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/120
Addresses256
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:d915:7000/120
First address
2c19:dd:d9:dd:c25:c25:d915:7000
Last address
2c19:dd:d9:dd:c25:c25:d915:70ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:d915:7000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
0.7.5.1.9.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
Split into smaller subnets/128
/121 (2)/122 (4)/123 (8)/124 (16)/127 (128)/128 (256)

2c19:dd:d9:dd:c25:c25:d915:7000/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:d915:7000/1282c19:dd:d9:dd:c25:c25:d915:7000
22c19:dd:d9:dd:c25:c25:d915:7001/1282c19:dd:d9:dd:c25:c25:d915:7001
32c19:dd:d9:dd:c25:c25:d915:7002/1282c19:dd:d9:dd:c25:c25:d915:7002
42c19:dd:d9:dd:c25:c25:d915:7003/1282c19:dd:d9:dd:c25:c25:d915:7003
52c19:dd:d9:dd:c25:c25:d915:7004/1282c19:dd:d9:dd:c25:c25:d915:7004
62c19:dd:d9:dd:c25:c25:d915:7005/1282c19:dd:d9:dd:c25:c25:d915:7005
72c19:dd:d9:dd:c25:c25:d915:7006/1282c19:dd:d9:dd:c25:c25:d915:7006
82c19:dd:d9:dd:c25:c25:d915:7007/1282c19:dd:d9:dd:c25:c25:d915:7007
92c19:dd:d9:dd:c25:c25:d915:7008/1282c19:dd:d9:dd:c25:c25:d915:7008
102c19:dd:d9:dd:c25:c25:d915:7009/1282c19:dd:d9:dd:c25:c25:d915:7009
112c19:dd:d9:dd:c25:c25:d915:700a/1282c19:dd:d9:dd:c25:c25:d915:700a
122c19:dd:d9:dd:c25:c25:d915:700b/1282c19:dd:d9:dd:c25:c25:d915:700b
132c19:dd:d9:dd:c25:c25:d915:700c/1282c19:dd:d9:dd:c25:c25:d915:700c
142c19:dd:d9:dd:c25:c25:d915:700d/1282c19:dd:d9:dd:c25:c25:d915:700d
152c19:dd:d9:dd:c25:c25:d915:700e/1282c19:dd:d9:dd:c25:c25:d915:700e
162c19:dd:d9:dd:c25:c25:d915:700f/1282c19:dd:d9:dd:c25:c25:d915:700f
172c19:dd:d9:dd:c25:c25:d915:7010/1282c19:dd:d9:dd:c25:c25:d915:7010
182c19:dd:d9:dd:c25:c25:d915:7011/1282c19:dd:d9:dd:c25:c25:d915:7011
192c19:dd:d9:dd:c25:c25:d915:7012/1282c19:dd:d9:dd:c25:c25:d915:7012
202c19:dd:d9:dd:c25:c25:d915:7013/1282c19:dd:d9:dd:c25:c25:d915:7013
212c19:dd:d9:dd:c25:c25:d915:7014/1282c19:dd:d9:dd:c25:c25:d915:7014
222c19:dd:d9:dd:c25:c25:d915:7015/1282c19:dd:d9:dd:c25:c25:d915:7015
232c19:dd:d9:dd:c25:c25:d915:7016/1282c19:dd:d9:dd:c25:c25:d915:7016
242c19:dd:d9:dd:c25:c25:d915:7017/1282c19:dd:d9:dd:c25:c25:d915:7017
252c19:dd:d9:dd:c25:c25:d915:7018/1282c19:dd:d9:dd:c25:c25:d915:7018
262c19:dd:d9:dd:c25:c25:d915:7019/1282c19:dd:d9:dd:c25:c25:d915:7019
272c19:dd:d9:dd:c25:c25:d915:701a/1282c19:dd:d9:dd:c25:c25:d915:701a
282c19:dd:d9:dd:c25:c25:d915:701b/1282c19:dd:d9:dd:c25:c25:d915:701b
292c19:dd:d9:dd:c25:c25:d915:701c/1282c19:dd:d9:dd:c25:c25:d915:701c
302c19:dd:d9:dd:c25:c25:d915:701d/1282c19:dd:d9:dd:c25:c25:d915:701d
312c19:dd:d9:dd:c25:c25:d915:701e/1282c19:dd:d9:dd:c25:c25:d915:701e
322c19:dd:d9:dd:c25:c25:d915:701f/1282c19:dd:d9:dd:c25:c25:d915:701f
332c19:dd:d9:dd:c25:c25:d915:7020/1282c19:dd:d9:dd:c25:c25:d915:7020
342c19:dd:d9:dd:c25:c25:d915:7021/1282c19:dd:d9:dd:c25:c25:d915:7021
352c19:dd:d9:dd:c25:c25:d915:7022/1282c19:dd:d9:dd:c25:c25:d915:7022
362c19:dd:d9:dd:c25:c25:d915:7023/1282c19:dd:d9:dd:c25:c25:d915:7023
372c19:dd:d9:dd:c25:c25:d915:7024/1282c19:dd:d9:dd:c25:c25:d915:7024
382c19:dd:d9:dd:c25:c25:d915:7025/1282c19:dd:d9:dd:c25:c25:d915:7025
392c19:dd:d9:dd:c25:c25:d915:7026/1282c19:dd:d9:dd:c25:c25:d915:7026
402c19:dd:d9:dd:c25:c25:d915:7027/1282c19:dd:d9:dd:c25:c25:d915:7027
412c19:dd:d9:dd:c25:c25:d915:7028/1282c19:dd:d9:dd:c25:c25:d915:7028
422c19:dd:d9:dd:c25:c25:d915:7029/1282c19:dd:d9:dd:c25:c25:d915:7029
432c19:dd:d9:dd:c25:c25:d915:702a/1282c19:dd:d9:dd:c25:c25:d915:702a
442c19:dd:d9:dd:c25:c25:d915:702b/1282c19:dd:d9:dd:c25:c25:d915:702b
452c19:dd:d9:dd:c25:c25:d915:702c/1282c19:dd:d9:dd:c25:c25:d915:702c
462c19:dd:d9:dd:c25:c25:d915:702d/1282c19:dd:d9:dd:c25:c25:d915:702d
472c19:dd:d9:dd:c25:c25:d915:702e/1282c19:dd:d9:dd:c25:c25:d915:702e
482c19:dd:d9:dd:c25:c25:d915:702f/1282c19:dd:d9:dd:c25:c25:d915:702f
492c19:dd:d9:dd:c25:c25:d915:7030/1282c19:dd:d9:dd:c25:c25:d915:7030
502c19:dd:d9:dd:c25:c25:d915:7031/1282c19:dd:d9:dd:c25:c25:d915:7031
512c19:dd:d9:dd:c25:c25:d915:7032/1282c19:dd:d9:dd:c25:c25:d915:7032
522c19:dd:d9:dd:c25:c25:d915:7033/1282c19:dd:d9:dd:c25:c25:d915:7033
532c19:dd:d9:dd:c25:c25:d915:7034/1282c19:dd:d9:dd:c25:c25:d915:7034
542c19:dd:d9:dd:c25:c25:d915:7035/1282c19:dd:d9:dd:c25:c25:d915:7035
552c19:dd:d9:dd:c25:c25:d915:7036/1282c19:dd:d9:dd:c25:c25:d915:7036
562c19:dd:d9:dd:c25:c25:d915:7037/1282c19:dd:d9:dd:c25:c25:d915:7037
572c19:dd:d9:dd:c25:c25:d915:7038/1282c19:dd:d9:dd:c25:c25:d915:7038
582c19:dd:d9:dd:c25:c25:d915:7039/1282c19:dd:d9:dd:c25:c25:d915:7039
592c19:dd:d9:dd:c25:c25:d915:703a/1282c19:dd:d9:dd:c25:c25:d915:703a
602c19:dd:d9:dd:c25:c25:d915:703b/1282c19:dd:d9:dd:c25:c25:d915:703b
612c19:dd:d9:dd:c25:c25:d915:703c/1282c19:dd:d9:dd:c25:c25:d915:703c
622c19:dd:d9:dd:c25:c25:d915:703d/1282c19:dd:d9:dd:c25:c25:d915:703d
632c19:dd:d9:dd:c25:c25:d915:703e/1282c19:dd:d9:dd:c25:c25:d915:703e
642c19:dd:d9:dd:c25:c25:d915:703f/1282c19:dd:d9:dd:c25:c25:d915:703f
652c19:dd:d9:dd:c25:c25:d915:7040/1282c19:dd:d9:dd:c25:c25:d915:7040
662c19:dd:d9:dd:c25:c25:d915:7041/1282c19:dd:d9:dd:c25:c25:d915:7041
672c19:dd:d9:dd:c25:c25:d915:7042/1282c19:dd:d9:dd:c25:c25:d915:7042
682c19:dd:d9:dd:c25:c25:d915:7043/1282c19:dd:d9:dd:c25:c25:d915:7043
692c19:dd:d9:dd:c25:c25:d915:7044/1282c19:dd:d9:dd:c25:c25:d915:7044
702c19:dd:d9:dd:c25:c25:d915:7045/1282c19:dd:d9:dd:c25:c25:d915:7045
712c19:dd:d9:dd:c25:c25:d915:7046/1282c19:dd:d9:dd:c25:c25:d915:7046
722c19:dd:d9:dd:c25:c25:d915:7047/1282c19:dd:d9:dd:c25:c25:d915:7047
732c19:dd:d9:dd:c25:c25:d915:7048/1282c19:dd:d9:dd:c25:c25:d915:7048
742c19:dd:d9:dd:c25:c25:d915:7049/1282c19:dd:d9:dd:c25:c25:d915:7049
752c19:dd:d9:dd:c25:c25:d915:704a/1282c19:dd:d9:dd:c25:c25:d915:704a
762c19:dd:d9:dd:c25:c25:d915:704b/1282c19:dd:d9:dd:c25:c25:d915:704b
772c19:dd:d9:dd:c25:c25:d915:704c/1282c19:dd:d9:dd:c25:c25:d915:704c
782c19:dd:d9:dd:c25:c25:d915:704d/1282c19:dd:d9:dd:c25:c25:d915:704d
792c19:dd:d9:dd:c25:c25:d915:704e/1282c19:dd:d9:dd:c25:c25:d915:704e
802c19:dd:d9:dd:c25:c25:d915:704f/1282c19:dd:d9:dd:c25:c25:d915:704f
812c19:dd:d9:dd:c25:c25:d915:7050/1282c19:dd:d9:dd:c25:c25:d915:7050
822c19:dd:d9:dd:c25:c25:d915:7051/1282c19:dd:d9:dd:c25:c25:d915:7051
832c19:dd:d9:dd:c25:c25:d915:7052/1282c19:dd:d9:dd:c25:c25:d915:7052
842c19:dd:d9:dd:c25:c25:d915:7053/1282c19:dd:d9:dd:c25:c25:d915:7053
852c19:dd:d9:dd:c25:c25:d915:7054/1282c19:dd:d9:dd:c25:c25:d915:7054
862c19:dd:d9:dd:c25:c25:d915:7055/1282c19:dd:d9:dd:c25:c25:d915:7055
872c19:dd:d9:dd:c25:c25:d915:7056/1282c19:dd:d9:dd:c25:c25:d915:7056
882c19:dd:d9:dd:c25:c25:d915:7057/1282c19:dd:d9:dd:c25:c25:d915:7057
892c19:dd:d9:dd:c25:c25:d915:7058/1282c19:dd:d9:dd:c25:c25:d915:7058
902c19:dd:d9:dd:c25:c25:d915:7059/1282c19:dd:d9:dd:c25:c25:d915:7059
912c19:dd:d9:dd:c25:c25:d915:705a/1282c19:dd:d9:dd:c25:c25:d915:705a
922c19:dd:d9:dd:c25:c25:d915:705b/1282c19:dd:d9:dd:c25:c25:d915:705b
932c19:dd:d9:dd:c25:c25:d915:705c/1282c19:dd:d9:dd:c25:c25:d915:705c
942c19:dd:d9:dd:c25:c25:d915:705d/1282c19:dd:d9:dd:c25:c25:d915:705d
952c19:dd:d9:dd:c25:c25:d915:705e/1282c19:dd:d9:dd:c25:c25:d915:705e
962c19:dd:d9:dd:c25:c25:d915:705f/1282c19:dd:d9:dd:c25:c25:d915:705f
972c19:dd:d9:dd:c25:c25:d915:7060/1282c19:dd:d9:dd:c25:c25:d915:7060
982c19:dd:d9:dd:c25:c25:d915:7061/1282c19:dd:d9:dd:c25:c25:d915:7061
992c19:dd:d9:dd:c25:c25:d915:7062/1282c19:dd:d9:dd:c25:c25:d915:7062
1002c19:dd:d9:dd:c25:c25:d915:7063/1282c19:dd:d9:dd:c25:c25:d915:7063
1012c19:dd:d9:dd:c25:c25:d915:7064/1282c19:dd:d9:dd:c25:c25:d915:7064
1022c19:dd:d9:dd:c25:c25:d915:7065/1282c19:dd:d9:dd:c25:c25:d915:7065
1032c19:dd:d9:dd:c25:c25:d915:7066/1282c19:dd:d9:dd:c25:c25:d915:7066
1042c19:dd:d9:dd:c25:c25:d915:7067/1282c19:dd:d9:dd:c25:c25:d915:7067
1052c19:dd:d9:dd:c25:c25:d915:7068/1282c19:dd:d9:dd:c25:c25:d915:7068
1062c19:dd:d9:dd:c25:c25:d915:7069/1282c19:dd:d9:dd:c25:c25:d915:7069
1072c19:dd:d9:dd:c25:c25:d915:706a/1282c19:dd:d9:dd:c25:c25:d915:706a
1082c19:dd:d9:dd:c25:c25:d915:706b/1282c19:dd:d9:dd:c25:c25:d915:706b
1092c19:dd:d9:dd:c25:c25:d915:706c/1282c19:dd:d9:dd:c25:c25:d915:706c
1102c19:dd:d9:dd:c25:c25:d915:706d/1282c19:dd:d9:dd:c25:c25:d915:706d
1112c19:dd:d9:dd:c25:c25:d915:706e/1282c19:dd:d9:dd:c25:c25:d915:706e
1122c19:dd:d9:dd:c25:c25:d915:706f/1282c19:dd:d9:dd:c25:c25:d915:706f
1132c19:dd:d9:dd:c25:c25:d915:7070/1282c19:dd:d9:dd:c25:c25:d915:7070
1142c19:dd:d9:dd:c25:c25:d915:7071/1282c19:dd:d9:dd:c25:c25:d915:7071
1152c19:dd:d9:dd:c25:c25:d915:7072/1282c19:dd:d9:dd:c25:c25:d915:7072
1162c19:dd:d9:dd:c25:c25:d915:7073/1282c19:dd:d9:dd:c25:c25:d915:7073
1172c19:dd:d9:dd:c25:c25:d915:7074/1282c19:dd:d9:dd:c25:c25:d915:7074
1182c19:dd:d9:dd:c25:c25:d915:7075/1282c19:dd:d9:dd:c25:c25:d915:7075
1192c19:dd:d9:dd:c25:c25:d915:7076/1282c19:dd:d9:dd:c25:c25:d915:7076
1202c19:dd:d9:dd:c25:c25:d915:7077/1282c19:dd:d9:dd:c25:c25:d915:7077
1212c19:dd:d9:dd:c25:c25:d915:7078/1282c19:dd:d9:dd:c25:c25:d915:7078
1222c19:dd:d9:dd:c25:c25:d915:7079/1282c19:dd:d9:dd:c25:c25:d915:7079
1232c19:dd:d9:dd:c25:c25:d915:707a/1282c19:dd:d9:dd:c25:c25:d915:707a
1242c19:dd:d9:dd:c25:c25:d915:707b/1282c19:dd:d9:dd:c25:c25:d915:707b
1252c19:dd:d9:dd:c25:c25:d915:707c/1282c19:dd:d9:dd:c25:c25:d915:707c
1262c19:dd:d9:dd:c25:c25:d915:707d/1282c19:dd:d9:dd:c25:c25:d915:707d
1272c19:dd:d9:dd:c25:c25:d915:707e/1282c19:dd:d9:dd:c25:c25:d915:707e
1282c19:dd:d9:dd:c25:c25:d915:707f/1282c19:dd:d9:dd:c25:c25:d915:707f
1292c19:dd:d9:dd:c25:c25:d915:7080/1282c19:dd:d9:dd:c25:c25:d915:7080
1302c19:dd:d9:dd:c25:c25:d915:7081/1282c19:dd:d9:dd:c25:c25:d915:7081
1312c19:dd:d9:dd:c25:c25:d915:7082/1282c19:dd:d9:dd:c25:c25:d915:7082
1322c19:dd:d9:dd:c25:c25:d915:7083/1282c19:dd:d9:dd:c25:c25:d915:7083
1332c19:dd:d9:dd:c25:c25:d915:7084/1282c19:dd:d9:dd:c25:c25:d915:7084
1342c19:dd:d9:dd:c25:c25:d915:7085/1282c19:dd:d9:dd:c25:c25:d915:7085
1352c19:dd:d9:dd:c25:c25:d915:7086/1282c19:dd:d9:dd:c25:c25:d915:7086
1362c19:dd:d9:dd:c25:c25:d915:7087/1282c19:dd:d9:dd:c25:c25:d915:7087
1372c19:dd:d9:dd:c25:c25:d915:7088/1282c19:dd:d9:dd:c25:c25:d915:7088
1382c19:dd:d9:dd:c25:c25:d915:7089/1282c19:dd:d9:dd:c25:c25:d915:7089
1392c19:dd:d9:dd:c25:c25:d915:708a/1282c19:dd:d9:dd:c25:c25:d915:708a
1402c19:dd:d9:dd:c25:c25:d915:708b/1282c19:dd:d9:dd:c25:c25:d915:708b
1412c19:dd:d9:dd:c25:c25:d915:708c/1282c19:dd:d9:dd:c25:c25:d915:708c
1422c19:dd:d9:dd:c25:c25:d915:708d/1282c19:dd:d9:dd:c25:c25:d915:708d
1432c19:dd:d9:dd:c25:c25:d915:708e/1282c19:dd:d9:dd:c25:c25:d915:708e
1442c19:dd:d9:dd:c25:c25:d915:708f/1282c19:dd:d9:dd:c25:c25:d915:708f
1452c19:dd:d9:dd:c25:c25:d915:7090/1282c19:dd:d9:dd:c25:c25:d915:7090
1462c19:dd:d9:dd:c25:c25:d915:7091/1282c19:dd:d9:dd:c25:c25:d915:7091
1472c19:dd:d9:dd:c25:c25:d915:7092/1282c19:dd:d9:dd:c25:c25:d915:7092
1482c19:dd:d9:dd:c25:c25:d915:7093/1282c19:dd:d9:dd:c25:c25:d915:7093
1492c19:dd:d9:dd:c25:c25:d915:7094/1282c19:dd:d9:dd:c25:c25:d915:7094
1502c19:dd:d9:dd:c25:c25:d915:7095/1282c19:dd:d9:dd:c25:c25:d915:7095
1512c19:dd:d9:dd:c25:c25:d915:7096/1282c19:dd:d9:dd:c25:c25:d915:7096
1522c19:dd:d9:dd:c25:c25:d915:7097/1282c19:dd:d9:dd:c25:c25:d915:7097
1532c19:dd:d9:dd:c25:c25:d915:7098/1282c19:dd:d9:dd:c25:c25:d915:7098
1542c19:dd:d9:dd:c25:c25:d915:7099/1282c19:dd:d9:dd:c25:c25:d915:7099
1552c19:dd:d9:dd:c25:c25:d915:709a/1282c19:dd:d9:dd:c25:c25:d915:709a
1562c19:dd:d9:dd:c25:c25:d915:709b/1282c19:dd:d9:dd:c25:c25:d915:709b
1572c19:dd:d9:dd:c25:c25:d915:709c/1282c19:dd:d9:dd:c25:c25:d915:709c
1582c19:dd:d9:dd:c25:c25:d915:709d/1282c19:dd:d9:dd:c25:c25:d915:709d
1592c19:dd:d9:dd:c25:c25:d915:709e/1282c19:dd:d9:dd:c25:c25:d915:709e
1602c19:dd:d9:dd:c25:c25:d915:709f/1282c19:dd:d9:dd:c25:c25:d915:709f
1612c19:dd:d9:dd:c25:c25:d915:70a0/1282c19:dd:d9:dd:c25:c25:d915:70a0
1622c19:dd:d9:dd:c25:c25:d915:70a1/1282c19:dd:d9:dd:c25:c25:d915:70a1
1632c19:dd:d9:dd:c25:c25:d915:70a2/1282c19:dd:d9:dd:c25:c25:d915:70a2
1642c19:dd:d9:dd:c25:c25:d915:70a3/1282c19:dd:d9:dd:c25:c25:d915:70a3
1652c19:dd:d9:dd:c25:c25:d915:70a4/1282c19:dd:d9:dd:c25:c25:d915:70a4
1662c19:dd:d9:dd:c25:c25:d915:70a5/1282c19:dd:d9:dd:c25:c25:d915:70a5
1672c19:dd:d9:dd:c25:c25:d915:70a6/1282c19:dd:d9:dd:c25:c25:d915:70a6
1682c19:dd:d9:dd:c25:c25:d915:70a7/1282c19:dd:d9:dd:c25:c25:d915:70a7
1692c19:dd:d9:dd:c25:c25:d915:70a8/1282c19:dd:d9:dd:c25:c25:d915:70a8
1702c19:dd:d9:dd:c25:c25:d915:70a9/1282c19:dd:d9:dd:c25:c25:d915:70a9
1712c19:dd:d9:dd:c25:c25:d915:70aa/1282c19:dd:d9:dd:c25:c25:d915:70aa
1722c19:dd:d9:dd:c25:c25:d915:70ab/1282c19:dd:d9:dd:c25:c25:d915:70ab
1732c19:dd:d9:dd:c25:c25:d915:70ac/1282c19:dd:d9:dd:c25:c25:d915:70ac
1742c19:dd:d9:dd:c25:c25:d915:70ad/1282c19:dd:d9:dd:c25:c25:d915:70ad
1752c19:dd:d9:dd:c25:c25:d915:70ae/1282c19:dd:d9:dd:c25:c25:d915:70ae
1762c19:dd:d9:dd:c25:c25:d915:70af/1282c19:dd:d9:dd:c25:c25:d915:70af
1772c19:dd:d9:dd:c25:c25:d915:70b0/1282c19:dd:d9:dd:c25:c25:d915:70b0
1782c19:dd:d9:dd:c25:c25:d915:70b1/1282c19:dd:d9:dd:c25:c25:d915:70b1
1792c19:dd:d9:dd:c25:c25:d915:70b2/1282c19:dd:d9:dd:c25:c25:d915:70b2
1802c19:dd:d9:dd:c25:c25:d915:70b3/1282c19:dd:d9:dd:c25:c25:d915:70b3
1812c19:dd:d9:dd:c25:c25:d915:70b4/1282c19:dd:d9:dd:c25:c25:d915:70b4
1822c19:dd:d9:dd:c25:c25:d915:70b5/1282c19:dd:d9:dd:c25:c25:d915:70b5
1832c19:dd:d9:dd:c25:c25:d915:70b6/1282c19:dd:d9:dd:c25:c25:d915:70b6
1842c19:dd:d9:dd:c25:c25:d915:70b7/1282c19:dd:d9:dd:c25:c25:d915:70b7
1852c19:dd:d9:dd:c25:c25:d915:70b8/1282c19:dd:d9:dd:c25:c25:d915:70b8
1862c19:dd:d9:dd:c25:c25:d915:70b9/1282c19:dd:d9:dd:c25:c25:d915:70b9
1872c19:dd:d9:dd:c25:c25:d915:70ba/1282c19:dd:d9:dd:c25:c25:d915:70ba
1882c19:dd:d9:dd:c25:c25:d915:70bb/1282c19:dd:d9:dd:c25:c25:d915:70bb
1892c19:dd:d9:dd:c25:c25:d915:70bc/1282c19:dd:d9:dd:c25:c25:d915:70bc
1902c19:dd:d9:dd:c25:c25:d915:70bd/1282c19:dd:d9:dd:c25:c25:d915:70bd
1912c19:dd:d9:dd:c25:c25:d915:70be/1282c19:dd:d9:dd:c25:c25:d915:70be
1922c19:dd:d9:dd:c25:c25:d915:70bf/1282c19:dd:d9:dd:c25:c25:d915:70bf
1932c19:dd:d9:dd:c25:c25:d915:70c0/1282c19:dd:d9:dd:c25:c25:d915:70c0
1942c19:dd:d9:dd:c25:c25:d915:70c1/1282c19:dd:d9:dd:c25:c25:d915:70c1
1952c19:dd:d9:dd:c25:c25:d915:70c2/1282c19:dd:d9:dd:c25:c25:d915:70c2
1962c19:dd:d9:dd:c25:c25:d915:70c3/1282c19:dd:d9:dd:c25:c25:d915:70c3
1972c19:dd:d9:dd:c25:c25:d915:70c4/1282c19:dd:d9:dd:c25:c25:d915:70c4
1982c19:dd:d9:dd:c25:c25:d915:70c5/1282c19:dd:d9:dd:c25:c25:d915:70c5
1992c19:dd:d9:dd:c25:c25:d915:70c6/1282c19:dd:d9:dd:c25:c25:d915:70c6
2002c19:dd:d9:dd:c25:c25:d915:70c7/1282c19:dd:d9:dd:c25:c25:d915:70c7
2012c19:dd:d9:dd:c25:c25:d915:70c8/1282c19:dd:d9:dd:c25:c25:d915:70c8
2022c19:dd:d9:dd:c25:c25:d915:70c9/1282c19:dd:d9:dd:c25:c25:d915:70c9
2032c19:dd:d9:dd:c25:c25:d915:70ca/1282c19:dd:d9:dd:c25:c25:d915:70ca
2042c19:dd:d9:dd:c25:c25:d915:70cb/1282c19:dd:d9:dd:c25:c25:d915:70cb
2052c19:dd:d9:dd:c25:c25:d915:70cc/1282c19:dd:d9:dd:c25:c25:d915:70cc
2062c19:dd:d9:dd:c25:c25:d915:70cd/1282c19:dd:d9:dd:c25:c25:d915:70cd
2072c19:dd:d9:dd:c25:c25:d915:70ce/1282c19:dd:d9:dd:c25:c25:d915:70ce
2082c19:dd:d9:dd:c25:c25:d915:70cf/1282c19:dd:d9:dd:c25:c25:d915:70cf
2092c19:dd:d9:dd:c25:c25:d915:70d0/1282c19:dd:d9:dd:c25:c25:d915:70d0
2102c19:dd:d9:dd:c25:c25:d915:70d1/1282c19:dd:d9:dd:c25:c25:d915:70d1
2112c19:dd:d9:dd:c25:c25:d915:70d2/1282c19:dd:d9:dd:c25:c25:d915:70d2
2122c19:dd:d9:dd:c25:c25:d915:70d3/1282c19:dd:d9:dd:c25:c25:d915:70d3
2132c19:dd:d9:dd:c25:c25:d915:70d4/1282c19:dd:d9:dd:c25:c25:d915:70d4
2142c19:dd:d9:dd:c25:c25:d915:70d5/1282c19:dd:d9:dd:c25:c25:d915:70d5
2152c19:dd:d9:dd:c25:c25:d915:70d6/1282c19:dd:d9:dd:c25:c25:d915:70d6
2162c19:dd:d9:dd:c25:c25:d915:70d7/1282c19:dd:d9:dd:c25:c25:d915:70d7
2172c19:dd:d9:dd:c25:c25:d915:70d8/1282c19:dd:d9:dd:c25:c25:d915:70d8
2182c19:dd:d9:dd:c25:c25:d915:70d9/1282c19:dd:d9:dd:c25:c25:d915:70d9
2192c19:dd:d9:dd:c25:c25:d915:70da/1282c19:dd:d9:dd:c25:c25:d915:70da
2202c19:dd:d9:dd:c25:c25:d915:70db/1282c19:dd:d9:dd:c25:c25:d915:70db
2212c19:dd:d9:dd:c25:c25:d915:70dc/1282c19:dd:d9:dd:c25:c25:d915:70dc
2222c19:dd:d9:dd:c25:c25:d915:70dd/1282c19:dd:d9:dd:c25:c25:d915:70dd
2232c19:dd:d9:dd:c25:c25:d915:70de/1282c19:dd:d9:dd:c25:c25:d915:70de
2242c19:dd:d9:dd:c25:c25:d915:70df/1282c19:dd:d9:dd:c25:c25:d915:70df
2252c19:dd:d9:dd:c25:c25:d915:70e0/1282c19:dd:d9:dd:c25:c25:d915:70e0
2262c19:dd:d9:dd:c25:c25:d915:70e1/1282c19:dd:d9:dd:c25:c25:d915:70e1
2272c19:dd:d9:dd:c25:c25:d915:70e2/1282c19:dd:d9:dd:c25:c25:d915:70e2
2282c19:dd:d9:dd:c25:c25:d915:70e3/1282c19:dd:d9:dd:c25:c25:d915:70e3
2292c19:dd:d9:dd:c25:c25:d915:70e4/1282c19:dd:d9:dd:c25:c25:d915:70e4
2302c19:dd:d9:dd:c25:c25:d915:70e5/1282c19:dd:d9:dd:c25:c25:d915:70e5
2312c19:dd:d9:dd:c25:c25:d915:70e6/1282c19:dd:d9:dd:c25:c25:d915:70e6
2322c19:dd:d9:dd:c25:c25:d915:70e7/1282c19:dd:d9:dd:c25:c25:d915:70e7
2332c19:dd:d9:dd:c25:c25:d915:70e8/1282c19:dd:d9:dd:c25:c25:d915:70e8
2342c19:dd:d9:dd:c25:c25:d915:70e9/1282c19:dd:d9:dd:c25:c25:d915:70e9
2352c19:dd:d9:dd:c25:c25:d915:70ea/1282c19:dd:d9:dd:c25:c25:d915:70ea
2362c19:dd:d9:dd:c25:c25:d915:70eb/1282c19:dd:d9:dd:c25:c25:d915:70eb
2372c19:dd:d9:dd:c25:c25:d915:70ec/1282c19:dd:d9:dd:c25:c25:d915:70ec
2382c19:dd:d9:dd:c25:c25:d915:70ed/1282c19:dd:d9:dd:c25:c25:d915:70ed
2392c19:dd:d9:dd:c25:c25:d915:70ee/1282c19:dd:d9:dd:c25:c25:d915:70ee
2402c19:dd:d9:dd:c25:c25:d915:70ef/1282c19:dd:d9:dd:c25:c25:d915:70ef
2412c19:dd:d9:dd:c25:c25:d915:70f0/1282c19:dd:d9:dd:c25:c25:d915:70f0
2422c19:dd:d9:dd:c25:c25:d915:70f1/1282c19:dd:d9:dd:c25:c25:d915:70f1
2432c19:dd:d9:dd:c25:c25:d915:70f2/1282c19:dd:d9:dd:c25:c25:d915:70f2
2442c19:dd:d9:dd:c25:c25:d915:70f3/1282c19:dd:d9:dd:c25:c25:d915:70f3
2452c19:dd:d9:dd:c25:c25:d915:70f4/1282c19:dd:d9:dd:c25:c25:d915:70f4
2462c19:dd:d9:dd:c25:c25:d915:70f5/1282c19:dd:d9:dd:c25:c25:d915:70f5
2472c19:dd:d9:dd:c25:c25:d915:70f6/1282c19:dd:d9:dd:c25:c25:d915:70f6
2482c19:dd:d9:dd:c25:c25:d915:70f7/1282c19:dd:d9:dd:c25:c25:d915:70f7
2492c19:dd:d9:dd:c25:c25:d915:70f8/1282c19:dd:d9:dd:c25:c25:d915:70f8
2502c19:dd:d9:dd:c25:c25:d915:70f9/1282c19:dd:d9:dd:c25:c25:d915:70f9
2512c19:dd:d9:dd:c25:c25:d915:70fa/1282c19:dd:d9:dd:c25:c25:d915:70fa
2522c19:dd:d9:dd:c25:c25:d915:70fb/1282c19:dd:d9:dd:c25:c25:d915:70fb
2532c19:dd:d9:dd:c25:c25:d915:70fc/1282c19:dd:d9:dd:c25:c25:d915:70fc
2542c19:dd:d9:dd:c25:c25:d915:70fd/1282c19:dd:d9:dd:c25:c25:d915:70fd
2552c19:dd:d9:dd:c25:c25:d915:70fe/1282c19:dd:d9:dd:c25:c25:d915:70fe
2562c19:dd:d9:dd:c25:c25:d915:70ff/1282c19:dd:d9:dd:c25:c25:d915:70ff

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.