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/116
Addresses4,096
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:f00a:c000/116
First address
2c19:dd:d9:dd:c25:c25:f00a:c000
Last address
2c19:dd:d9:dd:c25:c25:f00a:cfff
Addresses
4,096
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:f00a:c000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
c.a.0.0.f.5.2.c.0.5.2.c.0.d.d.0.0.9.d.0.0.d.d.0.0.9.1.c.2.ip6.arpa
Split into smaller subnets/128
/117 (2)/118 (4)/119 (8)/120 (16)/124 (256)/127 (2,048)/128 (4,096)

2c19:dd:d9:dd:c25:c25:f00a:c000/116 makes 4,096 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:f00a:c000/1282c19:dd:d9:dd:c25:c25:f00a:c000
22c19:dd:d9:dd:c25:c25:f00a:c001/1282c19:dd:d9:dd:c25:c25:f00a:c001
32c19:dd:d9:dd:c25:c25:f00a:c002/1282c19:dd:d9:dd:c25:c25:f00a:c002
42c19:dd:d9:dd:c25:c25:f00a:c003/1282c19:dd:d9:dd:c25:c25:f00a:c003
52c19:dd:d9:dd:c25:c25:f00a:c004/1282c19:dd:d9:dd:c25:c25:f00a:c004
62c19:dd:d9:dd:c25:c25:f00a:c005/1282c19:dd:d9:dd:c25:c25:f00a:c005
72c19:dd:d9:dd:c25:c25:f00a:c006/1282c19:dd:d9:dd:c25:c25:f00a:c006
82c19:dd:d9:dd:c25:c25:f00a:c007/1282c19:dd:d9:dd:c25:c25:f00a:c007
92c19:dd:d9:dd:c25:c25:f00a:c008/1282c19:dd:d9:dd:c25:c25:f00a:c008
102c19:dd:d9:dd:c25:c25:f00a:c009/1282c19:dd:d9:dd:c25:c25:f00a:c009
112c19:dd:d9:dd:c25:c25:f00a:c00a/1282c19:dd:d9:dd:c25:c25:f00a:c00a
122c19:dd:d9:dd:c25:c25:f00a:c00b/1282c19:dd:d9:dd:c25:c25:f00a:c00b
132c19:dd:d9:dd:c25:c25:f00a:c00c/1282c19:dd:d9:dd:c25:c25:f00a:c00c
142c19:dd:d9:dd:c25:c25:f00a:c00d/1282c19:dd:d9:dd:c25:c25:f00a:c00d
152c19:dd:d9:dd:c25:c25:f00a:c00e/1282c19:dd:d9:dd:c25:c25:f00a:c00e
162c19:dd:d9:dd:c25:c25:f00a:c00f/1282c19:dd:d9:dd:c25:c25:f00a:c00f
172c19:dd:d9:dd:c25:c25:f00a:c010/1282c19:dd:d9:dd:c25:c25:f00a:c010
182c19:dd:d9:dd:c25:c25:f00a:c011/1282c19:dd:d9:dd:c25:c25:f00a:c011
192c19:dd:d9:dd:c25:c25:f00a:c012/1282c19:dd:d9:dd:c25:c25:f00a:c012
202c19:dd:d9:dd:c25:c25:f00a:c013/1282c19:dd:d9:dd:c25:c25:f00a:c013
212c19:dd:d9:dd:c25:c25:f00a:c014/1282c19:dd:d9:dd:c25:c25:f00a:c014
222c19:dd:d9:dd:c25:c25:f00a:c015/1282c19:dd:d9:dd:c25:c25:f00a:c015
232c19:dd:d9:dd:c25:c25:f00a:c016/1282c19:dd:d9:dd:c25:c25:f00a:c016
242c19:dd:d9:dd:c25:c25:f00a:c017/1282c19:dd:d9:dd:c25:c25:f00a:c017
252c19:dd:d9:dd:c25:c25:f00a:c018/1282c19:dd:d9:dd:c25:c25:f00a:c018
262c19:dd:d9:dd:c25:c25:f00a:c019/1282c19:dd:d9:dd:c25:c25:f00a:c019
272c19:dd:d9:dd:c25:c25:f00a:c01a/1282c19:dd:d9:dd:c25:c25:f00a:c01a
282c19:dd:d9:dd:c25:c25:f00a:c01b/1282c19:dd:d9:dd:c25:c25:f00a:c01b
292c19:dd:d9:dd:c25:c25:f00a:c01c/1282c19:dd:d9:dd:c25:c25:f00a:c01c
302c19:dd:d9:dd:c25:c25:f00a:c01d/1282c19:dd:d9:dd:c25:c25:f00a:c01d
312c19:dd:d9:dd:c25:c25:f00a:c01e/1282c19:dd:d9:dd:c25:c25:f00a:c01e
322c19:dd:d9:dd:c25:c25:f00a:c01f/1282c19:dd:d9:dd:c25:c25:f00a:c01f
332c19:dd:d9:dd:c25:c25:f00a:c020/1282c19:dd:d9:dd:c25:c25:f00a:c020
342c19:dd:d9:dd:c25:c25:f00a:c021/1282c19:dd:d9:dd:c25:c25:f00a:c021
352c19:dd:d9:dd:c25:c25:f00a:c022/1282c19:dd:d9:dd:c25:c25:f00a:c022
362c19:dd:d9:dd:c25:c25:f00a:c023/1282c19:dd:d9:dd:c25:c25:f00a:c023
372c19:dd:d9:dd:c25:c25:f00a:c024/1282c19:dd:d9:dd:c25:c25:f00a:c024
382c19:dd:d9:dd:c25:c25:f00a:c025/1282c19:dd:d9:dd:c25:c25:f00a:c025
392c19:dd:d9:dd:c25:c25:f00a:c026/1282c19:dd:d9:dd:c25:c25:f00a:c026
402c19:dd:d9:dd:c25:c25:f00a:c027/1282c19:dd:d9:dd:c25:c25:f00a:c027
412c19:dd:d9:dd:c25:c25:f00a:c028/1282c19:dd:d9:dd:c25:c25:f00a:c028
422c19:dd:d9:dd:c25:c25:f00a:c029/1282c19:dd:d9:dd:c25:c25:f00a:c029
432c19:dd:d9:dd:c25:c25:f00a:c02a/1282c19:dd:d9:dd:c25:c25:f00a:c02a
442c19:dd:d9:dd:c25:c25:f00a:c02b/1282c19:dd:d9:dd:c25:c25:f00a:c02b
452c19:dd:d9:dd:c25:c25:f00a:c02c/1282c19:dd:d9:dd:c25:c25:f00a:c02c
462c19:dd:d9:dd:c25:c25:f00a:c02d/1282c19:dd:d9:dd:c25:c25:f00a:c02d
472c19:dd:d9:dd:c25:c25:f00a:c02e/1282c19:dd:d9:dd:c25:c25:f00a:c02e
482c19:dd:d9:dd:c25:c25:f00a:c02f/1282c19:dd:d9:dd:c25:c25:f00a:c02f
492c19:dd:d9:dd:c25:c25:f00a:c030/1282c19:dd:d9:dd:c25:c25:f00a:c030
502c19:dd:d9:dd:c25:c25:f00a:c031/1282c19:dd:d9:dd:c25:c25:f00a:c031
512c19:dd:d9:dd:c25:c25:f00a:c032/1282c19:dd:d9:dd:c25:c25:f00a:c032
522c19:dd:d9:dd:c25:c25:f00a:c033/1282c19:dd:d9:dd:c25:c25:f00a:c033
532c19:dd:d9:dd:c25:c25:f00a:c034/1282c19:dd:d9:dd:c25:c25:f00a:c034
542c19:dd:d9:dd:c25:c25:f00a:c035/1282c19:dd:d9:dd:c25:c25:f00a:c035
552c19:dd:d9:dd:c25:c25:f00a:c036/1282c19:dd:d9:dd:c25:c25:f00a:c036
562c19:dd:d9:dd:c25:c25:f00a:c037/1282c19:dd:d9:dd:c25:c25:f00a:c037
572c19:dd:d9:dd:c25:c25:f00a:c038/1282c19:dd:d9:dd:c25:c25:f00a:c038
582c19:dd:d9:dd:c25:c25:f00a:c039/1282c19:dd:d9:dd:c25:c25:f00a:c039
592c19:dd:d9:dd:c25:c25:f00a:c03a/1282c19:dd:d9:dd:c25:c25:f00a:c03a
602c19:dd:d9:dd:c25:c25:f00a:c03b/1282c19:dd:d9:dd:c25:c25:f00a:c03b
612c19:dd:d9:dd:c25:c25:f00a:c03c/1282c19:dd:d9:dd:c25:c25:f00a:c03c
622c19:dd:d9:dd:c25:c25:f00a:c03d/1282c19:dd:d9:dd:c25:c25:f00a:c03d
632c19:dd:d9:dd:c25:c25:f00a:c03e/1282c19:dd:d9:dd:c25:c25:f00a:c03e
642c19:dd:d9:dd:c25:c25:f00a:c03f/1282c19:dd:d9:dd:c25:c25:f00a:c03f
652c19:dd:d9:dd:c25:c25:f00a:c040/1282c19:dd:d9:dd:c25:c25:f00a:c040
662c19:dd:d9:dd:c25:c25:f00a:c041/1282c19:dd:d9:dd:c25:c25:f00a:c041
672c19:dd:d9:dd:c25:c25:f00a:c042/1282c19:dd:d9:dd:c25:c25:f00a:c042
682c19:dd:d9:dd:c25:c25:f00a:c043/1282c19:dd:d9:dd:c25:c25:f00a:c043
692c19:dd:d9:dd:c25:c25:f00a:c044/1282c19:dd:d9:dd:c25:c25:f00a:c044
702c19:dd:d9:dd:c25:c25:f00a:c045/1282c19:dd:d9:dd:c25:c25:f00a:c045
712c19:dd:d9:dd:c25:c25:f00a:c046/1282c19:dd:d9:dd:c25:c25:f00a:c046
722c19:dd:d9:dd:c25:c25:f00a:c047/1282c19:dd:d9:dd:c25:c25:f00a:c047
732c19:dd:d9:dd:c25:c25:f00a:c048/1282c19:dd:d9:dd:c25:c25:f00a:c048
742c19:dd:d9:dd:c25:c25:f00a:c049/1282c19:dd:d9:dd:c25:c25:f00a:c049
752c19:dd:d9:dd:c25:c25:f00a:c04a/1282c19:dd:d9:dd:c25:c25:f00a:c04a
762c19:dd:d9:dd:c25:c25:f00a:c04b/1282c19:dd:d9:dd:c25:c25:f00a:c04b
772c19:dd:d9:dd:c25:c25:f00a:c04c/1282c19:dd:d9:dd:c25:c25:f00a:c04c
782c19:dd:d9:dd:c25:c25:f00a:c04d/1282c19:dd:d9:dd:c25:c25:f00a:c04d
792c19:dd:d9:dd:c25:c25:f00a:c04e/1282c19:dd:d9:dd:c25:c25:f00a:c04e
802c19:dd:d9:dd:c25:c25:f00a:c04f/1282c19:dd:d9:dd:c25:c25:f00a:c04f
812c19:dd:d9:dd:c25:c25:f00a:c050/1282c19:dd:d9:dd:c25:c25:f00a:c050
822c19:dd:d9:dd:c25:c25:f00a:c051/1282c19:dd:d9:dd:c25:c25:f00a:c051
832c19:dd:d9:dd:c25:c25:f00a:c052/1282c19:dd:d9:dd:c25:c25:f00a:c052
842c19:dd:d9:dd:c25:c25:f00a:c053/1282c19:dd:d9:dd:c25:c25:f00a:c053
852c19:dd:d9:dd:c25:c25:f00a:c054/1282c19:dd:d9:dd:c25:c25:f00a:c054
862c19:dd:d9:dd:c25:c25:f00a:c055/1282c19:dd:d9:dd:c25:c25:f00a:c055
872c19:dd:d9:dd:c25:c25:f00a:c056/1282c19:dd:d9:dd:c25:c25:f00a:c056
882c19:dd:d9:dd:c25:c25:f00a:c057/1282c19:dd:d9:dd:c25:c25:f00a:c057
892c19:dd:d9:dd:c25:c25:f00a:c058/1282c19:dd:d9:dd:c25:c25:f00a:c058
902c19:dd:d9:dd:c25:c25:f00a:c059/1282c19:dd:d9:dd:c25:c25:f00a:c059
912c19:dd:d9:dd:c25:c25:f00a:c05a/1282c19:dd:d9:dd:c25:c25:f00a:c05a
922c19:dd:d9:dd:c25:c25:f00a:c05b/1282c19:dd:d9:dd:c25:c25:f00a:c05b
932c19:dd:d9:dd:c25:c25:f00a:c05c/1282c19:dd:d9:dd:c25:c25:f00a:c05c
942c19:dd:d9:dd:c25:c25:f00a:c05d/1282c19:dd:d9:dd:c25:c25:f00a:c05d
952c19:dd:d9:dd:c25:c25:f00a:c05e/1282c19:dd:d9:dd:c25:c25:f00a:c05e
962c19:dd:d9:dd:c25:c25:f00a:c05f/1282c19:dd:d9:dd:c25:c25:f00a:c05f
972c19:dd:d9:dd:c25:c25:f00a:c060/1282c19:dd:d9:dd:c25:c25:f00a:c060
982c19:dd:d9:dd:c25:c25:f00a:c061/1282c19:dd:d9:dd:c25:c25:f00a:c061
992c19:dd:d9:dd:c25:c25:f00a:c062/1282c19:dd:d9:dd:c25:c25:f00a:c062
1002c19:dd:d9:dd:c25:c25:f00a:c063/1282c19:dd:d9:dd:c25:c25:f00a:c063
1012c19:dd:d9:dd:c25:c25:f00a:c064/1282c19:dd:d9:dd:c25:c25:f00a:c064
1022c19:dd:d9:dd:c25:c25:f00a:c065/1282c19:dd:d9:dd:c25:c25:f00a:c065
1032c19:dd:d9:dd:c25:c25:f00a:c066/1282c19:dd:d9:dd:c25:c25:f00a:c066
1042c19:dd:d9:dd:c25:c25:f00a:c067/1282c19:dd:d9:dd:c25:c25:f00a:c067
1052c19:dd:d9:dd:c25:c25:f00a:c068/1282c19:dd:d9:dd:c25:c25:f00a:c068
1062c19:dd:d9:dd:c25:c25:f00a:c069/1282c19:dd:d9:dd:c25:c25:f00a:c069
1072c19:dd:d9:dd:c25:c25:f00a:c06a/1282c19:dd:d9:dd:c25:c25:f00a:c06a
1082c19:dd:d9:dd:c25:c25:f00a:c06b/1282c19:dd:d9:dd:c25:c25:f00a:c06b
1092c19:dd:d9:dd:c25:c25:f00a:c06c/1282c19:dd:d9:dd:c25:c25:f00a:c06c
1102c19:dd:d9:dd:c25:c25:f00a:c06d/1282c19:dd:d9:dd:c25:c25:f00a:c06d
1112c19:dd:d9:dd:c25:c25:f00a:c06e/1282c19:dd:d9:dd:c25:c25:f00a:c06e
1122c19:dd:d9:dd:c25:c25:f00a:c06f/1282c19:dd:d9:dd:c25:c25:f00a:c06f
1132c19:dd:d9:dd:c25:c25:f00a:c070/1282c19:dd:d9:dd:c25:c25:f00a:c070
1142c19:dd:d9:dd:c25:c25:f00a:c071/1282c19:dd:d9:dd:c25:c25:f00a:c071
1152c19:dd:d9:dd:c25:c25:f00a:c072/1282c19:dd:d9:dd:c25:c25:f00a:c072
1162c19:dd:d9:dd:c25:c25:f00a:c073/1282c19:dd:d9:dd:c25:c25:f00a:c073
1172c19:dd:d9:dd:c25:c25:f00a:c074/1282c19:dd:d9:dd:c25:c25:f00a:c074
1182c19:dd:d9:dd:c25:c25:f00a:c075/1282c19:dd:d9:dd:c25:c25:f00a:c075
1192c19:dd:d9:dd:c25:c25:f00a:c076/1282c19:dd:d9:dd:c25:c25:f00a:c076
1202c19:dd:d9:dd:c25:c25:f00a:c077/1282c19:dd:d9:dd:c25:c25:f00a:c077
1212c19:dd:d9:dd:c25:c25:f00a:c078/1282c19:dd:d9:dd:c25:c25:f00a:c078
1222c19:dd:d9:dd:c25:c25:f00a:c079/1282c19:dd:d9:dd:c25:c25:f00a:c079
1232c19:dd:d9:dd:c25:c25:f00a:c07a/1282c19:dd:d9:dd:c25:c25:f00a:c07a
1242c19:dd:d9:dd:c25:c25:f00a:c07b/1282c19:dd:d9:dd:c25:c25:f00a:c07b
1252c19:dd:d9:dd:c25:c25:f00a:c07c/1282c19:dd:d9:dd:c25:c25:f00a:c07c
1262c19:dd:d9:dd:c25:c25:f00a:c07d/1282c19:dd:d9:dd:c25:c25:f00a:c07d
1272c19:dd:d9:dd:c25:c25:f00a:c07e/1282c19:dd:d9:dd:c25:c25:f00a:c07e
1282c19:dd:d9:dd:c25:c25:f00a:c07f/1282c19:dd:d9:dd:c25:c25:f00a:c07f
1292c19:dd:d9:dd:c25:c25:f00a:c080/1282c19:dd:d9:dd:c25:c25:f00a:c080
1302c19:dd:d9:dd:c25:c25:f00a:c081/1282c19:dd:d9:dd:c25:c25:f00a:c081
1312c19:dd:d9:dd:c25:c25:f00a:c082/1282c19:dd:d9:dd:c25:c25:f00a:c082
1322c19:dd:d9:dd:c25:c25:f00a:c083/1282c19:dd:d9:dd:c25:c25:f00a:c083
1332c19:dd:d9:dd:c25:c25:f00a:c084/1282c19:dd:d9:dd:c25:c25:f00a:c084
1342c19:dd:d9:dd:c25:c25:f00a:c085/1282c19:dd:d9:dd:c25:c25:f00a:c085
1352c19:dd:d9:dd:c25:c25:f00a:c086/1282c19:dd:d9:dd:c25:c25:f00a:c086
1362c19:dd:d9:dd:c25:c25:f00a:c087/1282c19:dd:d9:dd:c25:c25:f00a:c087
1372c19:dd:d9:dd:c25:c25:f00a:c088/1282c19:dd:d9:dd:c25:c25:f00a:c088
1382c19:dd:d9:dd:c25:c25:f00a:c089/1282c19:dd:d9:dd:c25:c25:f00a:c089
1392c19:dd:d9:dd:c25:c25:f00a:c08a/1282c19:dd:d9:dd:c25:c25:f00a:c08a
1402c19:dd:d9:dd:c25:c25:f00a:c08b/1282c19:dd:d9:dd:c25:c25:f00a:c08b
1412c19:dd:d9:dd:c25:c25:f00a:c08c/1282c19:dd:d9:dd:c25:c25:f00a:c08c
1422c19:dd:d9:dd:c25:c25:f00a:c08d/1282c19:dd:d9:dd:c25:c25:f00a:c08d
1432c19:dd:d9:dd:c25:c25:f00a:c08e/1282c19:dd:d9:dd:c25:c25:f00a:c08e
1442c19:dd:d9:dd:c25:c25:f00a:c08f/1282c19:dd:d9:dd:c25:c25:f00a:c08f
1452c19:dd:d9:dd:c25:c25:f00a:c090/1282c19:dd:d9:dd:c25:c25:f00a:c090
1462c19:dd:d9:dd:c25:c25:f00a:c091/1282c19:dd:d9:dd:c25:c25:f00a:c091
1472c19:dd:d9:dd:c25:c25:f00a:c092/1282c19:dd:d9:dd:c25:c25:f00a:c092
1482c19:dd:d9:dd:c25:c25:f00a:c093/1282c19:dd:d9:dd:c25:c25:f00a:c093
1492c19:dd:d9:dd:c25:c25:f00a:c094/1282c19:dd:d9:dd:c25:c25:f00a:c094
1502c19:dd:d9:dd:c25:c25:f00a:c095/1282c19:dd:d9:dd:c25:c25:f00a:c095
1512c19:dd:d9:dd:c25:c25:f00a:c096/1282c19:dd:d9:dd:c25:c25:f00a:c096
1522c19:dd:d9:dd:c25:c25:f00a:c097/1282c19:dd:d9:dd:c25:c25:f00a:c097
1532c19:dd:d9:dd:c25:c25:f00a:c098/1282c19:dd:d9:dd:c25:c25:f00a:c098
1542c19:dd:d9:dd:c25:c25:f00a:c099/1282c19:dd:d9:dd:c25:c25:f00a:c099
1552c19:dd:d9:dd:c25:c25:f00a:c09a/1282c19:dd:d9:dd:c25:c25:f00a:c09a
1562c19:dd:d9:dd:c25:c25:f00a:c09b/1282c19:dd:d9:dd:c25:c25:f00a:c09b
1572c19:dd:d9:dd:c25:c25:f00a:c09c/1282c19:dd:d9:dd:c25:c25:f00a:c09c
1582c19:dd:d9:dd:c25:c25:f00a:c09d/1282c19:dd:d9:dd:c25:c25:f00a:c09d
1592c19:dd:d9:dd:c25:c25:f00a:c09e/1282c19:dd:d9:dd:c25:c25:f00a:c09e
1602c19:dd:d9:dd:c25:c25:f00a:c09f/1282c19:dd:d9:dd:c25:c25:f00a:c09f
1612c19:dd:d9:dd:c25:c25:f00a:c0a0/1282c19:dd:d9:dd:c25:c25:f00a:c0a0
1622c19:dd:d9:dd:c25:c25:f00a:c0a1/1282c19:dd:d9:dd:c25:c25:f00a:c0a1
1632c19:dd:d9:dd:c25:c25:f00a:c0a2/1282c19:dd:d9:dd:c25:c25:f00a:c0a2
1642c19:dd:d9:dd:c25:c25:f00a:c0a3/1282c19:dd:d9:dd:c25:c25:f00a:c0a3
1652c19:dd:d9:dd:c25:c25:f00a:c0a4/1282c19:dd:d9:dd:c25:c25:f00a:c0a4
1662c19:dd:d9:dd:c25:c25:f00a:c0a5/1282c19:dd:d9:dd:c25:c25:f00a:c0a5
1672c19:dd:d9:dd:c25:c25:f00a:c0a6/1282c19:dd:d9:dd:c25:c25:f00a:c0a6
1682c19:dd:d9:dd:c25:c25:f00a:c0a7/1282c19:dd:d9:dd:c25:c25:f00a:c0a7
1692c19:dd:d9:dd:c25:c25:f00a:c0a8/1282c19:dd:d9:dd:c25:c25:f00a:c0a8
1702c19:dd:d9:dd:c25:c25:f00a:c0a9/1282c19:dd:d9:dd:c25:c25:f00a:c0a9
1712c19:dd:d9:dd:c25:c25:f00a:c0aa/1282c19:dd:d9:dd:c25:c25:f00a:c0aa
1722c19:dd:d9:dd:c25:c25:f00a:c0ab/1282c19:dd:d9:dd:c25:c25:f00a:c0ab
1732c19:dd:d9:dd:c25:c25:f00a:c0ac/1282c19:dd:d9:dd:c25:c25:f00a:c0ac
1742c19:dd:d9:dd:c25:c25:f00a:c0ad/1282c19:dd:d9:dd:c25:c25:f00a:c0ad
1752c19:dd:d9:dd:c25:c25:f00a:c0ae/1282c19:dd:d9:dd:c25:c25:f00a:c0ae
1762c19:dd:d9:dd:c25:c25:f00a:c0af/1282c19:dd:d9:dd:c25:c25:f00a:c0af
1772c19:dd:d9:dd:c25:c25:f00a:c0b0/1282c19:dd:d9:dd:c25:c25:f00a:c0b0
1782c19:dd:d9:dd:c25:c25:f00a:c0b1/1282c19:dd:d9:dd:c25:c25:f00a:c0b1
1792c19:dd:d9:dd:c25:c25:f00a:c0b2/1282c19:dd:d9:dd:c25:c25:f00a:c0b2
1802c19:dd:d9:dd:c25:c25:f00a:c0b3/1282c19:dd:d9:dd:c25:c25:f00a:c0b3
1812c19:dd:d9:dd:c25:c25:f00a:c0b4/1282c19:dd:d9:dd:c25:c25:f00a:c0b4
1822c19:dd:d9:dd:c25:c25:f00a:c0b5/1282c19:dd:d9:dd:c25:c25:f00a:c0b5
1832c19:dd:d9:dd:c25:c25:f00a:c0b6/1282c19:dd:d9:dd:c25:c25:f00a:c0b6
1842c19:dd:d9:dd:c25:c25:f00a:c0b7/1282c19:dd:d9:dd:c25:c25:f00a:c0b7
1852c19:dd:d9:dd:c25:c25:f00a:c0b8/1282c19:dd:d9:dd:c25:c25:f00a:c0b8
1862c19:dd:d9:dd:c25:c25:f00a:c0b9/1282c19:dd:d9:dd:c25:c25:f00a:c0b9
1872c19:dd:d9:dd:c25:c25:f00a:c0ba/1282c19:dd:d9:dd:c25:c25:f00a:c0ba
1882c19:dd:d9:dd:c25:c25:f00a:c0bb/1282c19:dd:d9:dd:c25:c25:f00a:c0bb
1892c19:dd:d9:dd:c25:c25:f00a:c0bc/1282c19:dd:d9:dd:c25:c25:f00a:c0bc
1902c19:dd:d9:dd:c25:c25:f00a:c0bd/1282c19:dd:d9:dd:c25:c25:f00a:c0bd
1912c19:dd:d9:dd:c25:c25:f00a:c0be/1282c19:dd:d9:dd:c25:c25:f00a:c0be
1922c19:dd:d9:dd:c25:c25:f00a:c0bf/1282c19:dd:d9:dd:c25:c25:f00a:c0bf
1932c19:dd:d9:dd:c25:c25:f00a:c0c0/1282c19:dd:d9:dd:c25:c25:f00a:c0c0
1942c19:dd:d9:dd:c25:c25:f00a:c0c1/1282c19:dd:d9:dd:c25:c25:f00a:c0c1
1952c19:dd:d9:dd:c25:c25:f00a:c0c2/1282c19:dd:d9:dd:c25:c25:f00a:c0c2
1962c19:dd:d9:dd:c25:c25:f00a:c0c3/1282c19:dd:d9:dd:c25:c25:f00a:c0c3
1972c19:dd:d9:dd:c25:c25:f00a:c0c4/1282c19:dd:d9:dd:c25:c25:f00a:c0c4
1982c19:dd:d9:dd:c25:c25:f00a:c0c5/1282c19:dd:d9:dd:c25:c25:f00a:c0c5
1992c19:dd:d9:dd:c25:c25:f00a:c0c6/1282c19:dd:d9:dd:c25:c25:f00a:c0c6
2002c19:dd:d9:dd:c25:c25:f00a:c0c7/1282c19:dd:d9:dd:c25:c25:f00a:c0c7
2012c19:dd:d9:dd:c25:c25:f00a:c0c8/1282c19:dd:d9:dd:c25:c25:f00a:c0c8
2022c19:dd:d9:dd:c25:c25:f00a:c0c9/1282c19:dd:d9:dd:c25:c25:f00a:c0c9
2032c19:dd:d9:dd:c25:c25:f00a:c0ca/1282c19:dd:d9:dd:c25:c25:f00a:c0ca
2042c19:dd:d9:dd:c25:c25:f00a:c0cb/1282c19:dd:d9:dd:c25:c25:f00a:c0cb
2052c19:dd:d9:dd:c25:c25:f00a:c0cc/1282c19:dd:d9:dd:c25:c25:f00a:c0cc
2062c19:dd:d9:dd:c25:c25:f00a:c0cd/1282c19:dd:d9:dd:c25:c25:f00a:c0cd
2072c19:dd:d9:dd:c25:c25:f00a:c0ce/1282c19:dd:d9:dd:c25:c25:f00a:c0ce
2082c19:dd:d9:dd:c25:c25:f00a:c0cf/1282c19:dd:d9:dd:c25:c25:f00a:c0cf
2092c19:dd:d9:dd:c25:c25:f00a:c0d0/1282c19:dd:d9:dd:c25:c25:f00a:c0d0
2102c19:dd:d9:dd:c25:c25:f00a:c0d1/1282c19:dd:d9:dd:c25:c25:f00a:c0d1
2112c19:dd:d9:dd:c25:c25:f00a:c0d2/1282c19:dd:d9:dd:c25:c25:f00a:c0d2
2122c19:dd:d9:dd:c25:c25:f00a:c0d3/1282c19:dd:d9:dd:c25:c25:f00a:c0d3
2132c19:dd:d9:dd:c25:c25:f00a:c0d4/1282c19:dd:d9:dd:c25:c25:f00a:c0d4
2142c19:dd:d9:dd:c25:c25:f00a:c0d5/1282c19:dd:d9:dd:c25:c25:f00a:c0d5
2152c19:dd:d9:dd:c25:c25:f00a:c0d6/1282c19:dd:d9:dd:c25:c25:f00a:c0d6
2162c19:dd:d9:dd:c25:c25:f00a:c0d7/1282c19:dd:d9:dd:c25:c25:f00a:c0d7
2172c19:dd:d9:dd:c25:c25:f00a:c0d8/1282c19:dd:d9:dd:c25:c25:f00a:c0d8
2182c19:dd:d9:dd:c25:c25:f00a:c0d9/1282c19:dd:d9:dd:c25:c25:f00a:c0d9
2192c19:dd:d9:dd:c25:c25:f00a:c0da/1282c19:dd:d9:dd:c25:c25:f00a:c0da
2202c19:dd:d9:dd:c25:c25:f00a:c0db/1282c19:dd:d9:dd:c25:c25:f00a:c0db
2212c19:dd:d9:dd:c25:c25:f00a:c0dc/1282c19:dd:d9:dd:c25:c25:f00a:c0dc
2222c19:dd:d9:dd:c25:c25:f00a:c0dd/1282c19:dd:d9:dd:c25:c25:f00a:c0dd
2232c19:dd:d9:dd:c25:c25:f00a:c0de/1282c19:dd:d9:dd:c25:c25:f00a:c0de
2242c19:dd:d9:dd:c25:c25:f00a:c0df/1282c19:dd:d9:dd:c25:c25:f00a:c0df
2252c19:dd:d9:dd:c25:c25:f00a:c0e0/1282c19:dd:d9:dd:c25:c25:f00a:c0e0
2262c19:dd:d9:dd:c25:c25:f00a:c0e1/1282c19:dd:d9:dd:c25:c25:f00a:c0e1
2272c19:dd:d9:dd:c25:c25:f00a:c0e2/1282c19:dd:d9:dd:c25:c25:f00a:c0e2
2282c19:dd:d9:dd:c25:c25:f00a:c0e3/1282c19:dd:d9:dd:c25:c25:f00a:c0e3
2292c19:dd:d9:dd:c25:c25:f00a:c0e4/1282c19:dd:d9:dd:c25:c25:f00a:c0e4
2302c19:dd:d9:dd:c25:c25:f00a:c0e5/1282c19:dd:d9:dd:c25:c25:f00a:c0e5
2312c19:dd:d9:dd:c25:c25:f00a:c0e6/1282c19:dd:d9:dd:c25:c25:f00a:c0e6
2322c19:dd:d9:dd:c25:c25:f00a:c0e7/1282c19:dd:d9:dd:c25:c25:f00a:c0e7
2332c19:dd:d9:dd:c25:c25:f00a:c0e8/1282c19:dd:d9:dd:c25:c25:f00a:c0e8
2342c19:dd:d9:dd:c25:c25:f00a:c0e9/1282c19:dd:d9:dd:c25:c25:f00a:c0e9
2352c19:dd:d9:dd:c25:c25:f00a:c0ea/1282c19:dd:d9:dd:c25:c25:f00a:c0ea
2362c19:dd:d9:dd:c25:c25:f00a:c0eb/1282c19:dd:d9:dd:c25:c25:f00a:c0eb
2372c19:dd:d9:dd:c25:c25:f00a:c0ec/1282c19:dd:d9:dd:c25:c25:f00a:c0ec
2382c19:dd:d9:dd:c25:c25:f00a:c0ed/1282c19:dd:d9:dd:c25:c25:f00a:c0ed
2392c19:dd:d9:dd:c25:c25:f00a:c0ee/1282c19:dd:d9:dd:c25:c25:f00a:c0ee
2402c19:dd:d9:dd:c25:c25:f00a:c0ef/1282c19:dd:d9:dd:c25:c25:f00a:c0ef
2412c19:dd:d9:dd:c25:c25:f00a:c0f0/1282c19:dd:d9:dd:c25:c25:f00a:c0f0
2422c19:dd:d9:dd:c25:c25:f00a:c0f1/1282c19:dd:d9:dd:c25:c25:f00a:c0f1
2432c19:dd:d9:dd:c25:c25:f00a:c0f2/1282c19:dd:d9:dd:c25:c25:f00a:c0f2
2442c19:dd:d9:dd:c25:c25:f00a:c0f3/1282c19:dd:d9:dd:c25:c25:f00a:c0f3
2452c19:dd:d9:dd:c25:c25:f00a:c0f4/1282c19:dd:d9:dd:c25:c25:f00a:c0f4
2462c19:dd:d9:dd:c25:c25:f00a:c0f5/1282c19:dd:d9:dd:c25:c25:f00a:c0f5
2472c19:dd:d9:dd:c25:c25:f00a:c0f6/1282c19:dd:d9:dd:c25:c25:f00a:c0f6
2482c19:dd:d9:dd:c25:c25:f00a:c0f7/1282c19:dd:d9:dd:c25:c25:f00a:c0f7
2492c19:dd:d9:dd:c25:c25:f00a:c0f8/1282c19:dd:d9:dd:c25:c25:f00a:c0f8
2502c19:dd:d9:dd:c25:c25:f00a:c0f9/1282c19:dd:d9:dd:c25:c25:f00a:c0f9
2512c19:dd:d9:dd:c25:c25:f00a:c0fa/1282c19:dd:d9:dd:c25:c25:f00a:c0fa
2522c19:dd:d9:dd:c25:c25:f00a:c0fb/1282c19:dd:d9:dd:c25:c25:f00a:c0fb
2532c19:dd:d9:dd:c25:c25:f00a:c0fc/1282c19:dd:d9:dd:c25:c25:f00a:c0fc
2542c19:dd:d9:dd:c25:c25:f00a:c0fd/1282c19:dd:d9:dd:c25:c25:f00a:c0fd
2552c19:dd:d9:dd:c25:c25:f00a:c0fe/1282c19:dd:d9:dd:c25:c25:f00a:c0fe
2562c19:dd:d9:dd:c25:c25:f00a:c0ff/1282c19:dd:d9:dd:c25:c25:f00a:c0ff

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.