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:bf00/120
First address
2c19:dd:d9:dd:c25:c25:94de:bf00
Last address
2c19:dd:d9:dd:c25:c25:94de:bfff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:bf00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
f.b.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:bf00/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:bf00/1282c19:dd:d9:dd:c25:c25:94de:bf00
22c19:dd:d9:dd:c25:c25:94de:bf01/1282c19:dd:d9:dd:c25:c25:94de:bf01
32c19:dd:d9:dd:c25:c25:94de:bf02/1282c19:dd:d9:dd:c25:c25:94de:bf02
42c19:dd:d9:dd:c25:c25:94de:bf03/1282c19:dd:d9:dd:c25:c25:94de:bf03
52c19:dd:d9:dd:c25:c25:94de:bf04/1282c19:dd:d9:dd:c25:c25:94de:bf04
62c19:dd:d9:dd:c25:c25:94de:bf05/1282c19:dd:d9:dd:c25:c25:94de:bf05
72c19:dd:d9:dd:c25:c25:94de:bf06/1282c19:dd:d9:dd:c25:c25:94de:bf06
82c19:dd:d9:dd:c25:c25:94de:bf07/1282c19:dd:d9:dd:c25:c25:94de:bf07
92c19:dd:d9:dd:c25:c25:94de:bf08/1282c19:dd:d9:dd:c25:c25:94de:bf08
102c19:dd:d9:dd:c25:c25:94de:bf09/1282c19:dd:d9:dd:c25:c25:94de:bf09
112c19:dd:d9:dd:c25:c25:94de:bf0a/1282c19:dd:d9:dd:c25:c25:94de:bf0a
122c19:dd:d9:dd:c25:c25:94de:bf0b/1282c19:dd:d9:dd:c25:c25:94de:bf0b
132c19:dd:d9:dd:c25:c25:94de:bf0c/1282c19:dd:d9:dd:c25:c25:94de:bf0c
142c19:dd:d9:dd:c25:c25:94de:bf0d/1282c19:dd:d9:dd:c25:c25:94de:bf0d
152c19:dd:d9:dd:c25:c25:94de:bf0e/1282c19:dd:d9:dd:c25:c25:94de:bf0e
162c19:dd:d9:dd:c25:c25:94de:bf0f/1282c19:dd:d9:dd:c25:c25:94de:bf0f
172c19:dd:d9:dd:c25:c25:94de:bf10/1282c19:dd:d9:dd:c25:c25:94de:bf10
182c19:dd:d9:dd:c25:c25:94de:bf11/1282c19:dd:d9:dd:c25:c25:94de:bf11
192c19:dd:d9:dd:c25:c25:94de:bf12/1282c19:dd:d9:dd:c25:c25:94de:bf12
202c19:dd:d9:dd:c25:c25:94de:bf13/1282c19:dd:d9:dd:c25:c25:94de:bf13
212c19:dd:d9:dd:c25:c25:94de:bf14/1282c19:dd:d9:dd:c25:c25:94de:bf14
222c19:dd:d9:dd:c25:c25:94de:bf15/1282c19:dd:d9:dd:c25:c25:94de:bf15
232c19:dd:d9:dd:c25:c25:94de:bf16/1282c19:dd:d9:dd:c25:c25:94de:bf16
242c19:dd:d9:dd:c25:c25:94de:bf17/1282c19:dd:d9:dd:c25:c25:94de:bf17
252c19:dd:d9:dd:c25:c25:94de:bf18/1282c19:dd:d9:dd:c25:c25:94de:bf18
262c19:dd:d9:dd:c25:c25:94de:bf19/1282c19:dd:d9:dd:c25:c25:94de:bf19
272c19:dd:d9:dd:c25:c25:94de:bf1a/1282c19:dd:d9:dd:c25:c25:94de:bf1a
282c19:dd:d9:dd:c25:c25:94de:bf1b/1282c19:dd:d9:dd:c25:c25:94de:bf1b
292c19:dd:d9:dd:c25:c25:94de:bf1c/1282c19:dd:d9:dd:c25:c25:94de:bf1c
302c19:dd:d9:dd:c25:c25:94de:bf1d/1282c19:dd:d9:dd:c25:c25:94de:bf1d
312c19:dd:d9:dd:c25:c25:94de:bf1e/1282c19:dd:d9:dd:c25:c25:94de:bf1e
322c19:dd:d9:dd:c25:c25:94de:bf1f/1282c19:dd:d9:dd:c25:c25:94de:bf1f
332c19:dd:d9:dd:c25:c25:94de:bf20/1282c19:dd:d9:dd:c25:c25:94de:bf20
342c19:dd:d9:dd:c25:c25:94de:bf21/1282c19:dd:d9:dd:c25:c25:94de:bf21
352c19:dd:d9:dd:c25:c25:94de:bf22/1282c19:dd:d9:dd:c25:c25:94de:bf22
362c19:dd:d9:dd:c25:c25:94de:bf23/1282c19:dd:d9:dd:c25:c25:94de:bf23
372c19:dd:d9:dd:c25:c25:94de:bf24/1282c19:dd:d9:dd:c25:c25:94de:bf24
382c19:dd:d9:dd:c25:c25:94de:bf25/1282c19:dd:d9:dd:c25:c25:94de:bf25
392c19:dd:d9:dd:c25:c25:94de:bf26/1282c19:dd:d9:dd:c25:c25:94de:bf26
402c19:dd:d9:dd:c25:c25:94de:bf27/1282c19:dd:d9:dd:c25:c25:94de:bf27
412c19:dd:d9:dd:c25:c25:94de:bf28/1282c19:dd:d9:dd:c25:c25:94de:bf28
422c19:dd:d9:dd:c25:c25:94de:bf29/1282c19:dd:d9:dd:c25:c25:94de:bf29
432c19:dd:d9:dd:c25:c25:94de:bf2a/1282c19:dd:d9:dd:c25:c25:94de:bf2a
442c19:dd:d9:dd:c25:c25:94de:bf2b/1282c19:dd:d9:dd:c25:c25:94de:bf2b
452c19:dd:d9:dd:c25:c25:94de:bf2c/1282c19:dd:d9:dd:c25:c25:94de:bf2c
462c19:dd:d9:dd:c25:c25:94de:bf2d/1282c19:dd:d9:dd:c25:c25:94de:bf2d
472c19:dd:d9:dd:c25:c25:94de:bf2e/1282c19:dd:d9:dd:c25:c25:94de:bf2e
482c19:dd:d9:dd:c25:c25:94de:bf2f/1282c19:dd:d9:dd:c25:c25:94de:bf2f
492c19:dd:d9:dd:c25:c25:94de:bf30/1282c19:dd:d9:dd:c25:c25:94de:bf30
502c19:dd:d9:dd:c25:c25:94de:bf31/1282c19:dd:d9:dd:c25:c25:94de:bf31
512c19:dd:d9:dd:c25:c25:94de:bf32/1282c19:dd:d9:dd:c25:c25:94de:bf32
522c19:dd:d9:dd:c25:c25:94de:bf33/1282c19:dd:d9:dd:c25:c25:94de:bf33
532c19:dd:d9:dd:c25:c25:94de:bf34/1282c19:dd:d9:dd:c25:c25:94de:bf34
542c19:dd:d9:dd:c25:c25:94de:bf35/1282c19:dd:d9:dd:c25:c25:94de:bf35
552c19:dd:d9:dd:c25:c25:94de:bf36/1282c19:dd:d9:dd:c25:c25:94de:bf36
562c19:dd:d9:dd:c25:c25:94de:bf37/1282c19:dd:d9:dd:c25:c25:94de:bf37
572c19:dd:d9:dd:c25:c25:94de:bf38/1282c19:dd:d9:dd:c25:c25:94de:bf38
582c19:dd:d9:dd:c25:c25:94de:bf39/1282c19:dd:d9:dd:c25:c25:94de:bf39
592c19:dd:d9:dd:c25:c25:94de:bf3a/1282c19:dd:d9:dd:c25:c25:94de:bf3a
602c19:dd:d9:dd:c25:c25:94de:bf3b/1282c19:dd:d9:dd:c25:c25:94de:bf3b
612c19:dd:d9:dd:c25:c25:94de:bf3c/1282c19:dd:d9:dd:c25:c25:94de:bf3c
622c19:dd:d9:dd:c25:c25:94de:bf3d/1282c19:dd:d9:dd:c25:c25:94de:bf3d
632c19:dd:d9:dd:c25:c25:94de:bf3e/1282c19:dd:d9:dd:c25:c25:94de:bf3e
642c19:dd:d9:dd:c25:c25:94de:bf3f/1282c19:dd:d9:dd:c25:c25:94de:bf3f
652c19:dd:d9:dd:c25:c25:94de:bf40/1282c19:dd:d9:dd:c25:c25:94de:bf40
662c19:dd:d9:dd:c25:c25:94de:bf41/1282c19:dd:d9:dd:c25:c25:94de:bf41
672c19:dd:d9:dd:c25:c25:94de:bf42/1282c19:dd:d9:dd:c25:c25:94de:bf42
682c19:dd:d9:dd:c25:c25:94de:bf43/1282c19:dd:d9:dd:c25:c25:94de:bf43
692c19:dd:d9:dd:c25:c25:94de:bf44/1282c19:dd:d9:dd:c25:c25:94de:bf44
702c19:dd:d9:dd:c25:c25:94de:bf45/1282c19:dd:d9:dd:c25:c25:94de:bf45
712c19:dd:d9:dd:c25:c25:94de:bf46/1282c19:dd:d9:dd:c25:c25:94de:bf46
722c19:dd:d9:dd:c25:c25:94de:bf47/1282c19:dd:d9:dd:c25:c25:94de:bf47
732c19:dd:d9:dd:c25:c25:94de:bf48/1282c19:dd:d9:dd:c25:c25:94de:bf48
742c19:dd:d9:dd:c25:c25:94de:bf49/1282c19:dd:d9:dd:c25:c25:94de:bf49
752c19:dd:d9:dd:c25:c25:94de:bf4a/1282c19:dd:d9:dd:c25:c25:94de:bf4a
762c19:dd:d9:dd:c25:c25:94de:bf4b/1282c19:dd:d9:dd:c25:c25:94de:bf4b
772c19:dd:d9:dd:c25:c25:94de:bf4c/1282c19:dd:d9:dd:c25:c25:94de:bf4c
782c19:dd:d9:dd:c25:c25:94de:bf4d/1282c19:dd:d9:dd:c25:c25:94de:bf4d
792c19:dd:d9:dd:c25:c25:94de:bf4e/1282c19:dd:d9:dd:c25:c25:94de:bf4e
802c19:dd:d9:dd:c25:c25:94de:bf4f/1282c19:dd:d9:dd:c25:c25:94de:bf4f
812c19:dd:d9:dd:c25:c25:94de:bf50/1282c19:dd:d9:dd:c25:c25:94de:bf50
822c19:dd:d9:dd:c25:c25:94de:bf51/1282c19:dd:d9:dd:c25:c25:94de:bf51
832c19:dd:d9:dd:c25:c25:94de:bf52/1282c19:dd:d9:dd:c25:c25:94de:bf52
842c19:dd:d9:dd:c25:c25:94de:bf53/1282c19:dd:d9:dd:c25:c25:94de:bf53
852c19:dd:d9:dd:c25:c25:94de:bf54/1282c19:dd:d9:dd:c25:c25:94de:bf54
862c19:dd:d9:dd:c25:c25:94de:bf55/1282c19:dd:d9:dd:c25:c25:94de:bf55
872c19:dd:d9:dd:c25:c25:94de:bf56/1282c19:dd:d9:dd:c25:c25:94de:bf56
882c19:dd:d9:dd:c25:c25:94de:bf57/1282c19:dd:d9:dd:c25:c25:94de:bf57
892c19:dd:d9:dd:c25:c25:94de:bf58/1282c19:dd:d9:dd:c25:c25:94de:bf58
902c19:dd:d9:dd:c25:c25:94de:bf59/1282c19:dd:d9:dd:c25:c25:94de:bf59
912c19:dd:d9:dd:c25:c25:94de:bf5a/1282c19:dd:d9:dd:c25:c25:94de:bf5a
922c19:dd:d9:dd:c25:c25:94de:bf5b/1282c19:dd:d9:dd:c25:c25:94de:bf5b
932c19:dd:d9:dd:c25:c25:94de:bf5c/1282c19:dd:d9:dd:c25:c25:94de:bf5c
942c19:dd:d9:dd:c25:c25:94de:bf5d/1282c19:dd:d9:dd:c25:c25:94de:bf5d
952c19:dd:d9:dd:c25:c25:94de:bf5e/1282c19:dd:d9:dd:c25:c25:94de:bf5e
962c19:dd:d9:dd:c25:c25:94de:bf5f/1282c19:dd:d9:dd:c25:c25:94de:bf5f
972c19:dd:d9:dd:c25:c25:94de:bf60/1282c19:dd:d9:dd:c25:c25:94de:bf60
982c19:dd:d9:dd:c25:c25:94de:bf61/1282c19:dd:d9:dd:c25:c25:94de:bf61
992c19:dd:d9:dd:c25:c25:94de:bf62/1282c19:dd:d9:dd:c25:c25:94de:bf62
1002c19:dd:d9:dd:c25:c25:94de:bf63/1282c19:dd:d9:dd:c25:c25:94de:bf63
1012c19:dd:d9:dd:c25:c25:94de:bf64/1282c19:dd:d9:dd:c25:c25:94de:bf64
1022c19:dd:d9:dd:c25:c25:94de:bf65/1282c19:dd:d9:dd:c25:c25:94de:bf65
1032c19:dd:d9:dd:c25:c25:94de:bf66/1282c19:dd:d9:dd:c25:c25:94de:bf66
1042c19:dd:d9:dd:c25:c25:94de:bf67/1282c19:dd:d9:dd:c25:c25:94de:bf67
1052c19:dd:d9:dd:c25:c25:94de:bf68/1282c19:dd:d9:dd:c25:c25:94de:bf68
1062c19:dd:d9:dd:c25:c25:94de:bf69/1282c19:dd:d9:dd:c25:c25:94de:bf69
1072c19:dd:d9:dd:c25:c25:94de:bf6a/1282c19:dd:d9:dd:c25:c25:94de:bf6a
1082c19:dd:d9:dd:c25:c25:94de:bf6b/1282c19:dd:d9:dd:c25:c25:94de:bf6b
1092c19:dd:d9:dd:c25:c25:94de:bf6c/1282c19:dd:d9:dd:c25:c25:94de:bf6c
1102c19:dd:d9:dd:c25:c25:94de:bf6d/1282c19:dd:d9:dd:c25:c25:94de:bf6d
1112c19:dd:d9:dd:c25:c25:94de:bf6e/1282c19:dd:d9:dd:c25:c25:94de:bf6e
1122c19:dd:d9:dd:c25:c25:94de:bf6f/1282c19:dd:d9:dd:c25:c25:94de:bf6f
1132c19:dd:d9:dd:c25:c25:94de:bf70/1282c19:dd:d9:dd:c25:c25:94de:bf70
1142c19:dd:d9:dd:c25:c25:94de:bf71/1282c19:dd:d9:dd:c25:c25:94de:bf71
1152c19:dd:d9:dd:c25:c25:94de:bf72/1282c19:dd:d9:dd:c25:c25:94de:bf72
1162c19:dd:d9:dd:c25:c25:94de:bf73/1282c19:dd:d9:dd:c25:c25:94de:bf73
1172c19:dd:d9:dd:c25:c25:94de:bf74/1282c19:dd:d9:dd:c25:c25:94de:bf74
1182c19:dd:d9:dd:c25:c25:94de:bf75/1282c19:dd:d9:dd:c25:c25:94de:bf75
1192c19:dd:d9:dd:c25:c25:94de:bf76/1282c19:dd:d9:dd:c25:c25:94de:bf76
1202c19:dd:d9:dd:c25:c25:94de:bf77/1282c19:dd:d9:dd:c25:c25:94de:bf77
1212c19:dd:d9:dd:c25:c25:94de:bf78/1282c19:dd:d9:dd:c25:c25:94de:bf78
1222c19:dd:d9:dd:c25:c25:94de:bf79/1282c19:dd:d9:dd:c25:c25:94de:bf79
1232c19:dd:d9:dd:c25:c25:94de:bf7a/1282c19:dd:d9:dd:c25:c25:94de:bf7a
1242c19:dd:d9:dd:c25:c25:94de:bf7b/1282c19:dd:d9:dd:c25:c25:94de:bf7b
1252c19:dd:d9:dd:c25:c25:94de:bf7c/1282c19:dd:d9:dd:c25:c25:94de:bf7c
1262c19:dd:d9:dd:c25:c25:94de:bf7d/1282c19:dd:d9:dd:c25:c25:94de:bf7d
1272c19:dd:d9:dd:c25:c25:94de:bf7e/1282c19:dd:d9:dd:c25:c25:94de:bf7e
1282c19:dd:d9:dd:c25:c25:94de:bf7f/1282c19:dd:d9:dd:c25:c25:94de:bf7f
1292c19:dd:d9:dd:c25:c25:94de:bf80/1282c19:dd:d9:dd:c25:c25:94de:bf80
1302c19:dd:d9:dd:c25:c25:94de:bf81/1282c19:dd:d9:dd:c25:c25:94de:bf81
1312c19:dd:d9:dd:c25:c25:94de:bf82/1282c19:dd:d9:dd:c25:c25:94de:bf82
1322c19:dd:d9:dd:c25:c25:94de:bf83/1282c19:dd:d9:dd:c25:c25:94de:bf83
1332c19:dd:d9:dd:c25:c25:94de:bf84/1282c19:dd:d9:dd:c25:c25:94de:bf84
1342c19:dd:d9:dd:c25:c25:94de:bf85/1282c19:dd:d9:dd:c25:c25:94de:bf85
1352c19:dd:d9:dd:c25:c25:94de:bf86/1282c19:dd:d9:dd:c25:c25:94de:bf86
1362c19:dd:d9:dd:c25:c25:94de:bf87/1282c19:dd:d9:dd:c25:c25:94de:bf87
1372c19:dd:d9:dd:c25:c25:94de:bf88/1282c19:dd:d9:dd:c25:c25:94de:bf88
1382c19:dd:d9:dd:c25:c25:94de:bf89/1282c19:dd:d9:dd:c25:c25:94de:bf89
1392c19:dd:d9:dd:c25:c25:94de:bf8a/1282c19:dd:d9:dd:c25:c25:94de:bf8a
1402c19:dd:d9:dd:c25:c25:94de:bf8b/1282c19:dd:d9:dd:c25:c25:94de:bf8b
1412c19:dd:d9:dd:c25:c25:94de:bf8c/1282c19:dd:d9:dd:c25:c25:94de:bf8c
1422c19:dd:d9:dd:c25:c25:94de:bf8d/1282c19:dd:d9:dd:c25:c25:94de:bf8d
1432c19:dd:d9:dd:c25:c25:94de:bf8e/1282c19:dd:d9:dd:c25:c25:94de:bf8e
1442c19:dd:d9:dd:c25:c25:94de:bf8f/1282c19:dd:d9:dd:c25:c25:94de:bf8f
1452c19:dd:d9:dd:c25:c25:94de:bf90/1282c19:dd:d9:dd:c25:c25:94de:bf90
1462c19:dd:d9:dd:c25:c25:94de:bf91/1282c19:dd:d9:dd:c25:c25:94de:bf91
1472c19:dd:d9:dd:c25:c25:94de:bf92/1282c19:dd:d9:dd:c25:c25:94de:bf92
1482c19:dd:d9:dd:c25:c25:94de:bf93/1282c19:dd:d9:dd:c25:c25:94de:bf93
1492c19:dd:d9:dd:c25:c25:94de:bf94/1282c19:dd:d9:dd:c25:c25:94de:bf94
1502c19:dd:d9:dd:c25:c25:94de:bf95/1282c19:dd:d9:dd:c25:c25:94de:bf95
1512c19:dd:d9:dd:c25:c25:94de:bf96/1282c19:dd:d9:dd:c25:c25:94de:bf96
1522c19:dd:d9:dd:c25:c25:94de:bf97/1282c19:dd:d9:dd:c25:c25:94de:bf97
1532c19:dd:d9:dd:c25:c25:94de:bf98/1282c19:dd:d9:dd:c25:c25:94de:bf98
1542c19:dd:d9:dd:c25:c25:94de:bf99/1282c19:dd:d9:dd:c25:c25:94de:bf99
1552c19:dd:d9:dd:c25:c25:94de:bf9a/1282c19:dd:d9:dd:c25:c25:94de:bf9a
1562c19:dd:d9:dd:c25:c25:94de:bf9b/1282c19:dd:d9:dd:c25:c25:94de:bf9b
1572c19:dd:d9:dd:c25:c25:94de:bf9c/1282c19:dd:d9:dd:c25:c25:94de:bf9c
1582c19:dd:d9:dd:c25:c25:94de:bf9d/1282c19:dd:d9:dd:c25:c25:94de:bf9d
1592c19:dd:d9:dd:c25:c25:94de:bf9e/1282c19:dd:d9:dd:c25:c25:94de:bf9e
1602c19:dd:d9:dd:c25:c25:94de:bf9f/1282c19:dd:d9:dd:c25:c25:94de:bf9f
1612c19:dd:d9:dd:c25:c25:94de:bfa0/1282c19:dd:d9:dd:c25:c25:94de:bfa0
1622c19:dd:d9:dd:c25:c25:94de:bfa1/1282c19:dd:d9:dd:c25:c25:94de:bfa1
1632c19:dd:d9:dd:c25:c25:94de:bfa2/1282c19:dd:d9:dd:c25:c25:94de:bfa2
1642c19:dd:d9:dd:c25:c25:94de:bfa3/1282c19:dd:d9:dd:c25:c25:94de:bfa3
1652c19:dd:d9:dd:c25:c25:94de:bfa4/1282c19:dd:d9:dd:c25:c25:94de:bfa4
1662c19:dd:d9:dd:c25:c25:94de:bfa5/1282c19:dd:d9:dd:c25:c25:94de:bfa5
1672c19:dd:d9:dd:c25:c25:94de:bfa6/1282c19:dd:d9:dd:c25:c25:94de:bfa6
1682c19:dd:d9:dd:c25:c25:94de:bfa7/1282c19:dd:d9:dd:c25:c25:94de:bfa7
1692c19:dd:d9:dd:c25:c25:94de:bfa8/1282c19:dd:d9:dd:c25:c25:94de:bfa8
1702c19:dd:d9:dd:c25:c25:94de:bfa9/1282c19:dd:d9:dd:c25:c25:94de:bfa9
1712c19:dd:d9:dd:c25:c25:94de:bfaa/1282c19:dd:d9:dd:c25:c25:94de:bfaa
1722c19:dd:d9:dd:c25:c25:94de:bfab/1282c19:dd:d9:dd:c25:c25:94de:bfab
1732c19:dd:d9:dd:c25:c25:94de:bfac/1282c19:dd:d9:dd:c25:c25:94de:bfac
1742c19:dd:d9:dd:c25:c25:94de:bfad/1282c19:dd:d9:dd:c25:c25:94de:bfad
1752c19:dd:d9:dd:c25:c25:94de:bfae/1282c19:dd:d9:dd:c25:c25:94de:bfae
1762c19:dd:d9:dd:c25:c25:94de:bfaf/1282c19:dd:d9:dd:c25:c25:94de:bfaf
1772c19:dd:d9:dd:c25:c25:94de:bfb0/1282c19:dd:d9:dd:c25:c25:94de:bfb0
1782c19:dd:d9:dd:c25:c25:94de:bfb1/1282c19:dd:d9:dd:c25:c25:94de:bfb1
1792c19:dd:d9:dd:c25:c25:94de:bfb2/1282c19:dd:d9:dd:c25:c25:94de:bfb2
1802c19:dd:d9:dd:c25:c25:94de:bfb3/1282c19:dd:d9:dd:c25:c25:94de:bfb3
1812c19:dd:d9:dd:c25:c25:94de:bfb4/1282c19:dd:d9:dd:c25:c25:94de:bfb4
1822c19:dd:d9:dd:c25:c25:94de:bfb5/1282c19:dd:d9:dd:c25:c25:94de:bfb5
1832c19:dd:d9:dd:c25:c25:94de:bfb6/1282c19:dd:d9:dd:c25:c25:94de:bfb6
1842c19:dd:d9:dd:c25:c25:94de:bfb7/1282c19:dd:d9:dd:c25:c25:94de:bfb7
1852c19:dd:d9:dd:c25:c25:94de:bfb8/1282c19:dd:d9:dd:c25:c25:94de:bfb8
1862c19:dd:d9:dd:c25:c25:94de:bfb9/1282c19:dd:d9:dd:c25:c25:94de:bfb9
1872c19:dd:d9:dd:c25:c25:94de:bfba/1282c19:dd:d9:dd:c25:c25:94de:bfba
1882c19:dd:d9:dd:c25:c25:94de:bfbb/1282c19:dd:d9:dd:c25:c25:94de:bfbb
1892c19:dd:d9:dd:c25:c25:94de:bfbc/1282c19:dd:d9:dd:c25:c25:94de:bfbc
1902c19:dd:d9:dd:c25:c25:94de:bfbd/1282c19:dd:d9:dd:c25:c25:94de:bfbd
1912c19:dd:d9:dd:c25:c25:94de:bfbe/1282c19:dd:d9:dd:c25:c25:94de:bfbe
1922c19:dd:d9:dd:c25:c25:94de:bfbf/1282c19:dd:d9:dd:c25:c25:94de:bfbf
1932c19:dd:d9:dd:c25:c25:94de:bfc0/1282c19:dd:d9:dd:c25:c25:94de:bfc0
1942c19:dd:d9:dd:c25:c25:94de:bfc1/1282c19:dd:d9:dd:c25:c25:94de:bfc1
1952c19:dd:d9:dd:c25:c25:94de:bfc2/1282c19:dd:d9:dd:c25:c25:94de:bfc2
1962c19:dd:d9:dd:c25:c25:94de:bfc3/1282c19:dd:d9:dd:c25:c25:94de:bfc3
1972c19:dd:d9:dd:c25:c25:94de:bfc4/1282c19:dd:d9:dd:c25:c25:94de:bfc4
1982c19:dd:d9:dd:c25:c25:94de:bfc5/1282c19:dd:d9:dd:c25:c25:94de:bfc5
1992c19:dd:d9:dd:c25:c25:94de:bfc6/1282c19:dd:d9:dd:c25:c25:94de:bfc6
2002c19:dd:d9:dd:c25:c25:94de:bfc7/1282c19:dd:d9:dd:c25:c25:94de:bfc7
2012c19:dd:d9:dd:c25:c25:94de:bfc8/1282c19:dd:d9:dd:c25:c25:94de:bfc8
2022c19:dd:d9:dd:c25:c25:94de:bfc9/1282c19:dd:d9:dd:c25:c25:94de:bfc9
2032c19:dd:d9:dd:c25:c25:94de:bfca/1282c19:dd:d9:dd:c25:c25:94de:bfca
2042c19:dd:d9:dd:c25:c25:94de:bfcb/1282c19:dd:d9:dd:c25:c25:94de:bfcb
2052c19:dd:d9:dd:c25:c25:94de:bfcc/1282c19:dd:d9:dd:c25:c25:94de:bfcc
2062c19:dd:d9:dd:c25:c25:94de:bfcd/1282c19:dd:d9:dd:c25:c25:94de:bfcd
2072c19:dd:d9:dd:c25:c25:94de:bfce/1282c19:dd:d9:dd:c25:c25:94de:bfce
2082c19:dd:d9:dd:c25:c25:94de:bfcf/1282c19:dd:d9:dd:c25:c25:94de:bfcf
2092c19:dd:d9:dd:c25:c25:94de:bfd0/1282c19:dd:d9:dd:c25:c25:94de:bfd0
2102c19:dd:d9:dd:c25:c25:94de:bfd1/1282c19:dd:d9:dd:c25:c25:94de:bfd1
2112c19:dd:d9:dd:c25:c25:94de:bfd2/1282c19:dd:d9:dd:c25:c25:94de:bfd2
2122c19:dd:d9:dd:c25:c25:94de:bfd3/1282c19:dd:d9:dd:c25:c25:94de:bfd3
2132c19:dd:d9:dd:c25:c25:94de:bfd4/1282c19:dd:d9:dd:c25:c25:94de:bfd4
2142c19:dd:d9:dd:c25:c25:94de:bfd5/1282c19:dd:d9:dd:c25:c25:94de:bfd5
2152c19:dd:d9:dd:c25:c25:94de:bfd6/1282c19:dd:d9:dd:c25:c25:94de:bfd6
2162c19:dd:d9:dd:c25:c25:94de:bfd7/1282c19:dd:d9:dd:c25:c25:94de:bfd7
2172c19:dd:d9:dd:c25:c25:94de:bfd8/1282c19:dd:d9:dd:c25:c25:94de:bfd8
2182c19:dd:d9:dd:c25:c25:94de:bfd9/1282c19:dd:d9:dd:c25:c25:94de:bfd9
2192c19:dd:d9:dd:c25:c25:94de:bfda/1282c19:dd:d9:dd:c25:c25:94de:bfda
2202c19:dd:d9:dd:c25:c25:94de:bfdb/1282c19:dd:d9:dd:c25:c25:94de:bfdb
2212c19:dd:d9:dd:c25:c25:94de:bfdc/1282c19:dd:d9:dd:c25:c25:94de:bfdc
2222c19:dd:d9:dd:c25:c25:94de:bfdd/1282c19:dd:d9:dd:c25:c25:94de:bfdd
2232c19:dd:d9:dd:c25:c25:94de:bfde/1282c19:dd:d9:dd:c25:c25:94de:bfde
2242c19:dd:d9:dd:c25:c25:94de:bfdf/1282c19:dd:d9:dd:c25:c25:94de:bfdf
2252c19:dd:d9:dd:c25:c25:94de:bfe0/1282c19:dd:d9:dd:c25:c25:94de:bfe0
2262c19:dd:d9:dd:c25:c25:94de:bfe1/1282c19:dd:d9:dd:c25:c25:94de:bfe1
2272c19:dd:d9:dd:c25:c25:94de:bfe2/1282c19:dd:d9:dd:c25:c25:94de:bfe2
2282c19:dd:d9:dd:c25:c25:94de:bfe3/1282c19:dd:d9:dd:c25:c25:94de:bfe3
2292c19:dd:d9:dd:c25:c25:94de:bfe4/1282c19:dd:d9:dd:c25:c25:94de:bfe4
2302c19:dd:d9:dd:c25:c25:94de:bfe5/1282c19:dd:d9:dd:c25:c25:94de:bfe5
2312c19:dd:d9:dd:c25:c25:94de:bfe6/1282c19:dd:d9:dd:c25:c25:94de:bfe6
2322c19:dd:d9:dd:c25:c25:94de:bfe7/1282c19:dd:d9:dd:c25:c25:94de:bfe7
2332c19:dd:d9:dd:c25:c25:94de:bfe8/1282c19:dd:d9:dd:c25:c25:94de:bfe8
2342c19:dd:d9:dd:c25:c25:94de:bfe9/1282c19:dd:d9:dd:c25:c25:94de:bfe9
2352c19:dd:d9:dd:c25:c25:94de:bfea/1282c19:dd:d9:dd:c25:c25:94de:bfea
2362c19:dd:d9:dd:c25:c25:94de:bfeb/1282c19:dd:d9:dd:c25:c25:94de:bfeb
2372c19:dd:d9:dd:c25:c25:94de:bfec/1282c19:dd:d9:dd:c25:c25:94de:bfec
2382c19:dd:d9:dd:c25:c25:94de:bfed/1282c19:dd:d9:dd:c25:c25:94de:bfed
2392c19:dd:d9:dd:c25:c25:94de:bfee/1282c19:dd:d9:dd:c25:c25:94de:bfee
2402c19:dd:d9:dd:c25:c25:94de:bfef/1282c19:dd:d9:dd:c25:c25:94de:bfef
2412c19:dd:d9:dd:c25:c25:94de:bff0/1282c19:dd:d9:dd:c25:c25:94de:bff0
2422c19:dd:d9:dd:c25:c25:94de:bff1/1282c19:dd:d9:dd:c25:c25:94de:bff1
2432c19:dd:d9:dd:c25:c25:94de:bff2/1282c19:dd:d9:dd:c25:c25:94de:bff2
2442c19:dd:d9:dd:c25:c25:94de:bff3/1282c19:dd:d9:dd:c25:c25:94de:bff3
2452c19:dd:d9:dd:c25:c25:94de:bff4/1282c19:dd:d9:dd:c25:c25:94de:bff4
2462c19:dd:d9:dd:c25:c25:94de:bff5/1282c19:dd:d9:dd:c25:c25:94de:bff5
2472c19:dd:d9:dd:c25:c25:94de:bff6/1282c19:dd:d9:dd:c25:c25:94de:bff6
2482c19:dd:d9:dd:c25:c25:94de:bff7/1282c19:dd:d9:dd:c25:c25:94de:bff7
2492c19:dd:d9:dd:c25:c25:94de:bff8/1282c19:dd:d9:dd:c25:c25:94de:bff8
2502c19:dd:d9:dd:c25:c25:94de:bff9/1282c19:dd:d9:dd:c25:c25:94de:bff9
2512c19:dd:d9:dd:c25:c25:94de:bffa/1282c19:dd:d9:dd:c25:c25:94de:bffa
2522c19:dd:d9:dd:c25:c25:94de:bffb/1282c19:dd:d9:dd:c25:c25:94de:bffb
2532c19:dd:d9:dd:c25:c25:94de:bffc/1282c19:dd:d9:dd:c25:c25:94de:bffc
2542c19:dd:d9:dd:c25:c25:94de:bffd/1282c19:dd:d9:dd:c25:c25:94de:bffd
2552c19:dd:d9:dd:c25:c25:94de:bffe/1282c19:dd:d9:dd:c25:c25:94de:bffe
2562c19:dd:d9:dd:c25:c25:94de:bfff/1282c19:dd:d9:dd:c25:c25:94de:bfff

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.