d9:dd:c25:c25:94de:aca9
1712c19:dd:d9:dd:c25:c25:94de:acaa/1282c19:dd:d9:dd:c25:c25:94de:acaa
1722c19:dd:d9:dd:c25:c25:94de:acab/1282c19:dd:d9:dd:c25:c25:94de:acab
1732c19:dd:d9:dd:c25:c25:94de:acac/1282c19:dd:d9:dd:c25:c25:94de:acac
1742c19:dd:d9:dd:c25:c25:94de:acad/1282c19:dd:d9:dd:c25:c25:94de:acad
1752c19:dd:d9:dd:c25:c25:94de:acae/1282c19:dd:d9:dd:c25:c25:94de:acae
1762c19:dd:d9:dd:c25:c25:94de:acaf/1282c19:dd:d9:dd:c25:c25:94de:acaf
1772c19:dd:d9:dd:c25:c25:94de:acb0/1282c19:dd:d9:dd:c25:c25:94de:acb0
1782c19:dd:d9:dd:c25:c25:94de:acb1/1282c19:dd:d9:dd:c25:c25:94de:acb1
1792c19:dd:d9:dd:c25:c25:94de:acb2/1282c19:dd:d9:dd:c25:c25:94de:acb2
1802c19:dd:d9:dd:c25:c25:94de:acb3/1282c19:dd:d9:dd:c25:c25:94de:acb3
1812c19:dd:d9:dd:c25:c25:94de:acb4/1282c19:dd:d9:dd:c25:c25:94de:acb4
1822c19:dd:d9:dd:c25:c25:94de:acb5/1282c19:dd:d9:dd:c25:c25:94de:acb5
1832c19:dd:d9:dd:c25:c25:94de:acb6/1282c19:dd:d9:dd:c25:c25:94de:acb6
1842c19:dd:d9:dd:c25:c25:94de:acb7/1282c19:dd:d9:dd:c25:c25:94de:acb7
1852c19:dd:d9:dd:c25:c25:94de:acb8/1282c19:dd:d9:dd:c25:c25:94de:acb8
1862c19:dd:d9:dd:c25:c25:94de:acb9/1282c19:dd:d9:dd:c25:c25:94de:acb9
1872c19:dd:d9:dd:c25:c25:94de:acba/1282c19:dd:d9:dd:c25:c25:94de:acba
1882c19:dd:d9:dd:c25:c25:94de:acbb/1282c19:dd:d9:dd:c25:c25:94de:acbb
1892c19:dd:d9:dd:c25:c25:94de:acbc/1282c19:dd:d9:dd:c25:c25:94de:acbc
1902c19:dd:d9:dd:c25:c25:94de:acbd/1282c19:dd:d9:dd:c25:c25:94de:acbd
1912c19:dd:d9:dd:c25:c25:94de:acbe/1282c19:dd:d9:dd:c25:c25:94de:acbe
1922c19:dd:d9:dd:c25:c25:94de:acbf/1282c19:dd:d9:dd:c25:c25:94de:acbf
1932c19:dd:d9:dd:c25:c25:94de:acc0/1282c19:dd:d9:dd:c25:c25:94de:acc0
1942c19:dd:d9:dd:c25:c25:94de:acc1/1282c19:dd:d9:dd:c25:c25:94de:acc1
1952c19:dd:d9:dd:c25:c25:94de:acc2/1282c19:dd:d9:dd:c25:c25:94de:acc2
1962c19:dd:d9:dd:c25:c25:94de:acc3/1282c19:dd:d9:dd:c25:c25:94de:acc3
1972c19:dd:d9:dd:c25:c25:94de:acc4/1282c19:dd:d9:dd:c25:c25:94de:acc4
1982c19:dd:d9:dd:c25:c25:94de:acc5/1282c19:dd:d9:dd:c25:c25:94de:acc5
1992c19:dd:d9:dd:c25:c25:94de:acc6/1282c19:dd:d9:dd:c25:c25:94de:acc6
2002c19:dd:d9:dd:c25:c25:94de:acc7/1282c19:dd:d9:dd:c25:c25:94de:acc7
2012c19:dd:d9:dd:c25:c25:94de:acc8/1282c19:dd:d9:dd:c25:c25:94de:acc8
2022c19:dd:d9:dd:c25:c25:94de:acc9/1282c19:dd:d9:dd:c25:c25:94de:acc9
2032c19:dd:d9:dd:c25:c25:94de:acca/1282c19:dd:d9:dd:c25:c25:94de:acca
2042c19:dd:d9:dd:c25:c25:94de:accb/1282c19:dd:d9:dd:c25:c25:94de:accb
2052c19:dd:d9:dd:c25:c25:94de:accc/1282c19:dd:d9:dd:c25:c25:94de:accc
2062c19:dd:d9:dd:c25:c25:94de:accd/1282c19:dd:d9:dd:c25:c25:94de:accd
2072c19:dd:d9:dd:c25:c25:94de:acce/1282c19:dd:d9:dd:c25:c25:94de:acce
2082c19:dd:d9:dd:c25:c25:94de:accf/1282c19:dd:d9:dd:c25:c25:94de:accf
2092c19:dd:d9:dd:c25:c25:94de:acd0/1282c19:dd:d9:dd:c25:c25:94de:acd0
2102c19:dd:d9:dd:c25:c25:94de:acd1/1282c19:dd:d9:dd:c25:c25:94de:acd1
2112c19:dd:d9:dd:c25:c25:94de:acd2/1282c19:dd:d9:dd:c25:c25:94de:acd2
2122c19:dd:d9:dd:c25:c25:94de:acd3/1282c19:dd:d9:dd:c25:c25:94de:acd3
2132c19:dd:d9:dd:c25:c25:94de:acd4/1282c19:dd:d9:dd:c25:c25:94de:acd4
2142c19:dd:d9:dd:c25:c25:94de:acd5/1282c19:dd:d9:dd:c25:c25:94de:acd5
2152c19:dd:d9:dd:c25:c25:94de:acd6/1282c19:dd:d9:dd:c25:c25:94de:acd6
2162c19:dd:d9:dd:c25:c25:94de:acd7/1282c19:dd:d9:dd:c25:c25:94de:acd7
2172c19:dd:d9:dd:c25:c25:94de:acd8/1282c19:dd:d9:dd:c25:c25:94de:acd8
2182c19:dd:d9:dd:c25:c25:94de:acd9/1282c19:dd:d9:dd:c25:c25:94de:acd9
2192c19:dd:d9:dd:c25:c25:94de:acda/1282c19:dd:d9:dd:c25:c25:94de:acda
2202c19:dd:d9:dd:c25:c25:94de:acdb/1282c19:dd:d9:dd:c25:c25:94de:acdb
2212c19:dd:d9:dd:c25:c25:94de:acdc/1282c19:dd:d9:dd:c25:c25:94de:acdc
2222c19:dd:d9:dd:c25:c25:94de:acdd/1282c19:dd:d9:dd:c25:c25:94de:acdd
2232c19:dd:d9:dd:c25:c25:94de:acde/1282c19:dd:d9:dd:c25:c25:94de:acde
2242c19:dd:d9:dd:c25:c25:94de:acdf/1282c19:dd:d9:dd:c25:c25:94de:acdf
2252c19:dd:d9:dd:c25:c25:94de:ace0/1282c19:dd:d9:dd:c25:c25:94de:ace0
2262c19:dd:d9:dd:c25:c25:94de:ace1/1282c19:dd:d9:dd:c25:c25:94de:ace1
2272c19:dd:d9:dd:c25:c25:94de:ace2/1282c19:dd:d9:dd:c25:c25:94de:ace2
2282c19:dd:d9:dd:c25:c25:94de:ace3/1282c19:dd:d9:dd:c25:c25:94de:ace3
2292c19:dd:d9:dd:c25:c25:94de:ace4/1282c19:dd:d9:dd:c25:c25:94de:ace4
2302c19:dd:d9:dd:c25:c25:94de:ace5/1282c19:dd:d9:dd:c25:c25:94de:ace5
2312c19:dd:d9:dd:c25:c25:94de:ace6/1282c19:dd:d9:dd:c25:c25:94de:ace6
2322c19:dd:d9:dd:c25:c25:94de:ace7/1282c19:dd:d9:dd:c25:c25:94de:ace7
2332c19:dd:d9:dd:c25:c25:94de:ace8/1282c19:dd:d9:dd:c25:c25:94de:ace8
2342c19:dd:d9:dd:c25:c25:94de:ace9/1282c19:dd:d9:dd:c25:c25:94de:ace9
2352c19:dd:d9:dd:c25:c25:94de:acea/1282c19:dd:d9:dd:c25:c25:94de:acea
2362c19:dd:d9:dd:c25:c25:94de:aceb/1282c19:dd:d9:dd:c25:c25:94de:aceb
2372c19:dd:d9:dd:c25:c25:94de:acec/1282c19:dd:d9:dd:c25:c25:94de:acec
2382c19:dd:d9:dd:c25:c25:94de:aced/1282c19:dd:d9:dd:c25:c25:94de:aced
2392c19:dd:d9:dd:c25:c25:94de:acee/1282c19:dd:d9:dd:c25:c25:94de:acee
2402c19:dd:d9:dd:c25:c25:94de:acef/1282c19:dd:d9:dd:c25:c25:94de:acef
2412c19:dd:d9:dd:c25:c25:94de:acf0/1282c19:dd:d9:dd:c25:c25:94de:acf0
2422c19:dd:d9:dd:c25:c25:94de:acf1/1282c19:dd:d9:dd:c25:c25:94de:acf1
2432c19:dd:d9:dd:c25:c25:94de:acf2/1282c19:dd:d9:dd:c25:c25:94de:acf2
2442c19:dd:d9:dd:c25:c25:94de:acf3/1282c19:dd:d9:dd:c25:c25:94de:acf3
2452c19:dd:d9:dd:c25:c25:94de:acf4/1282c19:dd:d9:dd:c25:c25:94de:acf4
2462c19:dd:d9:dd:c25:c25:94de:acf5/1282c19:dd:d9:dd:c25:c25:94de:acf5
2472c19:dd:d9:dd:c25:c25:94de:acf6/1282c19:dd:d9:dd:c25:c25:94de:acf6
2482c19:dd:d9:dd:c25:c25:94de:acf7/1282c19:dd:d9:dd:c25:c25:94de:acf7
2492c19:dd:d9:dd:c25:c25:94de:acf8/1282c19:dd:d9:dd:c25:c25:94de:acf8
2502c19:dd:d9:dd:c25:c25:94de:acf9/1282c19:dd:d9:dd:c25:c25:94de:acf9
2512c19:dd:d9:dd:c25:c25:94de:acfa/1282c19:dd:d9:dd:c25:c25:94de:acfa
2522c19:dd:d9:dd:c25:c25:94de:acfb/1282c19:dd:d9:dd:c25:c25:94de:acfb
2532c19:dd:d9:dd:c25:c25:94de:acfc/1282c19:dd:d9:dd:c25:c25:94de:acfc
2542c19:dd:d9:dd:c25:c25:94de:acfd/1282c19:dd:d9:dd:c25:c25:94de:acfd
2552c19:dd:d9:dd:c25:c25:94de:acfe/1282c19:dd:d9:dd:c25:c25:94de:acfe
2562c19:dd:d9:dd:c25:c25:94de:acff/1282c19:dd:d9:dd:c25:c25:94de:acff

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.