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:a003:ec00/119
First address
2c19:dd:d9:dd:c25:c25:a003:ec00
Last address
2c19:dd:d9:dd:c25:c25:a003:edff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:a003:ec00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
c.e.3.0.0.a.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.e.3.0.0.a.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:a003:ec00/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:a003:ec00/1272c19:dd:d9:dd:c25:c25:a003:ec01
22c19:dd:d9:dd:c25:c25:a003:ec02/1272c19:dd:d9:dd:c25:c25:a003:ec03
32c19:dd:d9:dd:c25:c25:a003:ec04/1272c19:dd:d9:dd:c25:c25:a003:ec05
42c19:dd:d9:dd:c25:c25:a003:ec06/1272c19:dd:d9:dd:c25:c25:a003:ec07
52c19:dd:d9:dd:c25:c25:a003:ec08/1272c19:dd:d9:dd:c25:c25:a003:ec09
62c19:dd:d9:dd:c25:c25:a003:ec0a/1272c19:dd:d9:dd:c25:c25:a003:ec0b
72c19:dd:d9:dd:c25:c25:a003:ec0c/1272c19:dd:d9:dd:c25:c25:a003:ec0d
82c19:dd:d9:dd:c25:c25:a003:ec0e/1272c19:dd:d9:dd:c25:c25:a003:ec0f
92c19:dd:d9:dd:c25:c25:a003:ec10/1272c19:dd:d9:dd:c25:c25:a003:ec11
102c19:dd:d9:dd:c25:c25:a003:ec12/1272c19:dd:d9:dd:c25:c25:a003:ec13
112c19:dd:d9:dd:c25:c25:a003:ec14/1272c19:dd:d9:dd:c25:c25:a003:ec15
122c19:dd:d9:dd:c25:c25:a003:ec16/1272c19:dd:d9:dd:c25:c25:a003:ec17
132c19:dd:d9:dd:c25:c25:a003:ec18/1272c19:dd:d9:dd:c25:c25:a003:ec19
142c19:dd:d9:dd:c25:c25:a003:ec1a/1272c19:dd:d9:dd:c25:c25:a003:ec1b
152c19:dd:d9:dd:c25:c25:a003:ec1c/1272c19:dd:d9:dd:c25:c25:a003:ec1d
162c19:dd:d9:dd:c25:c25:a003:ec1e/1272c19:dd:d9:dd:c25:c25:a003:ec1f
172c19:dd:d9:dd:c25:c25:a003:ec20/1272c19:dd:d9:dd:c25:c25:a003:ec21
182c19:dd:d9:dd:c25:c25:a003:ec22/1272c19:dd:d9:dd:c25:c25:a003:ec23
192c19:dd:d9:dd:c25:c25:a003:ec24/1272c19:dd:d9:dd:c25:c25:a003:ec25
202c19:dd:d9:dd:c25:c25:a003:ec26/1272c19:dd:d9:dd:c25:c25:a003:ec27
212c19:dd:d9:dd:c25:c25:a003:ec28/1272c19:dd:d9:dd:c25:c25:a003:ec29
222c19:dd:d9:dd:c25:c25:a003:ec2a/1272c19:dd:d9:dd:c25:c25:a003:ec2b
232c19:dd:d9:dd:c25:c25:a003:ec2c/1272c19:dd:d9:dd:c25:c25:a003:ec2d
242c19:dd:d9:dd:c25:c25:a003:ec2e/1272c19:dd:d9:dd:c25:c25:a003:ec2f
252c19:dd:d9:dd:c25:c25:a003:ec30/1272c19:dd:d9:dd:c25:c25:a003:ec31
262c19:dd:d9:dd:c25:c25:a003:ec32/1272c19:dd:d9:dd:c25:c25:a003:ec33
272c19:dd:d9:dd:c25:c25:a003:ec34/1272c19:dd:d9:dd:c25:c25:a003:ec35
282c19:dd:d9:dd:c25:c25:a003:ec36/1272c19:dd:d9:dd:c25:c25:a003:ec37
292c19:dd:d9:dd:c25:c25:a003:ec38/1272c19:dd:d9:dd:c25:c25:a003:ec39
302c19:dd:d9:dd:c25:c25:a003:ec3a/1272c19:dd:d9:dd:c25:c25:a003:ec3b
312c19:dd:d9:dd:c25:c25:a003:ec3c/1272c19:dd:d9:dd:c25:c25:a003:ec3d
322c19:dd:d9:dd:c25:c25:a003:ec3e/1272c19:dd:d9:dd:c25:c25:a003:ec3f
332c19:dd:d9:dd:c25:c25:a003:ec40/1272c19:dd:d9:dd:c25:c25:a003:ec41
342c19:dd:d9:dd:c25:c25:a003:ec42/1272c19:dd:d9:dd:c25:c25:a003:ec43
352c19:dd:d9:dd:c25:c25:a003:ec44/1272c19:dd:d9:dd:c25:c25:a003:ec45
362c19:dd:d9:dd:c25:c25:a003:ec46/1272c19:dd:d9:dd:c25:c25:a003:ec47
372c19:dd:d9:dd:c25:c25:a003:ec48/1272c19:dd:d9:dd:c25:c25:a003:ec49
382c19:dd:d9:dd:c25:c25:a003:ec4a/1272c19:dd:d9:dd:c25:c25:a003:ec4b
392c19:dd:d9:dd:c25:c25:a003:ec4c/1272c19:dd:d9:dd:c25:c25:a003:ec4d
402c19:dd:d9:dd:c25:c25:a003:ec4e/1272c19:dd:d9:dd:c25:c25:a003:ec4f
412c19:dd:d9:dd:c25:c25:a003:ec50/1272c19:dd:d9:dd:c25:c25:a003:ec51
422c19:dd:d9:dd:c25:c25:a003:ec52/1272c19:dd:d9:dd:c25:c25:a003:ec53
432c19:dd:d9:dd:c25:c25:a003:ec54/1272c19:dd:d9:dd:c25:c25:a003:ec55
442c19:dd:d9:dd:c25:c25:a003:ec56/1272c19:dd:d9:dd:c25:c25:a003:ec57
452c19:dd:d9:dd:c25:c25:a003:ec58/1272c19:dd:d9:dd:c25:c25:a003:ec59
462c19:dd:d9:dd:c25:c25:a003:ec5a/1272c19:dd:d9:dd:c25:c25:a003:ec5b
472c19:dd:d9:dd:c25:c25:a003:ec5c/1272c19:dd:d9:dd:c25:c25:a003:ec5d
482c19:dd:d9:dd:c25:c25:a003:ec5e/1272c19:dd:d9:dd:c25:c25:a003:ec5f
492c19:dd:d9:dd:c25:c25:a003:ec60/1272c19:dd:d9:dd:c25:c25:a003:ec61
502c19:dd:d9:dd:c25:c25:a003:ec62/1272c19:dd:d9:dd:c25:c25:a003:ec63
512c19:dd:d9:dd:c25:c25:a003:ec64/1272c19:dd:d9:dd:c25:c25:a003:ec65
522c19:dd:d9:dd:c25:c25:a003:ec66/1272c19:dd:d9:dd:c25:c25:a003:ec67
532c19:dd:d9:dd:c25:c25:a003:ec68/1272c19:dd:d9:dd:c25:c25:a003:ec69
542c19:dd:d9:dd:c25:c25:a003:ec6a/1272c19:dd:d9:dd:c25:c25:a003:ec6b
552c19:dd:d9:dd:c25:c25:a003:ec6c/1272c19:dd:d9:dd:c25:c25:a003:ec6d
562c19:dd:d9:dd:c25:c25:a003:ec6e/1272c19:dd:d9:dd:c25:c25:a003:ec6f
572c19:dd:d9:dd:c25:c25:a003:ec70/1272c19:dd:d9:dd:c25:c25:a003:ec71
582c19:dd:d9:dd:c25:c25:a003:ec72/1272c19:dd:d9:dd:c25:c25:a003:ec73
592c19:dd:d9:dd:c25:c25:a003:ec74/1272c19:dd:d9:dd:c25:c25:a003:ec75
602c19:dd:d9:dd:c25:c25:a003:ec76/1272c19:dd:d9:dd:c25:c25:a003:ec77
612c19:dd:d9:dd:c25:c25:a003:ec78/1272c19:dd:d9:dd:c25:c25:a003:ec79
622c19:dd:d9:dd:c25:c25:a003:ec7a/1272c19:dd:d9:dd:c25:c25:a003:ec7b
632c19:dd:d9:dd:c25:c25:a003:ec7c/1272c19:dd:d9:dd:c25:c25:a003:ec7d
642c19:dd:d9:dd:c25:c25:a003:ec7e/1272c19:dd:d9:dd:c25:c25:a003:ec7f
652c19:dd:d9:dd:c25:c25:a003:ec80/1272c19:dd:d9:dd:c25:c25:a003:ec81
662c19:dd:d9:dd:c25:c25:a003:ec82/1272c19:dd:d9:dd:c25:c25:a003:ec83
672c19:dd:d9:dd:c25:c25:a003:ec84/1272c19:dd:d9:dd:c25:c25:a003:ec85
682c19:dd:d9:dd:c25:c25:a003:ec86/1272c19:dd:d9:dd:c25:c25:a003:ec87
692c19:dd:d9:dd:c25:c25:a003:ec88/1272c19:dd:d9:dd:c25:c25:a003:ec89
702c19:dd:d9:dd:c25:c25:a003:ec8a/1272c19:dd:d9:dd:c25:c25:a003:ec8b
712c19:dd:d9:dd:c25:c25:a003:ec8c/1272c19:dd:d9:dd:c25:c25:a003:ec8d
722c19:dd:d9:dd:c25:c25:a003:ec8e/1272c19:dd:d9:dd:c25:c25:a003:ec8f
732c19:dd:d9:dd:c25:c25:a003:ec90/1272c19:dd:d9:dd:c25:c25:a003:ec91
742c19:dd:d9:dd:c25:c25:a003:ec92/1272c19:dd:d9:dd:c25:c25:a003:ec93
752c19:dd:d9:dd:c25:c25:a003:ec94/1272c19:dd:d9:dd:c25:c25:a003:ec95
762c19:dd:d9:dd:c25:c25:a003:ec96/1272c19:dd:d9:dd:c25:c25:a003:ec97
772c19:dd:d9:dd:c25:c25:a003:ec98/1272c19:dd:d9:dd:c25:c25:a003:ec99
782c19:dd:d9:dd:c25:c25:a003:ec9a/1272c19:dd:d9:dd:c25:c25:a003:ec9b
792c19:dd:d9:dd:c25:c25:a003:ec9c/1272c19:dd:d9:dd:c25:c25:a003:ec9d
802c19:dd:d9:dd:c25:c25:a003:ec9e/1272c19:dd:d9:dd:c25:c25:a003:ec9f
812c19:dd:d9:dd:c25:c25:a003:eca0/1272c19:dd:d9:dd:c25:c25:a003:eca1
822c19:dd:d9:dd:c25:c25:a003:eca2/1272c19:dd:d9:dd:c25:c25:a003:eca3
832c19:dd:d9:dd:c25:c25:a003:eca4/1272c19:dd:d9:dd:c25:c25:a003:eca5
842c19:dd:d9:dd:c25:c25:a003:eca6/1272c19:dd:d9:dd:c25:c25:a003:eca7
852c19:dd:d9:dd:c25:c25:a003:eca8/1272c19:dd:d9:dd:c25:c25:a003:eca9
862c19:dd:d9:dd:c25:c25:a003:ecaa/1272c19:dd:d9:dd:c25:c25:a003:ecab
872c19:dd:d9:dd:c25:c25:a003:ecac/1272c19:dd:d9:dd:c25:c25:a003:ecad
882c19:dd:d9:dd:c25:c25:a003:ecae/1272c19:dd:d9:dd:c25:c25:a003:ecaf
892c19:dd:d9:dd:c25:c25:a003:ecb0/1272c19:dd:d9:dd:c25:c25:a003:ecb1
902c19:dd:d9:dd:c25:c25:a003:ecb2/1272c19:dd:d9:dd:c25:c25:a003:ecb3
912c19:dd:d9:dd:c25:c25:a003:ecb4/1272c19:dd:d9:dd:c25:c25:a003:ecb5
922c19:dd:d9:dd:c25:c25:a003:ecb6/1272c19:dd:d9:dd:c25:c25:a003:ecb7
932c19:dd:d9:dd:c25:c25:a003:ecb8/1272c19:dd:d9:dd:c25:c25:a003:ecb9
942c19:dd:d9:dd:c25:c25:a003:ecba/1272c19:dd:d9:dd:c25:c25:a003:ecbb
952c19:dd:d9:dd:c25:c25:a003:ecbc/1272c19:dd:d9:dd:c25:c25:a003:ecbd
962c19:dd:d9:dd:c25:c25:a003:ecbe/1272c19:dd:d9:dd:c25:c25:a003:ecbf
972c19:dd:d9:dd:c25:c25:a003:ecc0/1272c19:dd:d9:dd:c25:c25:a003:ecc1
982c19:dd:d9:dd:c25:c25:a003:ecc2/1272c19:dd:d9:dd:c25:c25:a003:ecc3
992c19:dd:d9:dd:c25:c25:a003:ecc4/1272c19:dd:d9:dd:c25:c25:a003:ecc5
1002c19:dd:d9:dd:c25:c25:a003:ecc6/1272c19:dd:d9:dd:c25:c25:a003:ecc7
1012c19:dd:d9:dd:c25:c25:a003:ecc8/1272c19:dd:d9:dd:c25:c25:a003:ecc9
1022c19:dd:d9:dd:c25:c25:a003:ecca/1272c19:dd:d9:dd:c25:c25:a003:eccb
1032c19:dd:d9:dd:c25:c25:a003:eccc/1272c19:dd:d9:dd:c25:c25:a003:eccd
1042c19:dd:d9:dd:c25:c25:a003:ecce/1272c19:dd:d9:dd:c25:c25:a003:eccf
1052c19:dd:d9:dd:c25:c25:a003:ecd0/1272c19:dd:d9:dd:c25:c25:a003:ecd1
1062c19:dd:d9:dd:c25:c25:a003:ecd2/1272c19:dd:d9:dd:c25:c25:a003:ecd3
1072c19:dd:d9:dd:c25:c25:a003:ecd4/1272c19:dd:d9:dd:c25:c25:a003:ecd5
1082c19:dd:d9:dd:c25:c25:a003:ecd6/1272c19:dd:d9:dd:c25:c25:a003:ecd7
1092c19:dd:d9:dd:c25:c25:a003:ecd8/1272c19:dd:d9:dd:c25:c25:a003:ecd9
1102c19:dd:d9:dd:c25:c25:a003:ecda/1272c19:dd:d9:dd:c25:c25:a003:ecdb
1112c19:dd:d9:dd:c25:c25:a003:ecdc/1272c19:dd:d9:dd:c25:c25:a003:ecdd
1122c19:dd:d9:dd:c25:c25:a003:ecde/1272c19:dd:d9:dd:c25:c25:a003:ecdf
1132c19:dd:d9:dd:c25:c25:a003:ece0/1272c19:dd:d9:dd:c25:c25:a003:ece1
1142c19:dd:d9:dd:c25:c25:a003:ece2/1272c19:dd:d9:dd:c25:c25:a003:ece3
1152c19:dd:d9:dd:c25:c25:a003:ece4/1272c19:dd:d9:dd:c25:c25:a003:ece5
1162c19:dd:d9:dd:c25:c25:a003:ece6/1272c19:dd:d9:dd:c25:c25:a003:ece7
1172c19:dd:d9:dd:c25:c25:a003:ece8/1272c19:dd:d9:dd:c25:c25:a003:ece9
1182c19:dd:d9:dd:c25:c25:a003:ecea/1272c19:dd:d9:dd:c25:c25:a003:eceb
1192c19:dd:d9:dd:c25:c25:a003:ecec/1272c19:dd:d9:dd:c25:c25:a003:eced
1202c19:dd:d9:dd:c25:c25:a003:ecee/1272c19:dd:d9:dd:c25:c25:a003:ecef
1212c19:dd:d9:dd:c25:c25:a003:ecf0/1272c19:dd:d9:dd:c25:c25:a003:ecf1
1222c19:dd:d9:dd:c25:c25:a003:ecf2/1272c19:dd:d9:dd:c25:c25:a003:ecf3
1232c19:dd:d9:dd:c25:c25:a003:ecf4/1272c19:dd:d9:dd:c25:c25:a003:ecf5
1242c19:dd:d9:dd:c25:c25:a003:ecf6/1272c19:dd:d9:dd:c25:c25:a003:ecf7
1252c19:dd:d9:dd:c25:c25:a003:ecf8/1272c19:dd:d9:dd:c25:c25:a003:ecf9
1262c19:dd:d9:dd:c25:c25:a003:ecfa/1272c19:dd:d9:dd:c25:c25:a003:ecfb
1272c19:dd:d9:dd:c25:c25:a003:ecfc/1272c19:dd:d9:dd:c25:c25:a003:ecfd
1282c19:dd:d9:dd:c25:c25:a003:ecfe/1272c19:dd:d9:dd:c25:c25:a003:ecff
1292c19:dd:d9:dd:c25:c25:a003:ed00/1272c19:dd:d9:dd:c25:c25:a003:ed01
1302c19:dd:d9:dd:c25:c25:a003:ed02/1272c19:dd:d9:dd:c25:c25:a003:ed03
1312c19:dd:d9:dd:c25:c25:a003:ed04/1272c19:dd:d9:dd:c25:c25:a003:ed05
1322c19:dd:d9:dd:c25:c25:a003:ed06/1272c19:dd:d9:dd:c25:c25:a003:ed07
1332c19:dd:d9:dd:c25:c25:a003:ed08/1272c19:dd:d9:dd:c25:c25:a003:ed09
1342c19:dd:d9:dd:c25:c25:a003:ed0a/1272c19:dd:d9:dd:c25:c25:a003:ed0b
1352c19:dd:d9:dd:c25:c25:a003:ed0c/1272c19:dd:d9:dd:c25:c25:a003:ed0d
1362c19:dd:d9:dd:c25:c25:a003:ed0e/1272c19:dd:d9:dd:c25:c25:a003:ed0f
1372c19:dd:d9:dd:c25:c25:a003:ed10/1272c19:dd:d9:dd:c25:c25:a003:ed11
1382c19:dd:d9:dd:c25:c25:a003:ed12/1272c19:dd:d9:dd:c25:c25:a003:ed13
1392c19:dd:d9:dd:c25:c25:a003:ed14/1272c19:dd:d9:dd:c25:c25:a003:ed15
1402c19:dd:d9:dd:c25:c25:a003:ed16/1272c19:dd:d9:dd:c25:c25:a003:ed17
1412c19:dd:d9:dd:c25:c25:a003:ed18/1272c19:dd:d9:dd:c25:c25:a003:ed19
1422c19:dd:d9:dd:c25:c25:a003:ed1a/1272c19:dd:d9:dd:c25:c25:a003:ed1b
1432c19:dd:d9:dd:c25:c25:a003:ed1c/1272c19:dd:d9:dd:c25:c25:a003:ed1d
1442c19:dd:d9:dd:c25:c25:a003:ed1e/1272c19:dd:d9:dd:c25:c25:a003:ed1f
1452c19:dd:d9:dd:c25:c25:a003:ed20/1272c19:dd:d9:dd:c25:c25:a003:ed21
1462c19:dd:d9:dd:c25:c25:a003:ed22/1272c19:dd:d9:dd:c25:c25:a003:ed23
1472c19:dd:d9:dd:c25:c25:a003:ed24/1272c19:dd:d9:dd:c25:c25:a003:ed25
1482c19:dd:d9:dd:c25:c25:a003:ed26/1272c19:dd:d9:dd:c25:c25:a003:ed27
1492c19:dd:d9:dd:c25:c25:a003:ed28/1272c19:dd:d9:dd:c25:c25:a003:ed29
1502c19:dd:d9:dd:c25:c25:a003:ed2a/1272c19:dd:d9:dd:c25:c25:a003:ed2b
1512c19:dd:d9:dd:c25:c25:a003:ed2c/1272c19:dd:d9:dd:c25:c25:a003:ed2d
1522c19:dd:d9:dd:c25:c25:a003:ed2e/1272c19:dd:d9:dd:c25:c25:a003:ed2f
1532c19:dd:d9:dd:c25:c25:a003:ed30/1272c19:dd:d9:dd:c25:c25:a003:ed31
1542c19:dd:d9:dd:c25:c25:a003:ed32/1272c19:dd:d9:dd:c25:c25:a003:ed33
1552c19:dd:d9:dd:c25:c25:a003:ed34/1272c19:dd:d9:dd:c25:c25:a003:ed35
1562c19:dd:d9:dd:c25:c25:a003:ed36/1272c19:dd:d9:dd:c25:c25:a003:ed37
1572c19:dd:d9:dd:c25:c25:a003:ed38/1272c19:dd:d9:dd:c25:c25:a003:ed39
1582c19:dd:d9:dd:c25:c25:a003:ed3a/1272c19:dd:d9:dd:c25:c25:a003:ed3b
1592c19:dd:d9:dd:c25:c25:a003:ed3c/1272c19:dd:d9:dd:c25:c25:a003:ed3d
1602c19:dd:d9:dd:c25:c25:a003:ed3e/1272c19:dd:d9:dd:c25:c25:a003:ed3f
1612c19:dd:d9:dd:c25:c25:a003:ed40/1272c19:dd:d9:dd:c25:c25:a003:ed41
1622c19:dd:d9:dd:c25:c25:a003:ed42/1272c19:dd:d9:dd:c25:c25:a003:ed43
1632c19:dd:d9:dd:c25:c25:a003:ed44/1272c19:dd:d9:dd:c25:c25:a003:ed45
1642c19:dd:d9:dd:c25:c25:a003:ed46/1272c19:dd:d9:dd:c25:c25:a003:ed47
1652c19:dd:d9:dd:c25:c25:a003:ed48/1272c19:dd:d9:dd:c25:c25:a003:ed49
1662c19:dd:d9:dd:c25:c25:a003:ed4a/1272c19:dd:d9:dd:c25:c25:a003:ed4b
1672c19:dd:d9:dd:c25:c25:a003:ed4c/1272c19:dd:d9:dd:c25:c25:a003:ed4d
1682c19:dd:d9:dd:c25:c25:a003:ed4e/1272c19:dd:d9:dd:c25:c25:a003:ed4f
1692c19:dd:d9:dd:c25:c25:a003:ed50/1272c19:dd:d9:dd:c25:c25:a003:ed51
1702c19:dd:d9:dd:c25:c25:a003:ed52/1272c19:dd:d9:dd:c25:c25:a003:ed53
1712c19:dd:d9:dd:c25:c25:a003:ed54/1272c19:dd:d9:dd:c25:c25:a003:ed55
1722c19:dd:d9:dd:c25:c25:a003:ed56/1272c19:dd:d9:dd:c25:c25:a003:ed57
1732c19:dd:d9:dd:c25:c25:a003:ed58/1272c19:dd:d9:dd:c25:c25:a003:ed59
1742c19:dd:d9:dd:c25:c25:a003:ed5a/1272c19:dd:d9:dd:c25:c25:a003:ed5b
1752c19:dd:d9:dd:c25:c25:a003:ed5c/1272c19:dd:d9:dd:c25:c25:a003:ed5d
1762c19:dd:d9:dd:c25:c25:a003:ed5e/1272c19:dd:d9:dd:c25:c25:a003:ed5f
1772c19:dd:d9:dd:c25:c25:a003:ed60/1272c19:dd:d9:dd:c25:c25:a003:ed61
1782c19:dd:d9:dd:c25:c25:a003:ed62/1272c19:dd:d9:dd:c25:c25:a003:ed63
1792c19:dd:d9:dd:c25:c25:a003:ed64/1272c19:dd:d9:dd:c25:c25:a003:ed65
1802c19:dd:d9:dd:c25:c25:a003:ed66/1272c19:dd:d9:dd:c25:c25:a003:ed67
1812c19:dd:d9:dd:c25:c25:a003:ed68/1272c19:dd:d9:dd:c25:c25:a003:ed69
1822c19:dd:d9:dd:c25:c25:a003:ed6a/1272c19:dd:d9:dd:c25:c25:a003:ed6b
1832c19:dd:d9:dd:c25:c25:a003:ed6c/1272c19:dd:d9:dd:c25:c25:a003:ed6d
1842c19:dd:d9:dd:c25:c25:a003:ed6e/1272c19:dd:d9:dd:c25:c25:a003:ed6f
1852c19:dd:d9:dd:c25:c25:a003:ed70/1272c19:dd:d9:dd:c25:c25:a003:ed71
1862c19:dd:d9:dd:c25:c25:a003:ed72/1272c19:dd:d9:dd:c25:c25:a003:ed73
1872c19:dd:d9:dd:c25:c25:a003:ed74/1272c19:dd:d9:dd:c25:c25:a003:ed75
1882c19:dd:d9:dd:c25:c25:a003:ed76/1272c19:dd:d9:dd:c25:c25:a003:ed77
1892c19:dd:d9:dd:c25:c25:a003:ed78/1272c19:dd:d9:dd:c25:c25:a003:ed79
1902c19:dd:d9:dd:c25:c25:a003:ed7a/1272c19:dd:d9:dd:c25:c25:a003:ed7b
1912c19:dd:d9:dd:c25:c25:a003:ed7c/1272c19:dd:d9:dd:c25:c25:a003:ed7d
1922c19:dd:d9:dd:c25:c25:a003:ed7e/1272c19:dd:d9:dd:c25:c25:a003:ed7f
1932c19:dd:d9:dd:c25:c25:a003:ed80/1272c19:dd:d9:dd:c25:c25:a003:ed81
1942c19:dd:d9:dd:c25:c25:a003:ed82/1272c19:dd:d9:dd:c25:c25:a003:ed83
1952c19:dd:d9:dd:c25:c25:a003:ed84/1272c19:dd:d9:dd:c25:c25:a003:ed85
1962c19:dd:d9:dd:c25:c25:a003:ed86/1272c19:dd:d9:dd:c25:c25:a003:ed87
1972c19:dd:d9:dd:c25:c25:a003:ed88/1272c19:dd:d9:dd:c25:c25:a003:ed89
1982c19:dd:d9:dd:c25:c25:a003:ed8a/1272c19:dd:d9:dd:c25:c25:a003:ed8b
1992c19:dd:d9:dd:c25:c25:a003:ed8c/1272c19:dd:d9:dd:c25:c25:a003:ed8d
2002c19:dd:d9:dd:c25:c25:a003:ed8e/1272c19:dd:d9:dd:c25:c25:a003:ed8f
2012c19:dd:d9:dd:c25:c25:a003:ed90/1272c19:dd:d9:dd:c25:c25:a003:ed91
2022c19:dd:d9:dd:c25:c25:a003:ed92/1272c19:dd:d9:dd:c25:c25:a003:ed93
2032c19:dd:d9:dd:c25:c25:a003:ed94/1272c19:dd:d9:dd:c25:c25:a003:ed95
2042c19:dd:d9:dd:c25:c25:a003:ed96/1272c19:dd:d9:dd:c25:c25:a003:ed97
2052c19:dd:d9:dd:c25:c25:a003:ed98/1272c19:dd:d9:dd:c25:c25:a003:ed99
2062c19:dd:d9:dd:c25:c25:a003:ed9a/1272c19:dd:d9:dd:c25:c25:a003:ed9b
2072c19:dd:d9:dd:c25:c25:a003:ed9c/1272c19:dd:d9:dd:c25:c25:a003:ed9d
2082c19:dd:d9:dd:c25:c25:a003:ed9e/1272c19:dd:d9:dd:c25:c25:a003:ed9f
2092c19:dd:d9:dd:c25:c25:a003:eda0/1272c19:dd:d9:dd:c25:c25:a003:eda1
2102c19:dd:d9:dd:c25:c25:a003:eda2/1272c19:dd:d9:dd:c25:c25:a003:eda3
2112c19:dd:d9:dd:c25:c25:a003:eda4/1272c19:dd:d9:dd:c25:c25:a003:eda5
2122c19:dd:d9:dd:c25:c25:a003:eda6/1272c19:dd:d9:dd:c25:c25:a003:eda7
2132c19:dd:d9:dd:c25:c25:a003:eda8/1272c19:dd:d9:dd:c25:c25:a003:eda9
2142c19:dd:d9:dd:c25:c25:a003:edaa/1272c19:dd:d9:dd:c25:c25:a003:edab
2152c19:dd:d9:dd:c25:c25:a003:edac/1272c19:dd:d9:dd:c25:c25:a003:edad
2162c19:dd:d9:dd:c25:c25:a003:edae/1272c19:dd:d9:dd:c25:c25:a003:edaf
2172c19:dd:d9:dd:c25:c25:a003:edb0/1272c19:dd:d9:dd:c25:c25:a003:edb1
2182c19:dd:d9:dd:c25:c25:a003:edb2/1272c19:dd:d9:dd:c25:c25:a003:edb3
2192c19:dd:d9:dd:c25:c25:a003:edb4/1272c19:dd:d9:dd:c25:c25:a003:edb5
2202c19:dd:d9:dd:c25:c25:a003:edb6/1272c19:dd:d9:dd:c25:c25:a003:edb7
2212c19:dd:d9:dd:c25:c25:a003:edb8/1272c19:dd:d9:dd:c25:c25:a003:edb9
2222c19:dd:d9:dd:c25:c25:a003:edba/1272c19:dd:d9:dd:c25:c25:a003:edbb
2232c19:dd:d9:dd:c25:c25:a003:edbc/1272c19:dd:d9:dd:c25:c25:a003:edbd
2242c19:dd:d9:dd:c25:c25:a003:edbe/1272c19:dd:d9:dd:c25:c25:a003:edbf
2252c19:dd:d9:dd:c25:c25:a003:edc0/1272c19:dd:d9:dd:c25:c25:a003:edc1
2262c19:dd:d9:dd:c25:c25:a003:edc2/1272c19:dd:d9:dd:c25:c25:a003:edc3
2272c19:dd:d9:dd:c25:c25:a003:edc4/1272c19:dd:d9:dd:c25:c25:a003:edc5
2282c19:dd:d9:dd:c25:c25:a003:edc6/1272c19:dd:d9:dd:c25:c25:a003:edc7
2292c19:dd:d9:dd:c25:c25:a003:edc8/1272c19:dd:d9:dd:c25:c25:a003:edc9
2302c19:dd:d9:dd:c25:c25:a003:edca/1272c19:dd:d9:dd:c25:c25:a003:edcb
2312c19:dd:d9:dd:c25:c25:a003:edcc/1272c19:dd:d9:dd:c25:c25:a003:edcd
2322c19:dd:d9:dd:c25:c25:a003:edce/1272c19:dd:d9:dd:c25:c25:a003:edcf
2332c19:dd:d9:dd:c25:c25:a003:edd0/1272c19:dd:d9:dd:c25:c25:a003:edd1
2342c19:dd:d9:dd:c25:c25:a003:edd2/1272c19:dd:d9:dd:c25:c25:a003:edd3
2352c19:dd:d9:dd:c25:c25:a003:edd4/1272c19:dd:d9:dd:c25:c25:a003:edd5
2362c19:dd:d9:dd:c25:c25:a003:edd6/1272c19:dd:d9:dd:c25:c25:a003:edd7
2372c19:dd:d9:dd:c25:c25:a003:edd8/1272c19:dd:d9:dd:c25:c25:a003:edd9
2382c19:dd:d9:dd:c25:c25:a003:edda/1272c19:dd:d9:dd:c25:c25:a003:eddb
2392c19:dd:d9:dd:c25:c25:a003:eddc/1272c19:dd:d9:dd:c25:c25:a003:eddd
2402c19:dd:d9:dd:c25:c25:a003:edde/1272c19:dd:d9:dd:c25:c25:a003:eddf
2412c19:dd:d9:dd:c25:c25:a003:ede0/1272c19:dd:d9:dd:c25:c25:a003:ede1
2422c19:dd:d9:dd:c25:c25:a003:ede2/1272c19:dd:d9:dd:c25:c25:a003:ede3
2432c19:dd:d9:dd:c25:c25:a003:ede4/1272c19:dd:d9:dd:c25:c25:a003:ede5
2442c19:dd:d9:dd:c25:c25:a003:ede6/1272c19:dd:d9:dd:c25:c25:a003:ede7
2452c19:dd:d9:dd:c25:c25:a003:ede8/1272c19:dd:d9:dd:c25:c25:a003:ede9
2462c19:dd:d9:dd:c25:c25:a003:edea/1272c19:dd:d9:dd:c25:c25:a003:edeb
2472c19:dd:d9:dd:c25:c25:a003:edec/1272c19:dd:d9:dd:c25:c25:a003:eded
2482c19:dd:d9:dd:c25:c25:a003:edee/1272c19:dd:d9:dd:c25:c25:a003:edef
2492c19:dd:d9:dd:c25:c25:a003:edf0/1272c19:dd:d9:dd:c25:c25:a003:edf1
2502c19:dd:d9:dd:c25:c25:a003:edf2/1272c19:dd:d9:dd:c25:c25:a003:edf3
2512c19:dd:d9:dd:c25:c25:a003:edf4/1272c19:dd:d9:dd:c25:c25:a003:edf5
2522c19:dd:d9:dd:c25:c25:a003:edf6/1272c19:dd:d9:dd:c25:c25:a003:edf7
2532c19:dd:d9:dd:c25:c25:a003:edf8/1272c19:dd:d9:dd:c25:c25:a003:edf9
2542c19:dd:d9:dd:c25:c25:a003:edfa/1272c19:dd:d9:dd:c25:c25:a003:edfb
2552c19:dd:d9:dd:c25:c25:a003:edfc/1272c19:dd:d9:dd:c25:c25:a003:edfd
2562c19:dd:d9:dd:c25:c25:a003:edfe/1272c19:dd:d9:dd:c25:c25:a003:edff

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.