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:d915:da00/119
First address
2c19:dd:d9:dd:c25:c25:d915:da00
Last address
2c19:dd:d9:dd:c25:c25:d915:dbff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:d915:da00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
a.d.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
b.d.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
/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:d9:dd:c25:c25:d915:da00/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:d915:da00/1272c19:dd:d9:dd:c25:c25:d915:da01
22c19:dd:d9:dd:c25:c25:d915:da02/1272c19:dd:d9:dd:c25:c25:d915:da03
32c19:dd:d9:dd:c25:c25:d915:da04/1272c19:dd:d9:dd:c25:c25:d915:da05
42c19:dd:d9:dd:c25:c25:d915:da06/1272c19:dd:d9:dd:c25:c25:d915:da07
52c19:dd:d9:dd:c25:c25:d915:da08/1272c19:dd:d9:dd:c25:c25:d915:da09
62c19:dd:d9:dd:c25:c25:d915:da0a/1272c19:dd:d9:dd:c25:c25:d915:da0b
72c19:dd:d9:dd:c25:c25:d915:da0c/1272c19:dd:d9:dd:c25:c25:d915:da0d
82c19:dd:d9:dd:c25:c25:d915:da0e/1272c19:dd:d9:dd:c25:c25:d915:da0f
92c19:dd:d9:dd:c25:c25:d915:da10/1272c19:dd:d9:dd:c25:c25:d915:da11
102c19:dd:d9:dd:c25:c25:d915:da12/1272c19:dd:d9:dd:c25:c25:d915:da13
112c19:dd:d9:dd:c25:c25:d915:da14/1272c19:dd:d9:dd:c25:c25:d915:da15
122c19:dd:d9:dd:c25:c25:d915:da16/1272c19:dd:d9:dd:c25:c25:d915:da17
132c19:dd:d9:dd:c25:c25:d915:da18/1272c19:dd:d9:dd:c25:c25:d915:da19
142c19:dd:d9:dd:c25:c25:d915:da1a/1272c19:dd:d9:dd:c25:c25:d915:da1b
152c19:dd:d9:dd:c25:c25:d915:da1c/1272c19:dd:d9:dd:c25:c25:d915:da1d
162c19:dd:d9:dd:c25:c25:d915:da1e/1272c19:dd:d9:dd:c25:c25:d915:da1f
172c19:dd:d9:dd:c25:c25:d915:da20/1272c19:dd:d9:dd:c25:c25:d915:da21
182c19:dd:d9:dd:c25:c25:d915:da22/1272c19:dd:d9:dd:c25:c25:d915:da23
192c19:dd:d9:dd:c25:c25:d915:da24/1272c19:dd:d9:dd:c25:c25:d915:da25
202c19:dd:d9:dd:c25:c25:d915:da26/1272c19:dd:d9:dd:c25:c25:d915:da27
212c19:dd:d9:dd:c25:c25:d915:da28/1272c19:dd:d9:dd:c25:c25:d915:da29
222c19:dd:d9:dd:c25:c25:d915:da2a/1272c19:dd:d9:dd:c25:c25:d915:da2b
232c19:dd:d9:dd:c25:c25:d915:da2c/1272c19:dd:d9:dd:c25:c25:d915:da2d
242c19:dd:d9:dd:c25:c25:d915:da2e/1272c19:dd:d9:dd:c25:c25:d915:da2f
252c19:dd:d9:dd:c25:c25:d915:da30/1272c19:dd:d9:dd:c25:c25:d915:da31
262c19:dd:d9:dd:c25:c25:d915:da32/1272c19:dd:d9:dd:c25:c25:d915:da33
272c19:dd:d9:dd:c25:c25:d915:da34/1272c19:dd:d9:dd:c25:c25:d915:da35
282c19:dd:d9:dd:c25:c25:d915:da36/1272c19:dd:d9:dd:c25:c25:d915:da37
292c19:dd:d9:dd:c25:c25:d915:da38/1272c19:dd:d9:dd:c25:c25:d915:da39
302c19:dd:d9:dd:c25:c25:d915:da3a/1272c19:dd:d9:dd:c25:c25:d915:da3b
312c19:dd:d9:dd:c25:c25:d915:da3c/1272c19:dd:d9:dd:c25:c25:d915:da3d
322c19:dd:d9:dd:c25:c25:d915:da3e/1272c19:dd:d9:dd:c25:c25:d915:da3f
332c19:dd:d9:dd:c25:c25:d915:da40/1272c19:dd:d9:dd:c25:c25:d915:da41
342c19:dd:d9:dd:c25:c25:d915:da42/1272c19:dd:d9:dd:c25:c25:d915:da43
352c19:dd:d9:dd:c25:c25:d915:da44/1272c19:dd:d9:dd:c25:c25:d915:da45
362c19:dd:d9:dd:c25:c25:d915:da46/1272c19:dd:d9:dd:c25:c25:d915:da47
372c19:dd:d9:dd:c25:c25:d915:da48/1272c19:dd:d9:dd:c25:c25:d915:da49
382c19:dd:d9:dd:c25:c25:d915:da4a/1272c19:dd:d9:dd:c25:c25:d915:da4b
392c19:dd:d9:dd:c25:c25:d915:da4c/1272c19:dd:d9:dd:c25:c25:d915:da4d
402c19:dd:d9:dd:c25:c25:d915:da4e/1272c19:dd:d9:dd:c25:c25:d915:da4f
412c19:dd:d9:dd:c25:c25:d915:da50/1272c19:dd:d9:dd:c25:c25:d915:da51
422c19:dd:d9:dd:c25:c25:d915:da52/1272c19:dd:d9:dd:c25:c25:d915:da53
432c19:dd:d9:dd:c25:c25:d915:da54/1272c19:dd:d9:dd:c25:c25:d915:da55
442c19:dd:d9:dd:c25:c25:d915:da56/1272c19:dd:d9:dd:c25:c25:d915:da57
452c19:dd:d9:dd:c25:c25:d915:da58/1272c19:dd:d9:dd:c25:c25:d915:da59
462c19:dd:d9:dd:c25:c25:d915:da5a/1272c19:dd:d9:dd:c25:c25:d915:da5b
472c19:dd:d9:dd:c25:c25:d915:da5c/1272c19:dd:d9:dd:c25:c25:d915:da5d
482c19:dd:d9:dd:c25:c25:d915:da5e/1272c19:dd:d9:dd:c25:c25:d915:da5f
492c19:dd:d9:dd:c25:c25:d915:da60/1272c19:dd:d9:dd:c25:c25:d915:da61
502c19:dd:d9:dd:c25:c25:d915:da62/1272c19:dd:d9:dd:c25:c25:d915:da63
512c19:dd:d9:dd:c25:c25:d915:da64/1272c19:dd:d9:dd:c25:c25:d915:da65
522c19:dd:d9:dd:c25:c25:d915:da66/1272c19:dd:d9:dd:c25:c25:d915:da67
532c19:dd:d9:dd:c25:c25:d915:da68/1272c19:dd:d9:dd:c25:c25:d915:da69
542c19:dd:d9:dd:c25:c25:d915:da6a/1272c19:dd:d9:dd:c25:c25:d915:da6b
552c19:dd:d9:dd:c25:c25:d915:da6c/1272c19:dd:d9:dd:c25:c25:d915:da6d
562c19:dd:d9:dd:c25:c25:d915:da6e/1272c19:dd:d9:dd:c25:c25:d915:da6f
572c19:dd:d9:dd:c25:c25:d915:da70/1272c19:dd:d9:dd:c25:c25:d915:da71
582c19:dd:d9:dd:c25:c25:d915:da72/1272c19:dd:d9:dd:c25:c25:d915:da73
592c19:dd:d9:dd:c25:c25:d915:da74/1272c19:dd:d9:dd:c25:c25:d915:da75
602c19:dd:d9:dd:c25:c25:d915:da76/1272c19:dd:d9:dd:c25:c25:d915:da77
612c19:dd:d9:dd:c25:c25:d915:da78/1272c19:dd:d9:dd:c25:c25:d915:da79
622c19:dd:d9:dd:c25:c25:d915:da7a/1272c19:dd:d9:dd:c25:c25:d915:da7b
632c19:dd:d9:dd:c25:c25:d915:da7c/1272c19:dd:d9:dd:c25:c25:d915:da7d
642c19:dd:d9:dd:c25:c25:d915:da7e/1272c19:dd:d9:dd:c25:c25:d915:da7f
652c19:dd:d9:dd:c25:c25:d915:da80/1272c19:dd:d9:dd:c25:c25:d915:da81
662c19:dd:d9:dd:c25:c25:d915:da82/1272c19:dd:d9:dd:c25:c25:d915:da83
672c19:dd:d9:dd:c25:c25:d915:da84/1272c19:dd:d9:dd:c25:c25:d915:da85
682c19:dd:d9:dd:c25:c25:d915:da86/1272c19:dd:d9:dd:c25:c25:d915:da87
692c19:dd:d9:dd:c25:c25:d915:da88/1272c19:dd:d9:dd:c25:c25:d915:da89
702c19:dd:d9:dd:c25:c25:d915:da8a/1272c19:dd:d9:dd:c25:c25:d915:da8b
712c19:dd:d9:dd:c25:c25:d915:da8c/1272c19:dd:d9:dd:c25:c25:d915:da8d
722c19:dd:d9:dd:c25:c25:d915:da8e/1272c19:dd:d9:dd:c25:c25:d915:da8f
732c19:dd:d9:dd:c25:c25:d915:da90/1272c19:dd:d9:dd:c25:c25:d915:da91
742c19:dd:d9:dd:c25:c25:d915:da92/1272c19:dd:d9:dd:c25:c25:d915:da93
752c19:dd:d9:dd:c25:c25:d915:da94/1272c19:dd:d9:dd:c25:c25:d915:da95
762c19:dd:d9:dd:c25:c25:d915:da96/1272c19:dd:d9:dd:c25:c25:d915:da97
772c19:dd:d9:dd:c25:c25:d915:da98/1272c19:dd:d9:dd:c25:c25:d915:da99
782c19:dd:d9:dd:c25:c25:d915:da9a/1272c19:dd:d9:dd:c25:c25:d915:da9b
792c19:dd:d9:dd:c25:c25:d915:da9c/1272c19:dd:d9:dd:c25:c25:d915:da9d
802c19:dd:d9:dd:c25:c25:d915:da9e/1272c19:dd:d9:dd:c25:c25:d915:da9f
812c19:dd:d9:dd:c25:c25:d915:daa0/1272c19:dd:d9:dd:c25:c25:d915:daa1
822c19:dd:d9:dd:c25:c25:d915:daa2/1272c19:dd:d9:dd:c25:c25:d915:daa3
832c19:dd:d9:dd:c25:c25:d915:daa4/1272c19:dd:d9:dd:c25:c25:d915:daa5
842c19:dd:d9:dd:c25:c25:d915:daa6/1272c19:dd:d9:dd:c25:c25:d915:daa7
852c19:dd:d9:dd:c25:c25:d915:daa8/1272c19:dd:d9:dd:c25:c25:d915:daa9
862c19:dd:d9:dd:c25:c25:d915:daaa/1272c19:dd:d9:dd:c25:c25:d915:daab
872c19:dd:d9:dd:c25:c25:d915:daac/1272c19:dd:d9:dd:c25:c25:d915:daad
882c19:dd:d9:dd:c25:c25:d915:daae/1272c19:dd:d9:dd:c25:c25:d915:daaf
892c19:dd:d9:dd:c25:c25:d915:dab0/1272c19:dd:d9:dd:c25:c25:d915:dab1
902c19:dd:d9:dd:c25:c25:d915:dab2/1272c19:dd:d9:dd:c25:c25:d915:dab3
912c19:dd:d9:dd:c25:c25:d915:dab4/1272c19:dd:d9:dd:c25:c25:d915:dab5
922c19:dd:d9:dd:c25:c25:d915:dab6/1272c19:dd:d9:dd:c25:c25:d915:dab7
932c19:dd:d9:dd:c25:c25:d915:dab8/1272c19:dd:d9:dd:c25:c25:d915:dab9
942c19:dd:d9:dd:c25:c25:d915:daba/1272c19:dd:d9:dd:c25:c25:d915:dabb
952c19:dd:d9:dd:c25:c25:d915:dabc/1272c19:dd:d9:dd:c25:c25:d915:dabd
962c19:dd:d9:dd:c25:c25:d915:dabe/1272c19:dd:d9:dd:c25:c25:d915:dabf
972c19:dd:d9:dd:c25:c25:d915:dac0/1272c19:dd:d9:dd:c25:c25:d915:dac1
982c19:dd:d9:dd:c25:c25:d915:dac2/1272c19:dd:d9:dd:c25:c25:d915:dac3
992c19:dd:d9:dd:c25:c25:d915:dac4/1272c19:dd:d9:dd:c25:c25:d915:dac5
1002c19:dd:d9:dd:c25:c25:d915:dac6/1272c19:dd:d9:dd:c25:c25:d915:dac7
1012c19:dd:d9:dd:c25:c25:d915:dac8/1272c19:dd:d9:dd:c25:c25:d915:dac9
1022c19:dd:d9:dd:c25:c25:d915:daca/1272c19:dd:d9:dd:c25:c25:d915:dacb
1032c19:dd:d9:dd:c25:c25:d915:dacc/1272c19:dd:d9:dd:c25:c25:d915:dacd
1042c19:dd:d9:dd:c25:c25:d915:dace/1272c19:dd:d9:dd:c25:c25:d915:dacf
1052c19:dd:d9:dd:c25:c25:d915:dad0/1272c19:dd:d9:dd:c25:c25:d915:dad1
1062c19:dd:d9:dd:c25:c25:d915:dad2/1272c19:dd:d9:dd:c25:c25:d915:dad3
1072c19:dd:d9:dd:c25:c25:d915:dad4/1272c19:dd:d9:dd:c25:c25:d915:dad5
1082c19:dd:d9:dd:c25:c25:d915:dad6/1272c19:dd:d9:dd:c25:c25:d915:dad7
1092c19:dd:d9:dd:c25:c25:d915:dad8/1272c19:dd:d9:dd:c25:c25:d915:dad9
1102c19:dd:d9:dd:c25:c25:d915:dada/1272c19:dd:d9:dd:c25:c25:d915:dadb
1112c19:dd:d9:dd:c25:c25:d915:dadc/1272c19:dd:d9:dd:c25:c25:d915:dadd
1122c19:dd:d9:dd:c25:c25:d915:dade/1272c19:dd:d9:dd:c25:c25:d915:dadf
1132c19:dd:d9:dd:c25:c25:d915:dae0/1272c19:dd:d9:dd:c25:c25:d915:dae1
1142c19:dd:d9:dd:c25:c25:d915:dae2/1272c19:dd:d9:dd:c25:c25:d915:dae3
1152c19:dd:d9:dd:c25:c25:d915:dae4/1272c19:dd:d9:dd:c25:c25:d915:dae5
1162c19:dd:d9:dd:c25:c25:d915:dae6/1272c19:dd:d9:dd:c25:c25:d915:dae7
1172c19:dd:d9:dd:c25:c25:d915:dae8/1272c19:dd:d9:dd:c25:c25:d915:dae9
1182c19:dd:d9:dd:c25:c25:d915:daea/1272c19:dd:d9:dd:c25:c25:d915:daeb
1192c19:dd:d9:dd:c25:c25:d915:daec/1272c19:dd:d9:dd:c25:c25:d915:daed
1202c19:dd:d9:dd:c25:c25:d915:daee/1272c19:dd:d9:dd:c25:c25:d915:daef
1212c19:dd:d9:dd:c25:c25:d915:daf0/1272c19:dd:d9:dd:c25:c25:d915:daf1
1222c19:dd:d9:dd:c25:c25:d915:daf2/1272c19:dd:d9:dd:c25:c25:d915:daf3
1232c19:dd:d9:dd:c25:c25:d915:daf4/1272c19:dd:d9:dd:c25:c25:d915:daf5
1242c19:dd:d9:dd:c25:c25:d915:daf6/1272c19:dd:d9:dd:c25:c25:d915:daf7
1252c19:dd:d9:dd:c25:c25:d915:daf8/1272c19:dd:d9:dd:c25:c25:d915:daf9
1262c19:dd:d9:dd:c25:c25:d915:dafa/1272c19:dd:d9:dd:c25:c25:d915:dafb
1272c19:dd:d9:dd:c25:c25:d915:dafc/1272c19:dd:d9:dd:c25:c25:d915:dafd
1282c19:dd:d9:dd:c25:c25:d915:dafe/1272c19:dd:d9:dd:c25:c25:d915:daff
1292c19:dd:d9:dd:c25:c25:d915:db00/1272c19:dd:d9:dd:c25:c25:d915:db01
1302c19:dd:d9:dd:c25:c25:d915:db02/1272c19:dd:d9:dd:c25:c25:d915:db03
1312c19:dd:d9:dd:c25:c25:d915:db04/1272c19:dd:d9:dd:c25:c25:d915:db05
1322c19:dd:d9:dd:c25:c25:d915:db06/1272c19:dd:d9:dd:c25:c25:d915:db07
1332c19:dd:d9:dd:c25:c25:d915:db08/1272c19:dd:d9:dd:c25:c25:d915:db09
1342c19:dd:d9:dd:c25:c25:d915:db0a/1272c19:dd:d9:dd:c25:c25:d915:db0b
1352c19:dd:d9:dd:c25:c25:d915:db0c/1272c19:dd:d9:dd:c25:c25:d915:db0d
1362c19:dd:d9:dd:c25:c25:d915:db0e/1272c19:dd:d9:dd:c25:c25:d915:db0f
1372c19:dd:d9:dd:c25:c25:d915:db10/1272c19:dd:d9:dd:c25:c25:d915:db11
1382c19:dd:d9:dd:c25:c25:d915:db12/1272c19:dd:d9:dd:c25:c25:d915:db13
1392c19:dd:d9:dd:c25:c25:d915:db14/1272c19:dd:d9:dd:c25:c25:d915:db15
1402c19:dd:d9:dd:c25:c25:d915:db16/1272c19:dd:d9:dd:c25:c25:d915:db17
1412c19:dd:d9:dd:c25:c25:d915:db18/1272c19:dd:d9:dd:c25:c25:d915:db19
1422c19:dd:d9:dd:c25:c25:d915:db1a/1272c19:dd:d9:dd:c25:c25:d915:db1b
1432c19:dd:d9:dd:c25:c25:d915:db1c/1272c19:dd:d9:dd:c25:c25:d915:db1d
1442c19:dd:d9:dd:c25:c25:d915:db1e/1272c19:dd:d9:dd:c25:c25:d915:db1f
1452c19:dd:d9:dd:c25:c25:d915:db20/1272c19:dd:d9:dd:c25:c25:d915:db21
1462c19:dd:d9:dd:c25:c25:d915:db22/1272c19:dd:d9:dd:c25:c25:d915:db23
1472c19:dd:d9:dd:c25:c25:d915:db24/1272c19:dd:d9:dd:c25:c25:d915:db25
1482c19:dd:d9:dd:c25:c25:d915:db26/1272c19:dd:d9:dd:c25:c25:d915:db27
1492c19:dd:d9:dd:c25:c25:d915:db28/1272c19:dd:d9:dd:c25:c25:d915:db29
1502c19:dd:d9:dd:c25:c25:d915:db2a/1272c19:dd:d9:dd:c25:c25:d915:db2b
1512c19:dd:d9:dd:c25:c25:d915:db2c/1272c19:dd:d9:dd:c25:c25:d915:db2d
1522c19:dd:d9:dd:c25:c25:d915:db2e/1272c19:dd:d9:dd:c25:c25:d915:db2f
1532c19:dd:d9:dd:c25:c25:d915:db30/1272c19:dd:d9:dd:c25:c25:d915:db31
1542c19:dd:d9:dd:c25:c25:d915:db32/1272c19:dd:d9:dd:c25:c25:d915:db33
1552c19:dd:d9:dd:c25:c25:d915:db34/1272c19:dd:d9:dd:c25:c25:d915:db35
1562c19:dd:d9:dd:c25:c25:d915:db36/1272c19:dd:d9:dd:c25:c25:d915:db37
1572c19:dd:d9:dd:c25:c25:d915:db38/1272c19:dd:d9:dd:c25:c25:d915:db39
1582c19:dd:d9:dd:c25:c25:d915:db3a/1272c19:dd:d9:dd:c25:c25:d915:db3b
1592c19:dd:d9:dd:c25:c25:d915:db3c/1272c19:dd:d9:dd:c25:c25:d915:db3d
1602c19:dd:d9:dd:c25:c25:d915:db3e/1272c19:dd:d9:dd:c25:c25:d915:db3f
1612c19:dd:d9:dd:c25:c25:d915:db40/1272c19:dd:d9:dd:c25:c25:d915:db41
1622c19:dd:d9:dd:c25:c25:d915:db42/1272c19:dd:d9:dd:c25:c25:d915:db43
1632c19:dd:d9:dd:c25:c25:d915:db44/1272c19:dd:d9:dd:c25:c25:d915:db45
1642c19:dd:d9:dd:c25:c25:d915:db46/1272c19:dd:d9:dd:c25:c25:d915:db47
1652c19:dd:d9:dd:c25:c25:d915:db48/1272c19:dd:d9:dd:c25:c25:d915:db49
1662c19:dd:d9:dd:c25:c25:d915:db4a/1272c19:dd:d9:dd:c25:c25:d915:db4b
1672c19:dd:d9:dd:c25:c25:d915:db4c/1272c19:dd:d9:dd:c25:c25:d915:db4d
1682c19:dd:d9:dd:c25:c25:d915:db4e/1272c19:dd:d9:dd:c25:c25:d915:db4f
1692c19:dd:d9:dd:c25:c25:d915:db50/1272c19:dd:d9:dd:c25:c25:d915:db51
1702c19:dd:d9:dd:c25:c25:d915:db52/1272c19:dd:d9:dd:c25:c25:d915:db53
1712c19:dd:d9:dd:c25:c25:d915:db54/1272c19:dd:d9:dd:c25:c25:d915:db55
1722c19:dd:d9:dd:c25:c25:d915:db56/1272c19:dd:d9:dd:c25:c25:d915:db57
1732c19:dd:d9:dd:c25:c25:d915:db58/1272c19:dd:d9:dd:c25:c25:d915:db59
1742c19:dd:d9:dd:c25:c25:d915:db5a/1272c19:dd:d9:dd:c25:c25:d915:db5b
1752c19:dd:d9:dd:c25:c25:d915:db5c/1272c19:dd:d9:dd:c25:c25:d915:db5d
1762c19:dd:d9:dd:c25:c25:d915:db5e/1272c19:dd:d9:dd:c25:c25:d915:db5f
1772c19:dd:d9:dd:c25:c25:d915:db60/1272c19:dd:d9:dd:c25:c25:d915:db61
1782c19:dd:d9:dd:c25:c25:d915:db62/1272c19:dd:d9:dd:c25:c25:d915:db63
1792c19:dd:d9:dd:c25:c25:d915:db64/1272c19:dd:d9:dd:c25:c25:d915:db65
1802c19:dd:d9:dd:c25:c25:d915:db66/1272c19:dd:d9:dd:c25:c25:d915:db67
1812c19:dd:d9:dd:c25:c25:d915:db68/1272c19:dd:d9:dd:c25:c25:d915:db69
1822c19:dd:d9:dd:c25:c25:d915:db6a/1272c19:dd:d9:dd:c25:c25:d915:db6b
1832c19:dd:d9:dd:c25:c25:d915:db6c/1272c19:dd:d9:dd:c25:c25:d915:db6d
1842c19:dd:d9:dd:c25:c25:d915:db6e/1272c19:dd:d9:dd:c25:c25:d915:db6f
1852c19:dd:d9:dd:c25:c25:d915:db70/1272c19:dd:d9:dd:c25:c25:d915:db71
1862c19:dd:d9:dd:c25:c25:d915:db72/1272c19:dd:d9:dd:c25:c25:d915:db73
1872c19:dd:d9:dd:c25:c25:d915:db74/1272c19:dd:d9:dd:c25:c25:d915:db75
1882c19:dd:d9:dd:c25:c25:d915:db76/1272c19:dd:d9:dd:c25:c25:d915:db77
1892c19:dd:d9:dd:c25:c25:d915:db78/1272c19:dd:d9:dd:c25:c25:d915:db79
1902c19:dd:d9:dd:c25:c25:d915:db7a/1272c19:dd:d9:dd:c25:c25:d915:db7b
1912c19:dd:d9:dd:c25:c25:d915:db7c/1272c19:dd:d9:dd:c25:c25:d915:db7d
1922c19:dd:d9:dd:c25:c25:d915:db7e/1272c19:dd:d9:dd:c25:c25:d915:db7f
1932c19:dd:d9:dd:c25:c25:d915:db80/1272c19:dd:d9:dd:c25:c25:d915:db81
1942c19:dd:d9:dd:c25:c25:d915:db82/1272c19:dd:d9:dd:c25:c25:d915:db83
1952c19:dd:d9:dd:c25:c25:d915:db84/1272c19:dd:d9:dd:c25:c25:d915:db85
1962c19:dd:d9:dd:c25:c25:d915:db86/1272c19:dd:d9:dd:c25:c25:d915:db87
1972c19:dd:d9:dd:c25:c25:d915:db88/1272c19:dd:d9:dd:c25:c25:d915:db89
1982c19:dd:d9:dd:c25:c25:d915:db8a/1272c19:dd:d9:dd:c25:c25:d915:db8b
1992c19:dd:d9:dd:c25:c25:d915:db8c/1272c19:dd:d9:dd:c25:c25:d915:db8d
2002c19:dd:d9:dd:c25:c25:d915:db8e/1272c19:dd:d9:dd:c25:c25:d915:db8f
2012c19:dd:d9:dd:c25:c25:d915:db90/1272c19:dd:d9:dd:c25:c25:d915:db91
2022c19:dd:d9:dd:c25:c25:d915:db92/1272c19:dd:d9:dd:c25:c25:d915:db93
2032c19:dd:d9:dd:c25:c25:d915:db94/1272c19:dd:d9:dd:c25:c25:d915:db95
2042c19:dd:d9:dd:c25:c25:d915:db96/1272c19:dd:d9:dd:c25:c25:d915:db97
2052c19:dd:d9:dd:c25:c25:d915:db98/1272c19:dd:d9:dd:c25:c25:d915:db99
2062c19:dd:d9:dd:c25:c25:d915:db9a/1272c19:dd:d9:dd:c25:c25:d915:db9b
2072c19:dd:d9:dd:c25:c25:d915:db9c/1272c19:dd:d9:dd:c25:c25:d915:db9d
2082c19:dd:d9:dd:c25:c25:d915:db9e/1272c19:dd:d9:dd:c25:c25:d915:db9f
2092c19:dd:d9:dd:c25:c25:d915:dba0/1272c19:dd:d9:dd:c25:c25:d915:dba1
2102c19:dd:d9:dd:c25:c25:d915:dba2/1272c19:dd:d9:dd:c25:c25:d915:dba3
2112c19:dd:d9:dd:c25:c25:d915:dba4/1272c19:dd:d9:dd:c25:c25:d915:dba5
2122c19:dd:d9:dd:c25:c25:d915:dba6/1272c19:dd:d9:dd:c25:c25:d915:dba7
2132c19:dd:d9:dd:c25:c25:d915:dba8/1272c19:dd:d9:dd:c25:c25:d915:dba9
2142c19:dd:d9:dd:c25:c25:d915:dbaa/1272c19:dd:d9:dd:c25:c25:d915:dbab
2152c19:dd:d9:dd:c25:c25:d915:dbac/1272c19:dd:d9:dd:c25:c25:d915:dbad
2162c19:dd:d9:dd:c25:c25:d915:dbae/1272c19:dd:d9:dd:c25:c25:d915:dbaf
2172c19:dd:d9:dd:c25:c25:d915:dbb0/1272c19:dd:d9:dd:c25:c25:d915:dbb1
2182c19:dd:d9:dd:c25:c25:d915:dbb2/1272c19:dd:d9:dd:c25:c25:d915:dbb3
2192c19:dd:d9:dd:c25:c25:d915:dbb4/1272c19:dd:d9:dd:c25:c25:d915:dbb5
2202c19:dd:d9:dd:c25:c25:d915:dbb6/1272c19:dd:d9:dd:c25:c25:d915:dbb7
2212c19:dd:d9:dd:c25:c25:d915:dbb8/1272c19:dd:d9:dd:c25:c25:d915:dbb9
2222c19:dd:d9:dd:c25:c25:d915:dbba/1272c19:dd:d9:dd:c25:c25:d915:dbbb
2232c19:dd:d9:dd:c25:c25:d915:dbbc/1272c19:dd:d9:dd:c25:c25:d915:dbbd
2242c19:dd:d9:dd:c25:c25:d915:dbbe/1272c19:dd:d9:dd:c25:c25:d915:dbbf
2252c19:dd:d9:dd:c25:c25:d915:dbc0/1272c19:dd:d9:dd:c25:c25:d915:dbc1
2262c19:dd:d9:dd:c25:c25:d915:dbc2/1272c19:dd:d9:dd:c25:c25:d915:dbc3
2272c19:dd:d9:dd:c25:c25:d915:dbc4/1272c19:dd:d9:dd:c25:c25:d915:dbc5
2282c19:dd:d9:dd:c25:c25:d915:dbc6/1272c19:dd:d9:dd:c25:c25:d915:dbc7
2292c19:dd:d9:dd:c25:c25:d915:dbc8/1272c19:dd:d9:dd:c25:c25:d915:dbc9
2302c19:dd:d9:dd:c25:c25:d915:dbca/1272c19:dd:d9:dd:c25:c25:d915:dbcb
2312c19:dd:d9:dd:c25:c25:d915:dbcc/1272c19:dd:d9:dd:c25:c25:d915:dbcd
2322c19:dd:d9:dd:c25:c25:d915:dbce/1272c19:dd:d9:dd:c25:c25:d915:dbcf
2332c19:dd:d9:dd:c25:c25:d915:dbd0/1272c19:dd:d9:dd:c25:c25:d915:dbd1
2342c19:dd:d9:dd:c25:c25:d915:dbd2/1272c19:dd:d9:dd:c25:c25:d915:dbd3
2352c19:dd:d9:dd:c25:c25:d915:dbd4/1272c19:dd:d9:dd:c25:c25:d915:dbd5
2362c19:dd:d9:dd:c25:c25:d915:dbd6/1272c19:dd:d9:dd:c25:c25:d915:dbd7
2372c19:dd:d9:dd:c25:c25:d915:dbd8/1272c19:dd:d9:dd:c25:c25:d915:dbd9
2382c19:dd:d9:dd:c25:c25:d915:dbda/1272c19:dd:d9:dd:c25:c25:d915:dbdb
2392c19:dd:d9:dd:c25:c25:d915:dbdc/1272c19:dd:d9:dd:c25:c25:d915:dbdd
2402c19:dd:d9:dd:c25:c25:d915:dbde/1272c19:dd:d9:dd:c25:c25:d915:dbdf
2412c19:dd:d9:dd:c25:c25:d915:dbe0/1272c19:dd:d9:dd:c25:c25:d915:dbe1
2422c19:dd:d9:dd:c25:c25:d915:dbe2/1272c19:dd:d9:dd:c25:c25:d915:dbe3
2432c19:dd:d9:dd:c25:c25:d915:dbe4/1272c19:dd:d9:dd:c25:c25:d915:dbe5
2442c19:dd:d9:dd:c25:c25:d915:dbe6/1272c19:dd:d9:dd:c25:c25:d915:dbe7
2452c19:dd:d9:dd:c25:c25:d915:dbe8/1272c19:dd:d9:dd:c25:c25:d915:dbe9
2462c19:dd:d9:dd:c25:c25:d915:dbea/1272c19:dd:d9:dd:c25:c25:d915:dbeb
2472c19:dd:d9:dd:c25:c25:d915:dbec/1272c19:dd:d9:dd:c25:c25:d915:dbed
2482c19:dd:d9:dd:c25:c25:d915:dbee/1272c19:dd:d9:dd:c25:c25:d915:dbef
2492c19:dd:d9:dd:c25:c25:d915:dbf0/1272c19:dd:d9:dd:c25:c25:d915:dbf1
2502c19:dd:d9:dd:c25:c25:d915:dbf2/1272c19:dd:d9:dd:c25:c25:d915:dbf3
2512c19:dd:d9:dd:c25:c25:d915:dbf4/1272c19:dd:d9:dd:c25:c25:d915:dbf5
2522c19:dd:d9:dd:c25:c25:d915:dbf6/1272c19:dd:d9:dd:c25:c25:d915:dbf7
2532c19:dd:d9:dd:c25:c25:d915:dbf8/1272c19:dd:d9:dd:c25:c25:d915:dbf9
2542c19:dd:d9:dd:c25:c25:d915:dbfa/1272c19:dd:d9:dd:c25:c25:d915:dbfb
2552c19:dd:d9:dd:c25:c25:d915:dbfc/1272c19:dd:d9:dd:c25:c25:d915:dbfd
2562c19:dd:d9:dd:c25:c25:d915:dbfe/1272c19:dd:d9:dd:c25:c25:d915:dbff

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.