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:ec00:c25:c25e:dd:ddca:de00/119
First address
2c19:dd:ec00:c25:c25e:dd:ddca:de00
Last address
2c19:dd:ec00:c25:c25e:dd:ddca:dfff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:ec00:0c25:c25e:00dd:ddca:de00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
e.d.a.c.d.d.d.d.0.0.e.5.2.c.5.2.c.0.0.0.c.e.d.d.0.0.9.1.c.2.ip6.arpa
f.d.a.c.d.d.d.d.0.0.e.5.2.c.5.2.c.0.0.0.c.e.d.d.0.0.9.1.c.2.ip6.arpa
/119 is not on a 4-bit boundary, so it takes 2 /120 zones.
Split into smaller subnets/127
/120 (2)/121 (4)/122 (8)/123 (16)/124 (32)/127 (256)/128 (512)

2c19:dd:ec00:c25:c25e:dd:ddca:de00/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:ddca:de00/1272c19:dd:ec00:c25:c25e:dd:ddca:de01
22c19:dd:ec00:c25:c25e:dd:ddca:de02/1272c19:dd:ec00:c25:c25e:dd:ddca:de03
32c19:dd:ec00:c25:c25e:dd:ddca:de04/1272c19:dd:ec00:c25:c25e:dd:ddca:de05
42c19:dd:ec00:c25:c25e:dd:ddca:de06/1272c19:dd:ec00:c25:c25e:dd:ddca:de07
52c19:dd:ec00:c25:c25e:dd:ddca:de08/1272c19:dd:ec00:c25:c25e:dd:ddca:de09
62c19:dd:ec00:c25:c25e:dd:ddca:de0a/1272c19:dd:ec00:c25:c25e:dd:ddca:de0b
72c19:dd:ec00:c25:c25e:dd:ddca:de0c/1272c19:dd:ec00:c25:c25e:dd:ddca:de0d
82c19:dd:ec00:c25:c25e:dd:ddca:de0e/1272c19:dd:ec00:c25:c25e:dd:ddca:de0f
92c19:dd:ec00:c25:c25e:dd:ddca:de10/1272c19:dd:ec00:c25:c25e:dd:ddca:de11
102c19:dd:ec00:c25:c25e:dd:ddca:de12/1272c19:dd:ec00:c25:c25e:dd:ddca:de13
112c19:dd:ec00:c25:c25e:dd:ddca:de14/1272c19:dd:ec00:c25:c25e:dd:ddca:de15
122c19:dd:ec00:c25:c25e:dd:ddca:de16/1272c19:dd:ec00:c25:c25e:dd:ddca:de17
132c19:dd:ec00:c25:c25e:dd:ddca:de18/1272c19:dd:ec00:c25:c25e:dd:ddca:de19
142c19:dd:ec00:c25:c25e:dd:ddca:de1a/1272c19:dd:ec00:c25:c25e:dd:ddca:de1b
152c19:dd:ec00:c25:c25e:dd:ddca:de1c/1272c19:dd:ec00:c25:c25e:dd:ddca:de1d
162c19:dd:ec00:c25:c25e:dd:ddca:de1e/1272c19:dd:ec00:c25:c25e:dd:ddca:de1f
172c19:dd:ec00:c25:c25e:dd:ddca:de20/1272c19:dd:ec00:c25:c25e:dd:ddca:de21
182c19:dd:ec00:c25:c25e:dd:ddca:de22/1272c19:dd:ec00:c25:c25e:dd:ddca:de23
192c19:dd:ec00:c25:c25e:dd:ddca:de24/1272c19:dd:ec00:c25:c25e:dd:ddca:de25
202c19:dd:ec00:c25:c25e:dd:ddca:de26/1272c19:dd:ec00:c25:c25e:dd:ddca:de27
212c19:dd:ec00:c25:c25e:dd:ddca:de28/1272c19:dd:ec00:c25:c25e:dd:ddca:de29
222c19:dd:ec00:c25:c25e:dd:ddca:de2a/1272c19:dd:ec00:c25:c25e:dd:ddca:de2b
232c19:dd:ec00:c25:c25e:dd:ddca:de2c/1272c19:dd:ec00:c25:c25e:dd:ddca:de2d
242c19:dd:ec00:c25:c25e:dd:ddca:de2e/1272c19:dd:ec00:c25:c25e:dd:ddca:de2f
252c19:dd:ec00:c25:c25e:dd:ddca:de30/1272c19:dd:ec00:c25:c25e:dd:ddca:de31
262c19:dd:ec00:c25:c25e:dd:ddca:de32/1272c19:dd:ec00:c25:c25e:dd:ddca:de33
272c19:dd:ec00:c25:c25e:dd:ddca:de34/1272c19:dd:ec00:c25:c25e:dd:ddca:de35
282c19:dd:ec00:c25:c25e:dd:ddca:de36/1272c19:dd:ec00:c25:c25e:dd:ddca:de37
292c19:dd:ec00:c25:c25e:dd:ddca:de38/1272c19:dd:ec00:c25:c25e:dd:ddca:de39
302c19:dd:ec00:c25:c25e:dd:ddca:de3a/1272c19:dd:ec00:c25:c25e:dd:ddca:de3b
312c19:dd:ec00:c25:c25e:dd:ddca:de3c/1272c19:dd:ec00:c25:c25e:dd:ddca:de3d
322c19:dd:ec00:c25:c25e:dd:ddca:de3e/1272c19:dd:ec00:c25:c25e:dd:ddca:de3f
332c19:dd:ec00:c25:c25e:dd:ddca:de40/1272c19:dd:ec00:c25:c25e:dd:ddca:de41
342c19:dd:ec00:c25:c25e:dd:ddca:de42/1272c19:dd:ec00:c25:c25e:dd:ddca:de43
352c19:dd:ec00:c25:c25e:dd:ddca:de44/1272c19:dd:ec00:c25:c25e:dd:ddca:de45
362c19:dd:ec00:c25:c25e:dd:ddca:de46/1272c19:dd:ec00:c25:c25e:dd:ddca:de47
372c19:dd:ec00:c25:c25e:dd:ddca:de48/1272c19:dd:ec00:c25:c25e:dd:ddca:de49
382c19:dd:ec00:c25:c25e:dd:ddca:de4a/1272c19:dd:ec00:c25:c25e:dd:ddca:de4b
392c19:dd:ec00:c25:c25e:dd:ddca:de4c/1272c19:dd:ec00:c25:c25e:dd:ddca:de4d
402c19:dd:ec00:c25:c25e:dd:ddca:de4e/1272c19:dd:ec00:c25:c25e:dd:ddca:de4f
412c19:dd:ec00:c25:c25e:dd:ddca:de50/1272c19:dd:ec00:c25:c25e:dd:ddca:de51
422c19:dd:ec00:c25:c25e:dd:ddca:de52/1272c19:dd:ec00:c25:c25e:dd:ddca:de53
432c19:dd:ec00:c25:c25e:dd:ddca:de54/1272c19:dd:ec00:c25:c25e:dd:ddca:de55
442c19:dd:ec00:c25:c25e:dd:ddca:de56/1272c19:dd:ec00:c25:c25e:dd:ddca:de57
452c19:dd:ec00:c25:c25e:dd:ddca:de58/1272c19:dd:ec00:c25:c25e:dd:ddca:de59
462c19:dd:ec00:c25:c25e:dd:ddca:de5a/1272c19:dd:ec00:c25:c25e:dd:ddca:de5b
472c19:dd:ec00:c25:c25e:dd:ddca:de5c/1272c19:dd:ec00:c25:c25e:dd:ddca:de5d
482c19:dd:ec00:c25:c25e:dd:ddca:de5e/1272c19:dd:ec00:c25:c25e:dd:ddca:de5f
492c19:dd:ec00:c25:c25e:dd:ddca:de60/1272c19:dd:ec00:c25:c25e:dd:ddca:de61
502c19:dd:ec00:c25:c25e:dd:ddca:de62/1272c19:dd:ec00:c25:c25e:dd:ddca:de63
512c19:dd:ec00:c25:c25e:dd:ddca:de64/1272c19:dd:ec00:c25:c25e:dd:ddca:de65
522c19:dd:ec00:c25:c25e:dd:ddca:de66/1272c19:dd:ec00:c25:c25e:dd:ddca:de67
532c19:dd:ec00:c25:c25e:dd:ddca:de68/1272c19:dd:ec00:c25:c25e:dd:ddca:de69
542c19:dd:ec00:c25:c25e:dd:ddca:de6a/1272c19:dd:ec00:c25:c25e:dd:ddca:de6b
552c19:dd:ec00:c25:c25e:dd:ddca:de6c/1272c19:dd:ec00:c25:c25e:dd:ddca:de6d
562c19:dd:ec00:c25:c25e:dd:ddca:de6e/1272c19:dd:ec00:c25:c25e:dd:ddca:de6f
572c19:dd:ec00:c25:c25e:dd:ddca:de70/1272c19:dd:ec00:c25:c25e:dd:ddca:de71
582c19:dd:ec00:c25:c25e:dd:ddca:de72/1272c19:dd:ec00:c25:c25e:dd:ddca:de73
592c19:dd:ec00:c25:c25e:dd:ddca:de74/1272c19:dd:ec00:c25:c25e:dd:ddca:de75
602c19:dd:ec00:c25:c25e:dd:ddca:de76/1272c19:dd:ec00:c25:c25e:dd:ddca:de77
612c19:dd:ec00:c25:c25e:dd:ddca:de78/1272c19:dd:ec00:c25:c25e:dd:ddca:de79
622c19:dd:ec00:c25:c25e:dd:ddca:de7a/1272c19:dd:ec00:c25:c25e:dd:ddca:de7b
632c19:dd:ec00:c25:c25e:dd:ddca:de7c/1272c19:dd:ec00:c25:c25e:dd:ddca:de7d
642c19:dd:ec00:c25:c25e:dd:ddca:de7e/1272c19:dd:ec00:c25:c25e:dd:ddca:de7f
652c19:dd:ec00:c25:c25e:dd:ddca:de80/1272c19:dd:ec00:c25:c25e:dd:ddca:de81
662c19:dd:ec00:c25:c25e:dd:ddca:de82/1272c19:dd:ec00:c25:c25e:dd:ddca:de83
672c19:dd:ec00:c25:c25e:dd:ddca:de84/1272c19:dd:ec00:c25:c25e:dd:ddca:de85
682c19:dd:ec00:c25:c25e:dd:ddca:de86/1272c19:dd:ec00:c25:c25e:dd:ddca:de87
692c19:dd:ec00:c25:c25e:dd:ddca:de88/1272c19:dd:ec00:c25:c25e:dd:ddca:de89
702c19:dd:ec00:c25:c25e:dd:ddca:de8a/1272c19:dd:ec00:c25:c25e:dd:ddca:de8b
712c19:dd:ec00:c25:c25e:dd:ddca:de8c/1272c19:dd:ec00:c25:c25e:dd:ddca:de8d
722c19:dd:ec00:c25:c25e:dd:ddca:de8e/1272c19:dd:ec00:c25:c25e:dd:ddca:de8f
732c19:dd:ec00:c25:c25e:dd:ddca:de90/1272c19:dd:ec00:c25:c25e:dd:ddca:de91
742c19:dd:ec00:c25:c25e:dd:ddca:de92/1272c19:dd:ec00:c25:c25e:dd:ddca:de93
752c19:dd:ec00:c25:c25e:dd:ddca:de94/1272c19:dd:ec00:c25:c25e:dd:ddca:de95
762c19:dd:ec00:c25:c25e:dd:ddca:de96/1272c19:dd:ec00:c25:c25e:dd:ddca:de97
772c19:dd:ec00:c25:c25e:dd:ddca:de98/1272c19:dd:ec00:c25:c25e:dd:ddca:de99
782c19:dd:ec00:c25:c25e:dd:ddca:de9a/1272c19:dd:ec00:c25:c25e:dd:ddca:de9b
792c19:dd:ec00:c25:c25e:dd:ddca:de9c/1272c19:dd:ec00:c25:c25e:dd:ddca:de9d
802c19:dd:ec00:c25:c25e:dd:ddca:de9e/1272c19:dd:ec00:c25:c25e:dd:ddca:de9f
812c19:dd:ec00:c25:c25e:dd:ddca:dea0/1272c19:dd:ec00:c25:c25e:dd:ddca:dea1
822c19:dd:ec00:c25:c25e:dd:ddca:dea2/1272c19:dd:ec00:c25:c25e:dd:ddca:dea3
832c19:dd:ec00:c25:c25e:dd:ddca:dea4/1272c19:dd:ec00:c25:c25e:dd:ddca:dea5
842c19:dd:ec00:c25:c25e:dd:ddca:dea6/1272c19:dd:ec00:c25:c25e:dd:ddca:dea7
852c19:dd:ec00:c25:c25e:dd:ddca:dea8/1272c19:dd:ec00:c25:c25e:dd:ddca:dea9
862c19:dd:ec00:c25:c25e:dd:ddca:deaa/1272c19:dd:ec00:c25:c25e:dd:ddca:deab
872c19:dd:ec00:c25:c25e:dd:ddca:deac/1272c19:dd:ec00:c25:c25e:dd:ddca:dead
882c19:dd:ec00:c25:c25e:dd:ddca:deae/1272c19:dd:ec00:c25:c25e:dd:ddca:deaf
892c19:dd:ec00:c25:c25e:dd:ddca:deb0/1272c19:dd:ec00:c25:c25e:dd:ddca:deb1
902c19:dd:ec00:c25:c25e:dd:ddca:deb2/1272c19:dd:ec00:c25:c25e:dd:ddca:deb3
912c19:dd:ec00:c25:c25e:dd:ddca:deb4/1272c19:dd:ec00:c25:c25e:dd:ddca:deb5
922c19:dd:ec00:c25:c25e:dd:ddca:deb6/1272c19:dd:ec00:c25:c25e:dd:ddca:deb7
932c19:dd:ec00:c25:c25e:dd:ddca:deb8/1272c19:dd:ec00:c25:c25e:dd:ddca:deb9
942c19:dd:ec00:c25:c25e:dd:ddca:deba/1272c19:dd:ec00:c25:c25e:dd:ddca:debb
952c19:dd:ec00:c25:c25e:dd:ddca:debc/1272c19:dd:ec00:c25:c25e:dd:ddca:debd
962c19:dd:ec00:c25:c25e:dd:ddca:debe/1272c19:dd:ec00:c25:c25e:dd:ddca:debf
972c19:dd:ec00:c25:c25e:dd:ddca:dec0/1272c19:dd:ec00:c25:c25e:dd:ddca:dec1
982c19:dd:ec00:c25:c25e:dd:ddca:dec2/1272c19:dd:ec00:c25:c25e:dd:ddca:dec3
992c19:dd:ec00:c25:c25e:dd:ddca:dec4/1272c19:dd:ec00:c25:c25e:dd:ddca:dec5
1002c19:dd:ec00:c25:c25e:dd:ddca:dec6/1272c19:dd:ec00:c25:c25e:dd:ddca:dec7
1012c19:dd:ec00:c25:c25e:dd:ddca:dec8/1272c19:dd:ec00:c25:c25e:dd:ddca:dec9
1022c19:dd:ec00:c25:c25e:dd:ddca:deca/1272c19:dd:ec00:c25:c25e:dd:ddca:decb
1032c19:dd:ec00:c25:c25e:dd:ddca:decc/1272c19:dd:ec00:c25:c25e:dd:ddca:decd
1042c19:dd:ec00:c25:c25e:dd:ddca:dece/1272c19:dd:ec00:c25:c25e:dd:ddca:decf
1052c19:dd:ec00:c25:c25e:dd:ddca:ded0/1272c19:dd:ec00:c25:c25e:dd:ddca:ded1
1062c19:dd:ec00:c25:c25e:dd:ddca:ded2/1272c19:dd:ec00:c25:c25e:dd:ddca:ded3
1072c19:dd:ec00:c25:c25e:dd:ddca:ded4/1272c19:dd:ec00:c25:c25e:dd:ddca:ded5
1082c19:dd:ec00:c25:c25e:dd:ddca:ded6/1272c19:dd:ec00:c25:c25e:dd:ddca:ded7
1092c19:dd:ec00:c25:c25e:dd:ddca:ded8/1272c19:dd:ec00:c25:c25e:dd:ddca:ded9
1102c19:dd:ec00:c25:c25e:dd:ddca:deda/1272c19:dd:ec00:c25:c25e:dd:ddca:dedb
1112c19:dd:ec00:c25:c25e:dd:ddca:dedc/1272c19:dd:ec00:c25:c25e:dd:ddca:dedd
1122c19:dd:ec00:c25:c25e:dd:ddca:dede/1272c19:dd:ec00:c25:c25e:dd:ddca:dedf
1132c19:dd:ec00:c25:c25e:dd:ddca:dee0/1272c19:dd:ec00:c25:c25e:dd:ddca:dee1
1142c19:dd:ec00:c25:c25e:dd:ddca:dee2/1272c19:dd:ec00:c25:c25e:dd:ddca:dee3
1152c19:dd:ec00:c25:c25e:dd:ddca:dee4/1272c19:dd:ec00:c25:c25e:dd:ddca:dee5
1162c19:dd:ec00:c25:c25e:dd:ddca:dee6/1272c19:dd:ec00:c25:c25e:dd:ddca:dee7
1172c19:dd:ec00:c25:c25e:dd:ddca:dee8/1272c19:dd:ec00:c25:c25e:dd:ddca:dee9
1182c19:dd:ec00:c25:c25e:dd:ddca:deea/1272c19:dd:ec00:c25:c25e:dd:ddca:deeb
1192c19:dd:ec00:c25:c25e:dd:ddca:deec/1272c19:dd:ec00:c25:c25e:dd:ddca:deed
1202c19:dd:ec00:c25:c25e:dd:ddca:deee/1272c19:dd:ec00:c25:c25e:dd:ddca:deef
1212c19:dd:ec00:c25:c25e:dd:ddca:def0/1272c19:dd:ec00:c25:c25e:dd:ddca:def1
1222c19:dd:ec00:c25:c25e:dd:ddca:def2/1272c19:dd:ec00:c25:c25e:dd:ddca:def3
1232c19:dd:ec00:c25:c25e:dd:ddca:def4/1272c19:dd:ec00:c25:c25e:dd:ddca:def5
1242c19:dd:ec00:c25:c25e:dd:ddca:def6/1272c19:dd:ec00:c25:c25e:dd:ddca:def7
1252c19:dd:ec00:c25:c25e:dd:ddca:def8/1272c19:dd:ec00:c25:c25e:dd:ddca:def9
1262c19:dd:ec00:c25:c25e:dd:ddca:defa/1272c19:dd:ec00:c25:c25e:dd:ddca:defb
1272c19:dd:ec00:c25:c25e:dd:ddca:defc/1272c19:dd:ec00:c25:c25e:dd:ddca:defd
1282c19:dd:ec00:c25:c25e:dd:ddca:defe/1272c19:dd:ec00:c25:c25e:dd:ddca:deff
1292c19:dd:ec00:c25:c25e:dd:ddca:df00/1272c19:dd:ec00:c25:c25e:dd:ddca:df01
1302c19:dd:ec00:c25:c25e:dd:ddca:df02/1272c19:dd:ec00:c25:c25e:dd:ddca:df03
1312c19:dd:ec00:c25:c25e:dd:ddca:df04/1272c19:dd:ec00:c25:c25e:dd:ddca:df05
1322c19:dd:ec00:c25:c25e:dd:ddca:df06/1272c19:dd:ec00:c25:c25e:dd:ddca:df07
1332c19:dd:ec00:c25:c25e:dd:ddca:df08/1272c19:dd:ec00:c25:c25e:dd:ddca:df09
1342c19:dd:ec00:c25:c25e:dd:ddca:df0a/1272c19:dd:ec00:c25:c25e:dd:ddca:df0b
1352c19:dd:ec00:c25:c25e:dd:ddca:df0c/1272c19:dd:ec00:c25:c25e:dd:ddca:df0d
1362c19:dd:ec00:c25:c25e:dd:ddca:df0e/1272c19:dd:ec00:c25:c25e:dd:ddca:df0f
1372c19:dd:ec00:c25:c25e:dd:ddca:df10/1272c19:dd:ec00:c25:c25e:dd:ddca:df11
1382c19:dd:ec00:c25:c25e:dd:ddca:df12/1272c19:dd:ec00:c25:c25e:dd:ddca:df13
1392c19:dd:ec00:c25:c25e:dd:ddca:df14/1272c19:dd:ec00:c25:c25e:dd:ddca:df15
1402c19:dd:ec00:c25:c25e:dd:ddca:df16/1272c19:dd:ec00:c25:c25e:dd:ddca:df17
1412c19:dd:ec00:c25:c25e:dd:ddca:df18/1272c19:dd:ec00:c25:c25e:dd:ddca:df19
1422c19:dd:ec00:c25:c25e:dd:ddca:df1a/1272c19:dd:ec00:c25:c25e:dd:ddca:df1b
1432c19:dd:ec00:c25:c25e:dd:ddca:df1c/1272c19:dd:ec00:c25:c25e:dd:ddca:df1d
1442c19:dd:ec00:c25:c25e:dd:ddca:df1e/1272c19:dd:ec00:c25:c25e:dd:ddca:df1f
1452c19:dd:ec00:c25:c25e:dd:ddca:df20/1272c19:dd:ec00:c25:c25e:dd:ddca:df21
1462c19:dd:ec00:c25:c25e:dd:ddca:df22/1272c19:dd:ec00:c25:c25e:dd:ddca:df23
1472c19:dd:ec00:c25:c25e:dd:ddca:df24/1272c19:dd:ec00:c25:c25e:dd:ddca:df25
1482c19:dd:ec00:c25:c25e:dd:ddca:df26/1272c19:dd:ec00:c25:c25e:dd:ddca:df27
1492c19:dd:ec00:c25:c25e:dd:ddca:df28/1272c19:dd:ec00:c25:c25e:dd:ddca:df29
1502c19:dd:ec00:c25:c25e:dd:ddca:df2a/1272c19:dd:ec00:c25:c25e:dd:ddca:df2b
1512c19:dd:ec00:c25:c25e:dd:ddca:df2c/1272c19:dd:ec00:c25:c25e:dd:ddca:df2d
1522c19:dd:ec00:c25:c25e:dd:ddca:df2e/1272c19:dd:ec00:c25:c25e:dd:ddca:df2f
1532c19:dd:ec00:c25:c25e:dd:ddca:df30/1272c19:dd:ec00:c25:c25e:dd:ddca:df31
1542c19:dd:ec00:c25:c25e:dd:ddca:df32/1272c19:dd:ec00:c25:c25e:dd:ddca:df33
1552c19:dd:ec00:c25:c25e:dd:ddca:df34/1272c19:dd:ec00:c25:c25e:dd:ddca:df35
1562c19:dd:ec00:c25:c25e:dd:ddca:df36/1272c19:dd:ec00:c25:c25e:dd:ddca:df37
1572c19:dd:ec00:c25:c25e:dd:ddca:df38/1272c19:dd:ec00:c25:c25e:dd:ddca:df39
1582c19:dd:ec00:c25:c25e:dd:ddca:df3a/1272c19:dd:ec00:c25:c25e:dd:ddca:df3b
1592c19:dd:ec00:c25:c25e:dd:ddca:df3c/1272c19:dd:ec00:c25:c25e:dd:ddca:df3d
1602c19:dd:ec00:c25:c25e:dd:ddca:df3e/1272c19:dd:ec00:c25:c25e:dd:ddca:df3f
1612c19:dd:ec00:c25:c25e:dd:ddca:df40/1272c19:dd:ec00:c25:c25e:dd:ddca:df41
1622c19:dd:ec00:c25:c25e:dd:ddca:df42/1272c19:dd:ec00:c25:c25e:dd:ddca:df43
1632c19:dd:ec00:c25:c25e:dd:ddca:df44/1272c19:dd:ec00:c25:c25e:dd:ddca:df45
1642c19:dd:ec00:c25:c25e:dd:ddca:df46/1272c19:dd:ec00:c25:c25e:dd:ddca:df47
1652c19:dd:ec00:c25:c25e:dd:ddca:df48/1272c19:dd:ec00:c25:c25e:dd:ddca:df49
1662c19:dd:ec00:c25:c25e:dd:ddca:df4a/1272c19:dd:ec00:c25:c25e:dd:ddca:df4b
1672c19:dd:ec00:c25:c25e:dd:ddca:df4c/1272c19:dd:ec00:c25:c25e:dd:ddca:df4d
1682c19:dd:ec00:c25:c25e:dd:ddca:df4e/1272c19:dd:ec00:c25:c25e:dd:ddca:df4f
1692c19:dd:ec00:c25:c25e:dd:ddca:df50/1272c19:dd:ec00:c25:c25e:dd:ddca:df51
1702c19:dd:ec00:c25:c25e:dd:ddca:df52/1272c19:dd:ec00:c25:c25e:dd:ddca:df53
1712c19:dd:ec00:c25:c25e:dd:ddca:df54/1272c19:dd:ec00:c25:c25e:dd:ddca:df55
1722c19:dd:ec00:c25:c25e:dd:ddca:df56/1272c19:dd:ec00:c25:c25e:dd:ddca:df57
1732c19:dd:ec00:c25:c25e:dd:ddca:df58/1272c19:dd:ec00:c25:c25e:dd:ddca:df59
1742c19:dd:ec00:c25:c25e:dd:ddca:df5a/1272c19:dd:ec00:c25:c25e:dd:ddca:df5b
1752c19:dd:ec00:c25:c25e:dd:ddca:df5c/1272c19:dd:ec00:c25:c25e:dd:ddca:df5d
1762c19:dd:ec00:c25:c25e:dd:ddca:df5e/1272c19:dd:ec00:c25:c25e:dd:ddca:df5f
1772c19:dd:ec00:c25:c25e:dd:ddca:df60/1272c19:dd:ec00:c25:c25e:dd:ddca:df61
1782c19:dd:ec00:c25:c25e:dd:ddca:df62/1272c19:dd:ec00:c25:c25e:dd:ddca:df63
1792c19:dd:ec00:c25:c25e:dd:ddca:df64/1272c19:dd:ec00:c25:c25e:dd:ddca:df65
1802c19:dd:ec00:c25:c25e:dd:ddca:df66/1272c19:dd:ec00:c25:c25e:dd:ddca:df67
1812c19:dd:ec00:c25:c25e:dd:ddca:df68/1272c19:dd:ec00:c25:c25e:dd:ddca:df69
1822c19:dd:ec00:c25:c25e:dd:ddca:df6a/1272c19:dd:ec00:c25:c25e:dd:ddca:df6b
1832c19:dd:ec00:c25:c25e:dd:ddca:df6c/1272c19:dd:ec00:c25:c25e:dd:ddca:df6d
1842c19:dd:ec00:c25:c25e:dd:ddca:df6e/1272c19:dd:ec00:c25:c25e:dd:ddca:df6f
1852c19:dd:ec00:c25:c25e:dd:ddca:df70/1272c19:dd:ec00:c25:c25e:dd:ddca:df71
1862c19:dd:ec00:c25:c25e:dd:ddca:df72/1272c19:dd:ec00:c25:c25e:dd:ddca:df73
1872c19:dd:ec00:c25:c25e:dd:ddca:df74/1272c19:dd:ec00:c25:c25e:dd:ddca:df75
1882c19:dd:ec00:c25:c25e:dd:ddca:df76/1272c19:dd:ec00:c25:c25e:dd:ddca:df77
1892c19:dd:ec00:c25:c25e:dd:ddca:df78/1272c19:dd:ec00:c25:c25e:dd:ddca:df79
1902c19:dd:ec00:c25:c25e:dd:ddca:df7a/1272c19:dd:ec00:c25:c25e:dd:ddca:df7b
1912c19:dd:ec00:c25:c25e:dd:ddca:df7c/1272c19:dd:ec00:c25:c25e:dd:ddca:df7d
1922c19:dd:ec00:c25:c25e:dd:ddca:df7e/1272c19:dd:ec00:c25:c25e:dd:ddca:df7f
1932c19:dd:ec00:c25:c25e:dd:ddca:df80/1272c19:dd:ec00:c25:c25e:dd:ddca:df81
1942c19:dd:ec00:c25:c25e:dd:ddca:df82/1272c19:dd:ec00:c25:c25e:dd:ddca:df83
1952c19:dd:ec00:c25:c25e:dd:ddca:df84/1272c19:dd:ec00:c25:c25e:dd:ddca:df85
1962c19:dd:ec00:c25:c25e:dd:ddca:df86/1272c19:dd:ec00:c25:c25e:dd:ddca:df87
1972c19:dd:ec00:c25:c25e:dd:ddca:df88/1272c19:dd:ec00:c25:c25e:dd:ddca:df89
1982c19:dd:ec00:c25:c25e:dd:ddca:df8a/1272c19:dd:ec00:c25:c25e:dd:ddca:df8b
1992c19:dd:ec00:c25:c25e:dd:ddca:df8c/1272c19:dd:ec00:c25:c25e:dd:ddca:df8d
2002c19:dd:ec00:c25:c25e:dd:ddca:df8e/1272c19:dd:ec00:c25:c25e:dd:ddca:df8f
2012c19:dd:ec00:c25:c25e:dd:ddca:df90/1272c19:dd:ec00:c25:c25e:dd:ddca:df91
2022c19:dd:ec00:c25:c25e:dd:ddca:df92/1272c19:dd:ec00:c25:c25e:dd:ddca:df93
2032c19:dd:ec00:c25:c25e:dd:ddca:df94/1272c19:dd:ec00:c25:c25e:dd:ddca:df95
2042c19:dd:ec00:c25:c25e:dd:ddca:df96/1272c19:dd:ec00:c25:c25e:dd:ddca:df97
2052c19:dd:ec00:c25:c25e:dd:ddca:df98/1272c19:dd:ec00:c25:c25e:dd:ddca:df99
2062c19:dd:ec00:c25:c25e:dd:ddca:df9a/1272c19:dd:ec00:c25:c25e:dd:ddca:df9b
2072c19:dd:ec00:c25:c25e:dd:ddca:df9c/1272c19:dd:ec00:c25:c25e:dd:ddca:df9d
2082c19:dd:ec00:c25:c25e:dd:ddca:df9e/1272c19:dd:ec00:c25:c25e:dd:ddca:df9f
2092c19:dd:ec00:c25:c25e:dd:ddca:dfa0/1272c19:dd:ec00:c25:c25e:dd:ddca:dfa1
2102c19:dd:ec00:c25:c25e:dd:ddca:dfa2/1272c19:dd:ec00:c25:c25e:dd:ddca:dfa3
2112c19:dd:ec00:c25:c25e:dd:ddca:dfa4/1272c19:dd:ec00:c25:c25e:dd:ddca:dfa5
2122c19:dd:ec00:c25:c25e:dd:ddca:dfa6/1272c19:dd:ec00:c25:c25e:dd:ddca:dfa7
2132c19:dd:ec00:c25:c25e:dd:ddca:dfa8/1272c19:dd:ec00:c25:c25e:dd:ddca:dfa9
2142c19:dd:ec00:c25:c25e:dd:ddca:dfaa/1272c19:dd:ec00:c25:c25e:dd:ddca:dfab
2152c19:dd:ec00:c25:c25e:dd:ddca:dfac/1272c19:dd:ec00:c25:c25e:dd:ddca:dfad
2162c19:dd:ec00:c25:c25e:dd:ddca:dfae/1272c19:dd:ec00:c25:c25e:dd:ddca:dfaf
2172c19:dd:ec00:c25:c25e:dd:ddca:dfb0/1272c19:dd:ec00:c25:c25e:dd:ddca:dfb1
2182c19:dd:ec00:c25:c25e:dd:ddca:dfb2/1272c19:dd:ec00:c25:c25e:dd:ddca:dfb3
2192c19:dd:ec00:c25:c25e:dd:ddca:dfb4/1272c19:dd:ec00:c25:c25e:dd:ddca:dfb5
2202c19:dd:ec00:c25:c25e:dd:ddca:dfb6/1272c19:dd:ec00:c25:c25e:dd:ddca:dfb7
2212c19:dd:ec00:c25:c25e:dd:ddca:dfb8/1272c19:dd:ec00:c25:c25e:dd:ddca:dfb9
2222c19:dd:ec00:c25:c25e:dd:ddca:dfba/1272c19:dd:ec00:c25:c25e:dd:ddca:dfbb
2232c19:dd:ec00:c25:c25e:dd:ddca:dfbc/1272c19:dd:ec00:c25:c25e:dd:ddca:dfbd
2242c19:dd:ec00:c25:c25e:dd:ddca:dfbe/1272c19:dd:ec00:c25:c25e:dd:ddca:dfbf
2252c19:dd:ec00:c25:c25e:dd:ddca:dfc0/1272c19:dd:ec00:c25:c25e:dd:ddca:dfc1
2262c19:dd:ec00:c25:c25e:dd:ddca:dfc2/1272c19:dd:ec00:c25:c25e:dd:ddca:dfc3
2272c19:dd:ec00:c25:c25e:dd:ddca:dfc4/1272c19:dd:ec00:c25:c25e:dd:ddca:dfc5
2282c19:dd:ec00:c25:c25e:dd:ddca:dfc6/1272c19:dd:ec00:c25:c25e:dd:ddca:dfc7
2292c19:dd:ec00:c25:c25e:dd:ddca:dfc8/1272c19:dd:ec00:c25:c25e:dd:ddca:dfc9
2302c19:dd:ec00:c25:c25e:dd:ddca:dfca/1272c19:dd:ec00:c25:c25e:dd:ddca:dfcb
2312c19:dd:ec00:c25:c25e:dd:ddca:dfcc/1272c19:dd:ec00:c25:c25e:dd:ddca:dfcd
2322c19:dd:ec00:c25:c25e:dd:ddca:dfce/1272c19:dd:ec00:c25:c25e:dd:ddca:dfcf
2332c19:dd:ec00:c25:c25e:dd:ddca:dfd0/1272c19:dd:ec00:c25:c25e:dd:ddca:dfd1
2342c19:dd:ec00:c25:c25e:dd:ddca:dfd2/1272c19:dd:ec00:c25:c25e:dd:ddca:dfd3
2352c19:dd:ec00:c25:c25e:dd:ddca:dfd4/1272c19:dd:ec00:c25:c25e:dd:ddca:dfd5
2362c19:dd:ec00:c25:c25e:dd:ddca:dfd6/1272c19:dd:ec00:c25:c25e:dd:ddca:dfd7
2372c19:dd:ec00:c25:c25e:dd:ddca:dfd8/1272c19:dd:ec00:c25:c25e:dd:ddca:dfd9
2382c19:dd:ec00:c25:c25e:dd:ddca:dfda/1272c19:dd:ec00:c25:c25e:dd:ddca:dfdb
2392c19:dd:ec00:c25:c25e:dd:ddca:dfdc/1272c19:dd:ec00:c25:c25e:dd:ddca:dfdd
2402c19:dd:ec00:c25:c25e:dd:ddca:dfde/1272c19:dd:ec00:c25:c25e:dd:ddca:dfdf
2412c19:dd:ec00:c25:c25e:dd:ddca:dfe0/1272c19:dd:ec00:c25:c25e:dd:ddca:dfe1
2422c19:dd:ec00:c25:c25e:dd:ddca:dfe2/1272c19:dd:ec00:c25:c25e:dd:ddca:dfe3
2432c19:dd:ec00:c25:c25e:dd:ddca:dfe4/1272c19:dd:ec00:c25:c25e:dd:ddca:dfe5
2442c19:dd:ec00:c25:c25e:dd:ddca:dfe6/1272c19:dd:ec00:c25:c25e:dd:ddca:dfe7
2452c19:dd:ec00:c25:c25e:dd:ddca:dfe8/1272c19:dd:ec00:c25:c25e:dd:ddca:dfe9
2462c19:dd:ec00:c25:c25e:dd:ddca:dfea/1272c19:dd:ec00:c25:c25e:dd:ddca:dfeb
2472c19:dd:ec00:c25:c25e:dd:ddca:dfec/1272c19:dd:ec00:c25:c25e:dd:ddca:dfed
2482c19:dd:ec00:c25:c25e:dd:ddca:dfee/1272c19:dd:ec00:c25:c25e:dd:ddca:dfef
2492c19:dd:ec00:c25:c25e:dd:ddca:dff0/1272c19:dd:ec00:c25:c25e:dd:ddca:dff1
2502c19:dd:ec00:c25:c25e:dd:ddca:dff2/1272c19:dd:ec00:c25:c25e:dd:ddca:dff3
2512c19:dd:ec00:c25:c25e:dd:ddca:dff4/1272c19:dd:ec00:c25:c25e:dd:ddca:dff5
2522c19:dd:ec00:c25:c25e:dd:ddca:dff6/1272c19:dd:ec00:c25:c25e:dd:ddca:dff7
2532c19:dd:ec00:c25:c25e:dd:ddca:dff8/1272c19:dd:ec00:c25:c25e:dd:ddca:dff9
2542c19:dd:ec00:c25:c25e:dd:ddca:dffa/1272c19:dd:ec00:c25:c25e:dd:ddca:dffb
2552c19:dd:ec00:c25:c25e:dd:ddca:dffc/1272c19:dd:ec00:c25:c25e:dd:ddca:dffd
2562c19:dd:ec00:c25:c25e:dd:ddca:dffe/1272c19:dd:ec00:c25:c25e:dd:ddca:dfff

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.