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:c25:c25d:dd:dd:dd:2e00/119
First address
2c19:dd:c25:c25d:dd:dd:dd:2e00
Last address
2c19:dd:c25:c25d:dd:dd:dd:2fff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:0c25:c25d:00dd:00dd:00dd:2e00
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
e.2.d.d.0.0.d.d.0.0.d.d.0.0.d.5.2.c.5.2.c.0.d.d.0.0.9.1.c.2.ip6.arpa
f.2.d.d.0.0.d.d.0.0.d.d.0.0.d.5.2.c.5.2.c.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:c25:c25d:dd:dd:dd:2e00/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:c25:c25d:dd:dd:dd:2e00/1272c19:dd:c25:c25d:dd:dd:dd:2e01
22c19:dd:c25:c25d:dd:dd:dd:2e02/1272c19:dd:c25:c25d:dd:dd:dd:2e03
32c19:dd:c25:c25d:dd:dd:dd:2e04/1272c19:dd:c25:c25d:dd:dd:dd:2e05
42c19:dd:c25:c25d:dd:dd:dd:2e06/1272c19:dd:c25:c25d:dd:dd:dd:2e07
52c19:dd:c25:c25d:dd:dd:dd:2e08/1272c19:dd:c25:c25d:dd:dd:dd:2e09
62c19:dd:c25:c25d:dd:dd:dd:2e0a/1272c19:dd:c25:c25d:dd:dd:dd:2e0b
72c19:dd:c25:c25d:dd:dd:dd:2e0c/1272c19:dd:c25:c25d:dd:dd:dd:2e0d
82c19:dd:c25:c25d:dd:dd:dd:2e0e/1272c19:dd:c25:c25d:dd:dd:dd:2e0f
92c19:dd:c25:c25d:dd:dd:dd:2e10/1272c19:dd:c25:c25d:dd:dd:dd:2e11
102c19:dd:c25:c25d:dd:dd:dd:2e12/1272c19:dd:c25:c25d:dd:dd:dd:2e13
112c19:dd:c25:c25d:dd:dd:dd:2e14/1272c19:dd:c25:c25d:dd:dd:dd:2e15
122c19:dd:c25:c25d:dd:dd:dd:2e16/1272c19:dd:c25:c25d:dd:dd:dd:2e17
132c19:dd:c25:c25d:dd:dd:dd:2e18/1272c19:dd:c25:c25d:dd:dd:dd:2e19
142c19:dd:c25:c25d:dd:dd:dd:2e1a/1272c19:dd:c25:c25d:dd:dd:dd:2e1b
152c19:dd:c25:c25d:dd:dd:dd:2e1c/1272c19:dd:c25:c25d:dd:dd:dd:2e1d
162c19:dd:c25:c25d:dd:dd:dd:2e1e/1272c19:dd:c25:c25d:dd:dd:dd:2e1f
172c19:dd:c25:c25d:dd:dd:dd:2e20/1272c19:dd:c25:c25d:dd:dd:dd:2e21
182c19:dd:c25:c25d:dd:dd:dd:2e22/1272c19:dd:c25:c25d:dd:dd:dd:2e23
192c19:dd:c25:c25d:dd:dd:dd:2e24/1272c19:dd:c25:c25d:dd:dd:dd:2e25
202c19:dd:c25:c25d:dd:dd:dd:2e26/1272c19:dd:c25:c25d:dd:dd:dd:2e27
212c19:dd:c25:c25d:dd:dd:dd:2e28/1272c19:dd:c25:c25d:dd:dd:dd:2e29
222c19:dd:c25:c25d:dd:dd:dd:2e2a/1272c19:dd:c25:c25d:dd:dd:dd:2e2b
232c19:dd:c25:c25d:dd:dd:dd:2e2c/1272c19:dd:c25:c25d:dd:dd:dd:2e2d
242c19:dd:c25:c25d:dd:dd:dd:2e2e/1272c19:dd:c25:c25d:dd:dd:dd:2e2f
252c19:dd:c25:c25d:dd:dd:dd:2e30/1272c19:dd:c25:c25d:dd:dd:dd:2e31
262c19:dd:c25:c25d:dd:dd:dd:2e32/1272c19:dd:c25:c25d:dd:dd:dd:2e33
272c19:dd:c25:c25d:dd:dd:dd:2e34/1272c19:dd:c25:c25d:dd:dd:dd:2e35
282c19:dd:c25:c25d:dd:dd:dd:2e36/1272c19:dd:c25:c25d:dd:dd:dd:2e37
292c19:dd:c25:c25d:dd:dd:dd:2e38/1272c19:dd:c25:c25d:dd:dd:dd:2e39
302c19:dd:c25:c25d:dd:dd:dd:2e3a/1272c19:dd:c25:c25d:dd:dd:dd:2e3b
312c19:dd:c25:c25d:dd:dd:dd:2e3c/1272c19:dd:c25:c25d:dd:dd:dd:2e3d
322c19:dd:c25:c25d:dd:dd:dd:2e3e/1272c19:dd:c25:c25d:dd:dd:dd:2e3f
332c19:dd:c25:c25d:dd:dd:dd:2e40/1272c19:dd:c25:c25d:dd:dd:dd:2e41
342c19:dd:c25:c25d:dd:dd:dd:2e42/1272c19:dd:c25:c25d:dd:dd:dd:2e43
352c19:dd:c25:c25d:dd:dd:dd:2e44/1272c19:dd:c25:c25d:dd:dd:dd:2e45
362c19:dd:c25:c25d:dd:dd:dd:2e46/1272c19:dd:c25:c25d:dd:dd:dd:2e47
372c19:dd:c25:c25d:dd:dd:dd:2e48/1272c19:dd:c25:c25d:dd:dd:dd:2e49
382c19:dd:c25:c25d:dd:dd:dd:2e4a/1272c19:dd:c25:c25d:dd:dd:dd:2e4b
392c19:dd:c25:c25d:dd:dd:dd:2e4c/1272c19:dd:c25:c25d:dd:dd:dd:2e4d
402c19:dd:c25:c25d:dd:dd:dd:2e4e/1272c19:dd:c25:c25d:dd:dd:dd:2e4f
412c19:dd:c25:c25d:dd:dd:dd:2e50/1272c19:dd:c25:c25d:dd:dd:dd:2e51
422c19:dd:c25:c25d:dd:dd:dd:2e52/1272c19:dd:c25:c25d:dd:dd:dd:2e53
432c19:dd:c25:c25d:dd:dd:dd:2e54/1272c19:dd:c25:c25d:dd:dd:dd:2e55
442c19:dd:c25:c25d:dd:dd:dd:2e56/1272c19:dd:c25:c25d:dd:dd:dd:2e57
452c19:dd:c25:c25d:dd:dd:dd:2e58/1272c19:dd:c25:c25d:dd:dd:dd:2e59
462c19:dd:c25:c25d:dd:dd:dd:2e5a/1272c19:dd:c25:c25d:dd:dd:dd:2e5b
472c19:dd:c25:c25d:dd:dd:dd:2e5c/1272c19:dd:c25:c25d:dd:dd:dd:2e5d
482c19:dd:c25:c25d:dd:dd:dd:2e5e/1272c19:dd:c25:c25d:dd:dd:dd:2e5f
492c19:dd:c25:c25d:dd:dd:dd:2e60/1272c19:dd:c25:c25d:dd:dd:dd:2e61
502c19:dd:c25:c25d:dd:dd:dd:2e62/1272c19:dd:c25:c25d:dd:dd:dd:2e63
512c19:dd:c25:c25d:dd:dd:dd:2e64/1272c19:dd:c25:c25d:dd:dd:dd:2e65
522c19:dd:c25:c25d:dd:dd:dd:2e66/1272c19:dd:c25:c25d:dd:dd:dd:2e67
532c19:dd:c25:c25d:dd:dd:dd:2e68/1272c19:dd:c25:c25d:dd:dd:dd:2e69
542c19:dd:c25:c25d:dd:dd:dd:2e6a/1272c19:dd:c25:c25d:dd:dd:dd:2e6b
552c19:dd:c25:c25d:dd:dd:dd:2e6c/1272c19:dd:c25:c25d:dd:dd:dd:2e6d
562c19:dd:c25:c25d:dd:dd:dd:2e6e/1272c19:dd:c25:c25d:dd:dd:dd:2e6f
572c19:dd:c25:c25d:dd:dd:dd:2e70/1272c19:dd:c25:c25d:dd:dd:dd:2e71
582c19:dd:c25:c25d:dd:dd:dd:2e72/1272c19:dd:c25:c25d:dd:dd:dd:2e73
592c19:dd:c25:c25d:dd:dd:dd:2e74/1272c19:dd:c25:c25d:dd:dd:dd:2e75
602c19:dd:c25:c25d:dd:dd:dd:2e76/1272c19:dd:c25:c25d:dd:dd:dd:2e77
612c19:dd:c25:c25d:dd:dd:dd:2e78/1272c19:dd:c25:c25d:dd:dd:dd:2e79
622c19:dd:c25:c25d:dd:dd:dd:2e7a/1272c19:dd:c25:c25d:dd:dd:dd:2e7b
632c19:dd:c25:c25d:dd:dd:dd:2e7c/1272c19:dd:c25:c25d:dd:dd:dd:2e7d
642c19:dd:c25:c25d:dd:dd:dd:2e7e/1272c19:dd:c25:c25d:dd:dd:dd:2e7f
652c19:dd:c25:c25d:dd:dd:dd:2e80/1272c19:dd:c25:c25d:dd:dd:dd:2e81
662c19:dd:c25:c25d:dd:dd:dd:2e82/1272c19:dd:c25:c25d:dd:dd:dd:2e83
672c19:dd:c25:c25d:dd:dd:dd:2e84/1272c19:dd:c25:c25d:dd:dd:dd:2e85
682c19:dd:c25:c25d:dd:dd:dd:2e86/1272c19:dd:c25:c25d:dd:dd:dd:2e87
692c19:dd:c25:c25d:dd:dd:dd:2e88/1272c19:dd:c25:c25d:dd:dd:dd:2e89
702c19:dd:c25:c25d:dd:dd:dd:2e8a/1272c19:dd:c25:c25d:dd:dd:dd:2e8b
712c19:dd:c25:c25d:dd:dd:dd:2e8c/1272c19:dd:c25:c25d:dd:dd:dd:2e8d
722c19:dd:c25:c25d:dd:dd:dd:2e8e/1272c19:dd:c25:c25d:dd:dd:dd:2e8f
732c19:dd:c25:c25d:dd:dd:dd:2e90/1272c19:dd:c25:c25d:dd:dd:dd:2e91
742c19:dd:c25:c25d:dd:dd:dd:2e92/1272c19:dd:c25:c25d:dd:dd:dd:2e93
752c19:dd:c25:c25d:dd:dd:dd:2e94/1272c19:dd:c25:c25d:dd:dd:dd:2e95
762c19:dd:c25:c25d:dd:dd:dd:2e96/1272c19:dd:c25:c25d:dd:dd:dd:2e97
772c19:dd:c25:c25d:dd:dd:dd:2e98/1272c19:dd:c25:c25d:dd:dd:dd:2e99
782c19:dd:c25:c25d:dd:dd:dd:2e9a/1272c19:dd:c25:c25d:dd:dd:dd:2e9b
792c19:dd:c25:c25d:dd:dd:dd:2e9c/1272c19:dd:c25:c25d:dd:dd:dd:2e9d
802c19:dd:c25:c25d:dd:dd:dd:2e9e/1272c19:dd:c25:c25d:dd:dd:dd:2e9f
812c19:dd:c25:c25d:dd:dd:dd:2ea0/1272c19:dd:c25:c25d:dd:dd:dd:2ea1
822c19:dd:c25:c25d:dd:dd:dd:2ea2/1272c19:dd:c25:c25d:dd:dd:dd:2ea3
832c19:dd:c25:c25d:dd:dd:dd:2ea4/1272c19:dd:c25:c25d:dd:dd:dd:2ea5
842c19:dd:c25:c25d:dd:dd:dd:2ea6/1272c19:dd:c25:c25d:dd:dd:dd:2ea7
852c19:dd:c25:c25d:dd:dd:dd:2ea8/1272c19:dd:c25:c25d:dd:dd:dd:2ea9
862c19:dd:c25:c25d:dd:dd:dd:2eaa/1272c19:dd:c25:c25d:dd:dd:dd:2eab
872c19:dd:c25:c25d:dd:dd:dd:2eac/1272c19:dd:c25:c25d:dd:dd:dd:2ead
882c19:dd:c25:c25d:dd:dd:dd:2eae/1272c19:dd:c25:c25d:dd:dd:dd:2eaf
892c19:dd:c25:c25d:dd:dd:dd:2eb0/1272c19:dd:c25:c25d:dd:dd:dd:2eb1
902c19:dd:c25:c25d:dd:dd:dd:2eb2/1272c19:dd:c25:c25d:dd:dd:dd:2eb3
912c19:dd:c25:c25d:dd:dd:dd:2eb4/1272c19:dd:c25:c25d:dd:dd:dd:2eb5
922c19:dd:c25:c25d:dd:dd:dd:2eb6/1272c19:dd:c25:c25d:dd:dd:dd:2eb7
932c19:dd:c25:c25d:dd:dd:dd:2eb8/1272c19:dd:c25:c25d:dd:dd:dd:2eb9
942c19:dd:c25:c25d:dd:dd:dd:2eba/1272c19:dd:c25:c25d:dd:dd:dd:2ebb
952c19:dd:c25:c25d:dd:dd:dd:2ebc/1272c19:dd:c25:c25d:dd:dd:dd:2ebd
962c19:dd:c25:c25d:dd:dd:dd:2ebe/1272c19:dd:c25:c25d:dd:dd:dd:2ebf
972c19:dd:c25:c25d:dd:dd:dd:2ec0/1272c19:dd:c25:c25d:dd:dd:dd:2ec1
982c19:dd:c25:c25d:dd:dd:dd:2ec2/1272c19:dd:c25:c25d:dd:dd:dd:2ec3
992c19:dd:c25:c25d:dd:dd:dd:2ec4/1272c19:dd:c25:c25d:dd:dd:dd:2ec5
1002c19:dd:c25:c25d:dd:dd:dd:2ec6/1272c19:dd:c25:c25d:dd:dd:dd:2ec7
1012c19:dd:c25:c25d:dd:dd:dd:2ec8/1272c19:dd:c25:c25d:dd:dd:dd:2ec9
1022c19:dd:c25:c25d:dd:dd:dd:2eca/1272c19:dd:c25:c25d:dd:dd:dd:2ecb
1032c19:dd:c25:c25d:dd:dd:dd:2ecc/1272c19:dd:c25:c25d:dd:dd:dd:2ecd
1042c19:dd:c25:c25d:dd:dd:dd:2ece/1272c19:dd:c25:c25d:dd:dd:dd:2ecf
1052c19:dd:c25:c25d:dd:dd:dd:2ed0/1272c19:dd:c25:c25d:dd:dd:dd:2ed1
1062c19:dd:c25:c25d:dd:dd:dd:2ed2/1272c19:dd:c25:c25d:dd:dd:dd:2ed3
1072c19:dd:c25:c25d:dd:dd:dd:2ed4/1272c19:dd:c25:c25d:dd:dd:dd:2ed5
1082c19:dd:c25:c25d:dd:dd:dd:2ed6/1272c19:dd:c25:c25d:dd:dd:dd:2ed7
1092c19:dd:c25:c25d:dd:dd:dd:2ed8/1272c19:dd:c25:c25d:dd:dd:dd:2ed9
1102c19:dd:c25:c25d:dd:dd:dd:2eda/1272c19:dd:c25:c25d:dd:dd:dd:2edb
1112c19:dd:c25:c25d:dd:dd:dd:2edc/1272c19:dd:c25:c25d:dd:dd:dd:2edd
1122c19:dd:c25:c25d:dd:dd:dd:2ede/1272c19:dd:c25:c25d:dd:dd:dd:2edf
1132c19:dd:c25:c25d:dd:dd:dd:2ee0/1272c19:dd:c25:c25d:dd:dd:dd:2ee1
1142c19:dd:c25:c25d:dd:dd:dd:2ee2/1272c19:dd:c25:c25d:dd:dd:dd:2ee3
1152c19:dd:c25:c25d:dd:dd:dd:2ee4/1272c19:dd:c25:c25d:dd:dd:dd:2ee5
1162c19:dd:c25:c25d:dd:dd:dd:2ee6/1272c19:dd:c25:c25d:dd:dd:dd:2ee7
1172c19:dd:c25:c25d:dd:dd:dd:2ee8/1272c19:dd:c25:c25d:dd:dd:dd:2ee9
1182c19:dd:c25:c25d:dd:dd:dd:2eea/1272c19:dd:c25:c25d:dd:dd:dd:2eeb
1192c19:dd:c25:c25d:dd:dd:dd:2eec/1272c19:dd:c25:c25d:dd:dd:dd:2eed
1202c19:dd:c25:c25d:dd:dd:dd:2eee/1272c19:dd:c25:c25d:dd:dd:dd:2eef
1212c19:dd:c25:c25d:dd:dd:dd:2ef0/1272c19:dd:c25:c25d:dd:dd:dd:2ef1
1222c19:dd:c25:c25d:dd:dd:dd:2ef2/1272c19:dd:c25:c25d:dd:dd:dd:2ef3
1232c19:dd:c25:c25d:dd:dd:dd:2ef4/1272c19:dd:c25:c25d:dd:dd:dd:2ef5
1242c19:dd:c25:c25d:dd:dd:dd:2ef6/1272c19:dd:c25:c25d:dd:dd:dd:2ef7
1252c19:dd:c25:c25d:dd:dd:dd:2ef8/1272c19:dd:c25:c25d:dd:dd:dd:2ef9
1262c19:dd:c25:c25d:dd:dd:dd:2efa/1272c19:dd:c25:c25d:dd:dd:dd:2efb
1272c19:dd:c25:c25d:dd:dd:dd:2efc/1272c19:dd:c25:c25d:dd:dd:dd:2efd
1282c19:dd:c25:c25d:dd:dd:dd:2efe/1272c19:dd:c25:c25d:dd:dd:dd:2eff
1292c19:dd:c25:c25d:dd:dd:dd:2f00/1272c19:dd:c25:c25d:dd:dd:dd:2f01
1302c19:dd:c25:c25d:dd:dd:dd:2f02/1272c19:dd:c25:c25d:dd:dd:dd:2f03
1312c19:dd:c25:c25d:dd:dd:dd:2f04/1272c19:dd:c25:c25d:dd:dd:dd:2f05
1322c19:dd:c25:c25d:dd:dd:dd:2f06/1272c19:dd:c25:c25d:dd:dd:dd:2f07
1332c19:dd:c25:c25d:dd:dd:dd:2f08/1272c19:dd:c25:c25d:dd:dd:dd:2f09
1342c19:dd:c25:c25d:dd:dd:dd:2f0a/1272c19:dd:c25:c25d:dd:dd:dd:2f0b
1352c19:dd:c25:c25d:dd:dd:dd:2f0c/1272c19:dd:c25:c25d:dd:dd:dd:2f0d
1362c19:dd:c25:c25d:dd:dd:dd:2f0e/1272c19:dd:c25:c25d:dd:dd:dd:2f0f
1372c19:dd:c25:c25d:dd:dd:dd:2f10/1272c19:dd:c25:c25d:dd:dd:dd:2f11
1382c19:dd:c25:c25d:dd:dd:dd:2f12/1272c19:dd:c25:c25d:dd:dd:dd:2f13
1392c19:dd:c25:c25d:dd:dd:dd:2f14/1272c19:dd:c25:c25d:dd:dd:dd:2f15
1402c19:dd:c25:c25d:dd:dd:dd:2f16/1272c19:dd:c25:c25d:dd:dd:dd:2f17
1412c19:dd:c25:c25d:dd:dd:dd:2f18/1272c19:dd:c25:c25d:dd:dd:dd:2f19
1422c19:dd:c25:c25d:dd:dd:dd:2f1a/1272c19:dd:c25:c25d:dd:dd:dd:2f1b
1432c19:dd:c25:c25d:dd:dd:dd:2f1c/1272c19:dd:c25:c25d:dd:dd:dd:2f1d
1442c19:dd:c25:c25d:dd:dd:dd:2f1e/1272c19:dd:c25:c25d:dd:dd:dd:2f1f
1452c19:dd:c25:c25d:dd:dd:dd:2f20/1272c19:dd:c25:c25d:dd:dd:dd:2f21
1462c19:dd:c25:c25d:dd:dd:dd:2f22/1272c19:dd:c25:c25d:dd:dd:dd:2f23
1472c19:dd:c25:c25d:dd:dd:dd:2f24/1272c19:dd:c25:c25d:dd:dd:dd:2f25
1482c19:dd:c25:c25d:dd:dd:dd:2f26/1272c19:dd:c25:c25d:dd:dd:dd:2f27
1492c19:dd:c25:c25d:dd:dd:dd:2f28/1272c19:dd:c25:c25d:dd:dd:dd:2f29
1502c19:dd:c25:c25d:dd:dd:dd:2f2a/1272c19:dd:c25:c25d:dd:dd:dd:2f2b
1512c19:dd:c25:c25d:dd:dd:dd:2f2c/1272c19:dd:c25:c25d:dd:dd:dd:2f2d
1522c19:dd:c25:c25d:dd:dd:dd:2f2e/1272c19:dd:c25:c25d:dd:dd:dd:2f2f
1532c19:dd:c25:c25d:dd:dd:dd:2f30/1272c19:dd:c25:c25d:dd:dd:dd:2f31
1542c19:dd:c25:c25d:dd:dd:dd:2f32/1272c19:dd:c25:c25d:dd:dd:dd:2f33
1552c19:dd:c25:c25d:dd:dd:dd:2f34/1272c19:dd:c25:c25d:dd:dd:dd:2f35
1562c19:dd:c25:c25d:dd:dd:dd:2f36/1272c19:dd:c25:c25d:dd:dd:dd:2f37
1572c19:dd:c25:c25d:dd:dd:dd:2f38/1272c19:dd:c25:c25d:dd:dd:dd:2f39
1582c19:dd:c25:c25d:dd:dd:dd:2f3a/1272c19:dd:c25:c25d:dd:dd:dd:2f3b
1592c19:dd:c25:c25d:dd:dd:dd:2f3c/1272c19:dd:c25:c25d:dd:dd:dd:2f3d
1602c19:dd:c25:c25d:dd:dd:dd:2f3e/1272c19:dd:c25:c25d:dd:dd:dd:2f3f
1612c19:dd:c25:c25d:dd:dd:dd:2f40/1272c19:dd:c25:c25d:dd:dd:dd:2f41
1622c19:dd:c25:c25d:dd:dd:dd:2f42/1272c19:dd:c25:c25d:dd:dd:dd:2f43
1632c19:dd:c25:c25d:dd:dd:dd:2f44/1272c19:dd:c25:c25d:dd:dd:dd:2f45
1642c19:dd:c25:c25d:dd:dd:dd:2f46/1272c19:dd:c25:c25d:dd:dd:dd:2f47
1652c19:dd:c25:c25d:dd:dd:dd:2f48/1272c19:dd:c25:c25d:dd:dd:dd:2f49
1662c19:dd:c25:c25d:dd:dd:dd:2f4a/1272c19:dd:c25:c25d:dd:dd:dd:2f4b
1672c19:dd:c25:c25d:dd:dd:dd:2f4c/1272c19:dd:c25:c25d:dd:dd:dd:2f4d
1682c19:dd:c25:c25d:dd:dd:dd:2f4e/1272c19:dd:c25:c25d:dd:dd:dd:2f4f
1692c19:dd:c25:c25d:dd:dd:dd:2f50/1272c19:dd:c25:c25d:dd:dd:dd:2f51
1702c19:dd:c25:c25d:dd:dd:dd:2f52/1272c19:dd:c25:c25d:dd:dd:dd:2f53
1712c19:dd:c25:c25d:dd:dd:dd:2f54/1272c19:dd:c25:c25d:dd:dd:dd:2f55
1722c19:dd:c25:c25d:dd:dd:dd:2f56/1272c19:dd:c25:c25d:dd:dd:dd:2f57
1732c19:dd:c25:c25d:dd:dd:dd:2f58/1272c19:dd:c25:c25d:dd:dd:dd:2f59
1742c19:dd:c25:c25d:dd:dd:dd:2f5a/1272c19:dd:c25:c25d:dd:dd:dd:2f5b
1752c19:dd:c25:c25d:dd:dd:dd:2f5c/1272c19:dd:c25:c25d:dd:dd:dd:2f5d
1762c19:dd:c25:c25d:dd:dd:dd:2f5e/1272c19:dd:c25:c25d:dd:dd:dd:2f5f
1772c19:dd:c25:c25d:dd:dd:dd:2f60/1272c19:dd:c25:c25d:dd:dd:dd:2f61
1782c19:dd:c25:c25d:dd:dd:dd:2f62/1272c19:dd:c25:c25d:dd:dd:dd:2f63
1792c19:dd:c25:c25d:dd:dd:dd:2f64/1272c19:dd:c25:c25d:dd:dd:dd:2f65
1802c19:dd:c25:c25d:dd:dd:dd:2f66/1272c19:dd:c25:c25d:dd:dd:dd:2f67
1812c19:dd:c25:c25d:dd:dd:dd:2f68/1272c19:dd:c25:c25d:dd:dd:dd:2f69
1822c19:dd:c25:c25d:dd:dd:dd:2f6a/1272c19:dd:c25:c25d:dd:dd:dd:2f6b
1832c19:dd:c25:c25d:dd:dd:dd:2f6c/1272c19:dd:c25:c25d:dd:dd:dd:2f6d
1842c19:dd:c25:c25d:dd:dd:dd:2f6e/1272c19:dd:c25:c25d:dd:dd:dd:2f6f
1852c19:dd:c25:c25d:dd:dd:dd:2f70/1272c19:dd:c25:c25d:dd:dd:dd:2f71
1862c19:dd:c25:c25d:dd:dd:dd:2f72/1272c19:dd:c25:c25d:dd:dd:dd:2f73
1872c19:dd:c25:c25d:dd:dd:dd:2f74/1272c19:dd:c25:c25d:dd:dd:dd:2f75
1882c19:dd:c25:c25d:dd:dd:dd:2f76/1272c19:dd:c25:c25d:dd:dd:dd:2f77
1892c19:dd:c25:c25d:dd:dd:dd:2f78/1272c19:dd:c25:c25d:dd:dd:dd:2f79
1902c19:dd:c25:c25d:dd:dd:dd:2f7a/1272c19:dd:c25:c25d:dd:dd:dd:2f7b
1912c19:dd:c25:c25d:dd:dd:dd:2f7c/1272c19:dd:c25:c25d:dd:dd:dd:2f7d
1922c19:dd:c25:c25d:dd:dd:dd:2f7e/1272c19:dd:c25:c25d:dd:dd:dd:2f7f
1932c19:dd:c25:c25d:dd:dd:dd:2f80/1272c19:dd:c25:c25d:dd:dd:dd:2f81
1942c19:dd:c25:c25d:dd:dd:dd:2f82/1272c19:dd:c25:c25d:dd:dd:dd:2f83
1952c19:dd:c25:c25d:dd:dd:dd:2f84/1272c19:dd:c25:c25d:dd:dd:dd:2f85
1962c19:dd:c25:c25d:dd:dd:dd:2f86/1272c19:dd:c25:c25d:dd:dd:dd:2f87
1972c19:dd:c25:c25d:dd:dd:dd:2f88/1272c19:dd:c25:c25d:dd:dd:dd:2f89
1982c19:dd:c25:c25d:dd:dd:dd:2f8a/1272c19:dd:c25:c25d:dd:dd:dd:2f8b
1992c19:dd:c25:c25d:dd:dd:dd:2f8c/1272c19:dd:c25:c25d:dd:dd:dd:2f8d
2002c19:dd:c25:c25d:dd:dd:dd:2f8e/1272c19:dd:c25:c25d:dd:dd:dd:2f8f
2012c19:dd:c25:c25d:dd:dd:dd:2f90/1272c19:dd:c25:c25d:dd:dd:dd:2f91
2022c19:dd:c25:c25d:dd:dd:dd:2f92/1272c19:dd:c25:c25d:dd:dd:dd:2f93
2032c19:dd:c25:c25d:dd:dd:dd:2f94/1272c19:dd:c25:c25d:dd:dd:dd:2f95
2042c19:dd:c25:c25d:dd:dd:dd:2f96/1272c19:dd:c25:c25d:dd:dd:dd:2f97
2052c19:dd:c25:c25d:dd:dd:dd:2f98/1272c19:dd:c25:c25d:dd:dd:dd:2f99
2062c19:dd:c25:c25d:dd:dd:dd:2f9a/1272c19:dd:c25:c25d:dd:dd:dd:2f9b
2072c19:dd:c25:c25d:dd:dd:dd:2f9c/1272c19:dd:c25:c25d:dd:dd:dd:2f9d
2082c19:dd:c25:c25d:dd:dd:dd:2f9e/1272c19:dd:c25:c25d:dd:dd:dd:2f9f
2092c19:dd:c25:c25d:dd:dd:dd:2fa0/1272c19:dd:c25:c25d:dd:dd:dd:2fa1
2102c19:dd:c25:c25d:dd:dd:dd:2fa2/1272c19:dd:c25:c25d:dd:dd:dd:2fa3
2112c19:dd:c25:c25d:dd:dd:dd:2fa4/1272c19:dd:c25:c25d:dd:dd:dd:2fa5
2122c19:dd:c25:c25d:dd:dd:dd:2fa6/1272c19:dd:c25:c25d:dd:dd:dd:2fa7
2132c19:dd:c25:c25d:dd:dd:dd:2fa8/1272c19:dd:c25:c25d:dd:dd:dd:2fa9
2142c19:dd:c25:c25d:dd:dd:dd:2faa/1272c19:dd:c25:c25d:dd:dd:dd:2fab
2152c19:dd:c25:c25d:dd:dd:dd:2fac/1272c19:dd:c25:c25d:dd:dd:dd:2fad
2162c19:dd:c25:c25d:dd:dd:dd:2fae/1272c19:dd:c25:c25d:dd:dd:dd:2faf
2172c19:dd:c25:c25d:dd:dd:dd:2fb0/1272c19:dd:c25:c25d:dd:dd:dd:2fb1
2182c19:dd:c25:c25d:dd:dd:dd:2fb2/1272c19:dd:c25:c25d:dd:dd:dd:2fb3
2192c19:dd:c25:c25d:dd:dd:dd:2fb4/1272c19:dd:c25:c25d:dd:dd:dd:2fb5
2202c19:dd:c25:c25d:dd:dd:dd:2fb6/1272c19:dd:c25:c25d:dd:dd:dd:2fb7
2212c19:dd:c25:c25d:dd:dd:dd:2fb8/1272c19:dd:c25:c25d:dd:dd:dd:2fb9
2222c19:dd:c25:c25d:dd:dd:dd:2fba/1272c19:dd:c25:c25d:dd:dd:dd:2fbb
2232c19:dd:c25:c25d:dd:dd:dd:2fbc/1272c19:dd:c25:c25d:dd:dd:dd:2fbd
2242c19:dd:c25:c25d:dd:dd:dd:2fbe/1272c19:dd:c25:c25d:dd:dd:dd:2fbf
2252c19:dd:c25:c25d:dd:dd:dd:2fc0/1272c19:dd:c25:c25d:dd:dd:dd:2fc1
2262c19:dd:c25:c25d:dd:dd:dd:2fc2/1272c19:dd:c25:c25d:dd:dd:dd:2fc3
2272c19:dd:c25:c25d:dd:dd:dd:2fc4/1272c19:dd:c25:c25d:dd:dd:dd:2fc5
2282c19:dd:c25:c25d:dd:dd:dd:2fc6/1272c19:dd:c25:c25d:dd:dd:dd:2fc7
2292c19:dd:c25:c25d:dd:dd:dd:2fc8/1272c19:dd:c25:c25d:dd:dd:dd:2fc9
2302c19:dd:c25:c25d:dd:dd:dd:2fca/1272c19:dd:c25:c25d:dd:dd:dd:2fcb
2312c19:dd:c25:c25d:dd:dd:dd:2fcc/1272c19:dd:c25:c25d:dd:dd:dd:2fcd
2322c19:dd:c25:c25d:dd:dd:dd:2fce/1272c19:dd:c25:c25d:dd:dd:dd:2fcf
2332c19:dd:c25:c25d:dd:dd:dd:2fd0/1272c19:dd:c25:c25d:dd:dd:dd:2fd1
2342c19:dd:c25:c25d:dd:dd:dd:2fd2/1272c19:dd:c25:c25d:dd:dd:dd:2fd3
2352c19:dd:c25:c25d:dd:dd:dd:2fd4/1272c19:dd:c25:c25d:dd:dd:dd:2fd5
2362c19:dd:c25:c25d:dd:dd:dd:2fd6/1272c19:dd:c25:c25d:dd:dd:dd:2fd7
2372c19:dd:c25:c25d:dd:dd:dd:2fd8/1272c19:dd:c25:c25d:dd:dd:dd:2fd9
2382c19:dd:c25:c25d:dd:dd:dd:2fda/1272c19:dd:c25:c25d:dd:dd:dd:2fdb
2392c19:dd:c25:c25d:dd:dd:dd:2fdc/1272c19:dd:c25:c25d:dd:dd:dd:2fdd
2402c19:dd:c25:c25d:dd:dd:dd:2fde/1272c19:dd:c25:c25d:dd:dd:dd:2fdf
2412c19:dd:c25:c25d:dd:dd:dd:2fe0/1272c19:dd:c25:c25d:dd:dd:dd:2fe1
2422c19:dd:c25:c25d:dd:dd:dd:2fe2/1272c19:dd:c25:c25d:dd:dd:dd:2fe3
2432c19:dd:c25:c25d:dd:dd:dd:2fe4/1272c19:dd:c25:c25d:dd:dd:dd:2fe5
2442c19:dd:c25:c25d:dd:dd:dd:2fe6/1272c19:dd:c25:c25d:dd:dd:dd:2fe7
2452c19:dd:c25:c25d:dd:dd:dd:2fe8/1272c19:dd:c25:c25d:dd:dd:dd:2fe9
2462c19:dd:c25:c25d:dd:dd:dd:2fea/1272c19:dd:c25:c25d:dd:dd:dd:2feb
2472c19:dd:c25:c25d:dd:dd:dd:2fec/1272c19:dd:c25:c25d:dd:dd:dd:2fed
2482c19:dd:c25:c25d:dd:dd:dd:2fee/1272c19:dd:c25:c25d:dd:dd:dd:2fef
2492c19:dd:c25:c25d:dd:dd:dd:2ff0/1272c19:dd:c25:c25d:dd:dd:dd:2ff1
2502c19:dd:c25:c25d:dd:dd:dd:2ff2/1272c19:dd:c25:c25d:dd:dd:dd:2ff3
2512c19:dd:c25:c25d:dd:dd:dd:2ff4/1272c19:dd:c25:c25d:dd:dd:dd:2ff5
2522c19:dd:c25:c25d:dd:dd:dd:2ff6/1272c19:dd:c25:c25d:dd:dd:dd:2ff7
2532c19:dd:c25:c25d:dd:dd:dd:2ff8/1272c19:dd:c25:c25d:dd:dd:dd:2ff9
2542c19:dd:c25:c25d:dd:dd:dd:2ffa/1272c19:dd:c25:c25d:dd:dd:dd:2ffb
2552c19:dd:c25:c25d:dd:dd:dd:2ffc/1272c19:dd:c25:c25d:dd:dd:dd:2ffd
2562c19:dd:c25:c25d:dd:dd:dd:2ffe/1272c19:dd:c25:c25d:dd:dd:dd:2fff

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.