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:ec00:c25:c25e:dd:dddc:5000/116
First address
2c19:dd:ec00:c25:c25e:dd:dddc:5000
Last address
2c19:dd:ec00:c25:c25e:dd:dddc:5fff
Addresses
4,096
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:ec00:0c25:c25e:00dd:dddc:5000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
5.c.d.d.d.d.d.0.0.e.5.2.c.5.2.c.0.0.0.c.e.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:ec00:c25:c25e:dd:dddc:5000/116 makes 4,096 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:dddc:5000/1282c19:dd:ec00:c25:c25e:dd:dddc:5000
22c19:dd:ec00:c25:c25e:dd:dddc:5001/1282c19:dd:ec00:c25:c25e:dd:dddc:5001
32c19:dd:ec00:c25:c25e:dd:dddc:5002/1282c19:dd:ec00:c25:c25e:dd:dddc:5002
42c19:dd:ec00:c25:c25e:dd:dddc:5003/1282c19:dd:ec00:c25:c25e:dd:dddc:5003
52c19:dd:ec00:c25:c25e:dd:dddc:5004/1282c19:dd:ec00:c25:c25e:dd:dddc:5004
62c19:dd:ec00:c25:c25e:dd:dddc:5005/1282c19:dd:ec00:c25:c25e:dd:dddc:5005
72c19:dd:ec00:c25:c25e:dd:dddc:5006/1282c19:dd:ec00:c25:c25e:dd:dddc:5006
82c19:dd:ec00:c25:c25e:dd:dddc:5007/1282c19:dd:ec00:c25:c25e:dd:dddc:5007
92c19:dd:ec00:c25:c25e:dd:dddc:5008/1282c19:dd:ec00:c25:c25e:dd:dddc:5008
102c19:dd:ec00:c25:c25e:dd:dddc:5009/1282c19:dd:ec00:c25:c25e:dd:dddc:5009
112c19:dd:ec00:c25:c25e:dd:dddc:500a/1282c19:dd:ec00:c25:c25e:dd:dddc:500a
122c19:dd:ec00:c25:c25e:dd:dddc:500b/1282c19:dd:ec00:c25:c25e:dd:dddc:500b
132c19:dd:ec00:c25:c25e:dd:dddc:500c/1282c19:dd:ec00:c25:c25e:dd:dddc:500c
142c19:dd:ec00:c25:c25e:dd:dddc:500d/1282c19:dd:ec00:c25:c25e:dd:dddc:500d
152c19:dd:ec00:c25:c25e:dd:dddc:500e/1282c19:dd:ec00:c25:c25e:dd:dddc:500e
162c19:dd:ec00:c25:c25e:dd:dddc:500f/1282c19:dd:ec00:c25:c25e:dd:dddc:500f
172c19:dd:ec00:c25:c25e:dd:dddc:5010/1282c19:dd:ec00:c25:c25e:dd:dddc:5010
182c19:dd:ec00:c25:c25e:dd:dddc:5011/1282c19:dd:ec00:c25:c25e:dd:dddc:5011
192c19:dd:ec00:c25:c25e:dd:dddc:5012/1282c19:dd:ec00:c25:c25e:dd:dddc:5012
202c19:dd:ec00:c25:c25e:dd:dddc:5013/1282c19:dd:ec00:c25:c25e:dd:dddc:5013
212c19:dd:ec00:c25:c25e:dd:dddc:5014/1282c19:dd:ec00:c25:c25e:dd:dddc:5014
222c19:dd:ec00:c25:c25e:dd:dddc:5015/1282c19:dd:ec00:c25:c25e:dd:dddc:5015
232c19:dd:ec00:c25:c25e:dd:dddc:5016/1282c19:dd:ec00:c25:c25e:dd:dddc:5016
242c19:dd:ec00:c25:c25e:dd:dddc:5017/1282c19:dd:ec00:c25:c25e:dd:dddc:5017
252c19:dd:ec00:c25:c25e:dd:dddc:5018/1282c19:dd:ec00:c25:c25e:dd:dddc:5018
262c19:dd:ec00:c25:c25e:dd:dddc:5019/1282c19:dd:ec00:c25:c25e:dd:dddc:5019
272c19:dd:ec00:c25:c25e:dd:dddc:501a/1282c19:dd:ec00:c25:c25e:dd:dddc:501a
282c19:dd:ec00:c25:c25e:dd:dddc:501b/1282c19:dd:ec00:c25:c25e:dd:dddc:501b
292c19:dd:ec00:c25:c25e:dd:dddc:501c/1282c19:dd:ec00:c25:c25e:dd:dddc:501c
302c19:dd:ec00:c25:c25e:dd:dddc:501d/1282c19:dd:ec00:c25:c25e:dd:dddc:501d
312c19:dd:ec00:c25:c25e:dd:dddc:501e/1282c19:dd:ec00:c25:c25e:dd:dddc:501e
322c19:dd:ec00:c25:c25e:dd:dddc:501f/1282c19:dd:ec00:c25:c25e:dd:dddc:501f
332c19:dd:ec00:c25:c25e:dd:dddc:5020/1282c19:dd:ec00:c25:c25e:dd:dddc:5020
342c19:dd:ec00:c25:c25e:dd:dddc:5021/1282c19:dd:ec00:c25:c25e:dd:dddc:5021
352c19:dd:ec00:c25:c25e:dd:dddc:5022/1282c19:dd:ec00:c25:c25e:dd:dddc:5022
362c19:dd:ec00:c25:c25e:dd:dddc:5023/1282c19:dd:ec00:c25:c25e:dd:dddc:5023
372c19:dd:ec00:c25:c25e:dd:dddc:5024/1282c19:dd:ec00:c25:c25e:dd:dddc:5024
382c19:dd:ec00:c25:c25e:dd:dddc:5025/1282c19:dd:ec00:c25:c25e:dd:dddc:5025
392c19:dd:ec00:c25:c25e:dd:dddc:5026/1282c19:dd:ec00:c25:c25e:dd:dddc:5026
402c19:dd:ec00:c25:c25e:dd:dddc:5027/1282c19:dd:ec00:c25:c25e:dd:dddc:5027
412c19:dd:ec00:c25:c25e:dd:dddc:5028/1282c19:dd:ec00:c25:c25e:dd:dddc:5028
422c19:dd:ec00:c25:c25e:dd:dddc:5029/1282c19:dd:ec00:c25:c25e:dd:dddc:5029
432c19:dd:ec00:c25:c25e:dd:dddc:502a/1282c19:dd:ec00:c25:c25e:dd:dddc:502a
442c19:dd:ec00:c25:c25e:dd:dddc:502b/1282c19:dd:ec00:c25:c25e:dd:dddc:502b
452c19:dd:ec00:c25:c25e:dd:dddc:502c/1282c19:dd:ec00:c25:c25e:dd:dddc:502c
462c19:dd:ec00:c25:c25e:dd:dddc:502d/1282c19:dd:ec00:c25:c25e:dd:dddc:502d
472c19:dd:ec00:c25:c25e:dd:dddc:502e/1282c19:dd:ec00:c25:c25e:dd:dddc:502e
482c19:dd:ec00:c25:c25e:dd:dddc:502f/1282c19:dd:ec00:c25:c25e:dd:dddc:502f
492c19:dd:ec00:c25:c25e:dd:dddc:5030/1282c19:dd:ec00:c25:c25e:dd:dddc:5030
502c19:dd:ec00:c25:c25e:dd:dddc:5031/1282c19:dd:ec00:c25:c25e:dd:dddc:5031
512c19:dd:ec00:c25:c25e:dd:dddc:5032/1282c19:dd:ec00:c25:c25e:dd:dddc:5032
522c19:dd:ec00:c25:c25e:dd:dddc:5033/1282c19:dd:ec00:c25:c25e:dd:dddc:5033
532c19:dd:ec00:c25:c25e:dd:dddc:5034/1282c19:dd:ec00:c25:c25e:dd:dddc:5034
542c19:dd:ec00:c25:c25e:dd:dddc:5035/1282c19:dd:ec00:c25:c25e:dd:dddc:5035
552c19:dd:ec00:c25:c25e:dd:dddc:5036/1282c19:dd:ec00:c25:c25e:dd:dddc:5036
562c19:dd:ec00:c25:c25e:dd:dddc:5037/1282c19:dd:ec00:c25:c25e:dd:dddc:5037
572c19:dd:ec00:c25:c25e:dd:dddc:5038/1282c19:dd:ec00:c25:c25e:dd:dddc:5038
582c19:dd:ec00:c25:c25e:dd:dddc:5039/1282c19:dd:ec00:c25:c25e:dd:dddc:5039
592c19:dd:ec00:c25:c25e:dd:dddc:503a/1282c19:dd:ec00:c25:c25e:dd:dddc:503a
602c19:dd:ec00:c25:c25e:dd:dddc:503b/1282c19:dd:ec00:c25:c25e:dd:dddc:503b
612c19:dd:ec00:c25:c25e:dd:dddc:503c/1282c19:dd:ec00:c25:c25e:dd:dddc:503c
622c19:dd:ec00:c25:c25e:dd:dddc:503d/1282c19:dd:ec00:c25:c25e:dd:dddc:503d
632c19:dd:ec00:c25:c25e:dd:dddc:503e/1282c19:dd:ec00:c25:c25e:dd:dddc:503e
642c19:dd:ec00:c25:c25e:dd:dddc:503f/1282c19:dd:ec00:c25:c25e:dd:dddc:503f
652c19:dd:ec00:c25:c25e:dd:dddc:5040/1282c19:dd:ec00:c25:c25e:dd:dddc:5040
662c19:dd:ec00:c25:c25e:dd:dddc:5041/1282c19:dd:ec00:c25:c25e:dd:dddc:5041
672c19:dd:ec00:c25:c25e:dd:dddc:5042/1282c19:dd:ec00:c25:c25e:dd:dddc:5042
682c19:dd:ec00:c25:c25e:dd:dddc:5043/1282c19:dd:ec00:c25:c25e:dd:dddc:5043
692c19:dd:ec00:c25:c25e:dd:dddc:5044/1282c19:dd:ec00:c25:c25e:dd:dddc:5044
702c19:dd:ec00:c25:c25e:dd:dddc:5045/1282c19:dd:ec00:c25:c25e:dd:dddc:5045
712c19:dd:ec00:c25:c25e:dd:dddc:5046/1282c19:dd:ec00:c25:c25e:dd:dddc:5046
722c19:dd:ec00:c25:c25e:dd:dddc:5047/1282c19:dd:ec00:c25:c25e:dd:dddc:5047
732c19:dd:ec00:c25:c25e:dd:dddc:5048/1282c19:dd:ec00:c25:c25e:dd:dddc:5048
742c19:dd:ec00:c25:c25e:dd:dddc:5049/1282c19:dd:ec00:c25:c25e:dd:dddc:5049
752c19:dd:ec00:c25:c25e:dd:dddc:504a/1282c19:dd:ec00:c25:c25e:dd:dddc:504a
762c19:dd:ec00:c25:c25e:dd:dddc:504b/1282c19:dd:ec00:c25:c25e:dd:dddc:504b
772c19:dd:ec00:c25:c25e:dd:dddc:504c/1282c19:dd:ec00:c25:c25e:dd:dddc:504c
782c19:dd:ec00:c25:c25e:dd:dddc:504d/1282c19:dd:ec00:c25:c25e:dd:dddc:504d
792c19:dd:ec00:c25:c25e:dd:dddc:504e/1282c19:dd:ec00:c25:c25e:dd:dddc:504e
802c19:dd:ec00:c25:c25e:dd:dddc:504f/1282c19:dd:ec00:c25:c25e:dd:dddc:504f
812c19:dd:ec00:c25:c25e:dd:dddc:5050/1282c19:dd:ec00:c25:c25e:dd:dddc:5050
822c19:dd:ec00:c25:c25e:dd:dddc:5051/1282c19:dd:ec00:c25:c25e:dd:dddc:5051
832c19:dd:ec00:c25:c25e:dd:dddc:5052/1282c19:dd:ec00:c25:c25e:dd:dddc:5052
842c19:dd:ec00:c25:c25e:dd:dddc:5053/1282c19:dd:ec00:c25:c25e:dd:dddc:5053
852c19:dd:ec00:c25:c25e:dd:dddc:5054/1282c19:dd:ec00:c25:c25e:dd:dddc:5054
862c19:dd:ec00:c25:c25e:dd:dddc:5055/1282c19:dd:ec00:c25:c25e:dd:dddc:5055
872c19:dd:ec00:c25:c25e:dd:dddc:5056/1282c19:dd:ec00:c25:c25e:dd:dddc:5056
882c19:dd:ec00:c25:c25e:dd:dddc:5057/1282c19:dd:ec00:c25:c25e:dd:dddc:5057
892c19:dd:ec00:c25:c25e:dd:dddc:5058/1282c19:dd:ec00:c25:c25e:dd:dddc:5058
902c19:dd:ec00:c25:c25e:dd:dddc:5059/1282c19:dd:ec00:c25:c25e:dd:dddc:5059
912c19:dd:ec00:c25:c25e:dd:dddc:505a/1282c19:dd:ec00:c25:c25e:dd:dddc:505a
922c19:dd:ec00:c25:c25e:dd:dddc:505b/1282c19:dd:ec00:c25:c25e:dd:dddc:505b
932c19:dd:ec00:c25:c25e:dd:dddc:505c/1282c19:dd:ec00:c25:c25e:dd:dddc:505c
942c19:dd:ec00:c25:c25e:dd:dddc:505d/1282c19:dd:ec00:c25:c25e:dd:dddc:505d
952c19:dd:ec00:c25:c25e:dd:dddc:505e/1282c19:dd:ec00:c25:c25e:dd:dddc:505e
962c19:dd:ec00:c25:c25e:dd:dddc:505f/1282c19:dd:ec00:c25:c25e:dd:dddc:505f
972c19:dd:ec00:c25:c25e:dd:dddc:5060/1282c19:dd:ec00:c25:c25e:dd:dddc:5060
982c19:dd:ec00:c25:c25e:dd:dddc:5061/1282c19:dd:ec00:c25:c25e:dd:dddc:5061
992c19:dd:ec00:c25:c25e:dd:dddc:5062/1282c19:dd:ec00:c25:c25e:dd:dddc:5062
1002c19:dd:ec00:c25:c25e:dd:dddc:5063/1282c19:dd:ec00:c25:c25e:dd:dddc:5063
1012c19:dd:ec00:c25:c25e:dd:dddc:5064/1282c19:dd:ec00:c25:c25e:dd:dddc:5064
1022c19:dd:ec00:c25:c25e:dd:dddc:5065/1282c19:dd:ec00:c25:c25e:dd:dddc:5065
1032c19:dd:ec00:c25:c25e:dd:dddc:5066/1282c19:dd:ec00:c25:c25e:dd:dddc:5066
1042c19:dd:ec00:c25:c25e:dd:dddc:5067/1282c19:dd:ec00:c25:c25e:dd:dddc:5067
1052c19:dd:ec00:c25:c25e:dd:dddc:5068/1282c19:dd:ec00:c25:c25e:dd:dddc:5068
1062c19:dd:ec00:c25:c25e:dd:dddc:5069/1282c19:dd:ec00:c25:c25e:dd:dddc:5069
1072c19:dd:ec00:c25:c25e:dd:dddc:506a/1282c19:dd:ec00:c25:c25e:dd:dddc:506a
1082c19:dd:ec00:c25:c25e:dd:dddc:506b/1282c19:dd:ec00:c25:c25e:dd:dddc:506b
1092c19:dd:ec00:c25:c25e:dd:dddc:506c/1282c19:dd:ec00:c25:c25e:dd:dddc:506c
1102c19:dd:ec00:c25:c25e:dd:dddc:506d/1282c19:dd:ec00:c25:c25e:dd:dddc:506d
1112c19:dd:ec00:c25:c25e:dd:dddc:506e/1282c19:dd:ec00:c25:c25e:dd:dddc:506e
1122c19:dd:ec00:c25:c25e:dd:dddc:506f/1282c19:dd:ec00:c25:c25e:dd:dddc:506f
1132c19:dd:ec00:c25:c25e:dd:dddc:5070/1282c19:dd:ec00:c25:c25e:dd:dddc:5070
1142c19:dd:ec00:c25:c25e:dd:dddc:5071/1282c19:dd:ec00:c25:c25e:dd:dddc:5071
1152c19:dd:ec00:c25:c25e:dd:dddc:5072/1282c19:dd:ec00:c25:c25e:dd:dddc:5072
1162c19:dd:ec00:c25:c25e:dd:dddc:5073/1282c19:dd:ec00:c25:c25e:dd:dddc:5073
1172c19:dd:ec00:c25:c25e:dd:dddc:5074/1282c19:dd:ec00:c25:c25e:dd:dddc:5074
1182c19:dd:ec00:c25:c25e:dd:dddc:5075/1282c19:dd:ec00:c25:c25e:dd:dddc:5075
1192c19:dd:ec00:c25:c25e:dd:dddc:5076/1282c19:dd:ec00:c25:c25e:dd:dddc:5076
1202c19:dd:ec00:c25:c25e:dd:dddc:5077/1282c19:dd:ec00:c25:c25e:dd:dddc:5077
1212c19:dd:ec00:c25:c25e:dd:dddc:5078/1282c19:dd:ec00:c25:c25e:dd:dddc:5078
1222c19:dd:ec00:c25:c25e:dd:dddc:5079/1282c19:dd:ec00:c25:c25e:dd:dddc:5079
1232c19:dd:ec00:c25:c25e:dd:dddc:507a/1282c19:dd:ec00:c25:c25e:dd:dddc:507a
1242c19:dd:ec00:c25:c25e:dd:dddc:507b/1282c19:dd:ec00:c25:c25e:dd:dddc:507b
1252c19:dd:ec00:c25:c25e:dd:dddc:507c/1282c19:dd:ec00:c25:c25e:dd:dddc:507c
1262c19:dd:ec00:c25:c25e:dd:dddc:507d/1282c19:dd:ec00:c25:c25e:dd:dddc:507d
1272c19:dd:ec00:c25:c25e:dd:dddc:507e/1282c19:dd:ec00:c25:c25e:dd:dddc:507e
1282c19:dd:ec00:c25:c25e:dd:dddc:507f/1282c19:dd:ec00:c25:c25e:dd:dddc:507f
1292c19:dd:ec00:c25:c25e:dd:dddc:5080/1282c19:dd:ec00:c25:c25e:dd:dddc:5080
1302c19:dd:ec00:c25:c25e:dd:dddc:5081/1282c19:dd:ec00:c25:c25e:dd:dddc:5081
1312c19:dd:ec00:c25:c25e:dd:dddc:5082/1282c19:dd:ec00:c25:c25e:dd:dddc:5082
1322c19:dd:ec00:c25:c25e:dd:dddc:5083/1282c19:dd:ec00:c25:c25e:dd:dddc:5083
1332c19:dd:ec00:c25:c25e:dd:dddc:5084/1282c19:dd:ec00:c25:c25e:dd:dddc:5084
1342c19:dd:ec00:c25:c25e:dd:dddc:5085/1282c19:dd:ec00:c25:c25e:dd:dddc:5085
1352c19:dd:ec00:c25:c25e:dd:dddc:5086/1282c19:dd:ec00:c25:c25e:dd:dddc:5086
1362c19:dd:ec00:c25:c25e:dd:dddc:5087/1282c19:dd:ec00:c25:c25e:dd:dddc:5087
1372c19:dd:ec00:c25:c25e:dd:dddc:5088/1282c19:dd:ec00:c25:c25e:dd:dddc:5088
1382c19:dd:ec00:c25:c25e:dd:dddc:5089/1282c19:dd:ec00:c25:c25e:dd:dddc:5089
1392c19:dd:ec00:c25:c25e:dd:dddc:508a/1282c19:dd:ec00:c25:c25e:dd:dddc:508a
1402c19:dd:ec00:c25:c25e:dd:dddc:508b/1282c19:dd:ec00:c25:c25e:dd:dddc:508b
1412c19:dd:ec00:c25:c25e:dd:dddc:508c/1282c19:dd:ec00:c25:c25e:dd:dddc:508c
1422c19:dd:ec00:c25:c25e:dd:dddc:508d/1282c19:dd:ec00:c25:c25e:dd:dddc:508d
1432c19:dd:ec00:c25:c25e:dd:dddc:508e/1282c19:dd:ec00:c25:c25e:dd:dddc:508e
1442c19:dd:ec00:c25:c25e:dd:dddc:508f/1282c19:dd:ec00:c25:c25e:dd:dddc:508f
1452c19:dd:ec00:c25:c25e:dd:dddc:5090/1282c19:dd:ec00:c25:c25e:dd:dddc:5090
1462c19:dd:ec00:c25:c25e:dd:dddc:5091/1282c19:dd:ec00:c25:c25e:dd:dddc:5091
1472c19:dd:ec00:c25:c25e:dd:dddc:5092/1282c19:dd:ec00:c25:c25e:dd:dddc:5092
1482c19:dd:ec00:c25:c25e:dd:dddc:5093/1282c19:dd:ec00:c25:c25e:dd:dddc:5093
1492c19:dd:ec00:c25:c25e:dd:dddc:5094/1282c19:dd:ec00:c25:c25e:dd:dddc:5094
1502c19:dd:ec00:c25:c25e:dd:dddc:5095/1282c19:dd:ec00:c25:c25e:dd:dddc:5095
1512c19:dd:ec00:c25:c25e:dd:dddc:5096/1282c19:dd:ec00:c25:c25e:dd:dddc:5096
1522c19:dd:ec00:c25:c25e:dd:dddc:5097/1282c19:dd:ec00:c25:c25e:dd:dddc:5097
1532c19:dd:ec00:c25:c25e:dd:dddc:5098/1282c19:dd:ec00:c25:c25e:dd:dddc:5098
1542c19:dd:ec00:c25:c25e:dd:dddc:5099/1282c19:dd:ec00:c25:c25e:dd:dddc:5099
1552c19:dd:ec00:c25:c25e:dd:dddc:509a/1282c19:dd:ec00:c25:c25e:dd:dddc:509a
1562c19:dd:ec00:c25:c25e:dd:dddc:509b/1282c19:dd:ec00:c25:c25e:dd:dddc:509b
1572c19:dd:ec00:c25:c25e:dd:dddc:509c/1282c19:dd:ec00:c25:c25e:dd:dddc:509c
1582c19:dd:ec00:c25:c25e:dd:dddc:509d/1282c19:dd:ec00:c25:c25e:dd:dddc:509d
1592c19:dd:ec00:c25:c25e:dd:dddc:509e/1282c19:dd:ec00:c25:c25e:dd:dddc:509e
1602c19:dd:ec00:c25:c25e:dd:dddc:509f/1282c19:dd:ec00:c25:c25e:dd:dddc:509f
1612c19:dd:ec00:c25:c25e:dd:dddc:50a0/1282c19:dd:ec00:c25:c25e:dd:dddc:50a0
1622c19:dd:ec00:c25:c25e:dd:dddc:50a1/1282c19:dd:ec00:c25:c25e:dd:dddc:50a1
1632c19:dd:ec00:c25:c25e:dd:dddc:50a2/1282c19:dd:ec00:c25:c25e:dd:dddc:50a2
1642c19:dd:ec00:c25:c25e:dd:dddc:50a3/1282c19:dd:ec00:c25:c25e:dd:dddc:50a3
1652c19:dd:ec00:c25:c25e:dd:dddc:50a4/1282c19:dd:ec00:c25:c25e:dd:dddc:50a4
1662c19:dd:ec00:c25:c25e:dd:dddc:50a5/1282c19:dd:ec00:c25:c25e:dd:dddc:50a5
1672c19:dd:ec00:c25:c25e:dd:dddc:50a6/1282c19:dd:ec00:c25:c25e:dd:dddc:50a6
1682c19:dd:ec00:c25:c25e:dd:dddc:50a7/1282c19:dd:ec00:c25:c25e:dd:dddc:50a7
1692c19:dd:ec00:c25:c25e:dd:dddc:50a8/1282c19:dd:ec00:c25:c25e:dd:dddc:50a8
1702c19:dd:ec00:c25:c25e:dd:dddc:50a9/1282c19:dd:ec00:c25:c25e:dd:dddc:50a9
1712c19:dd:ec00:c25:c25e:dd:dddc:50aa/1282c19:dd:ec00:c25:c25e:dd:dddc:50aa
1722c19:dd:ec00:c25:c25e:dd:dddc:50ab/1282c19:dd:ec00:c25:c25e:dd:dddc:50ab
1732c19:dd:ec00:c25:c25e:dd:dddc:50ac/1282c19:dd:ec00:c25:c25e:dd:dddc:50ac
1742c19:dd:ec00:c25:c25e:dd:dddc:50ad/1282c19:dd:ec00:c25:c25e:dd:dddc:50ad
1752c19:dd:ec00:c25:c25e:dd:dddc:50ae/1282c19:dd:ec00:c25:c25e:dd:dddc:50ae
1762c19:dd:ec00:c25:c25e:dd:dddc:50af/1282c19:dd:ec00:c25:c25e:dd:dddc:50af
1772c19:dd:ec00:c25:c25e:dd:dddc:50b0/1282c19:dd:ec00:c25:c25e:dd:dddc:50b0
1782c19:dd:ec00:c25:c25e:dd:dddc:50b1/1282c19:dd:ec00:c25:c25e:dd:dddc:50b1
1792c19:dd:ec00:c25:c25e:dd:dddc:50b2/1282c19:dd:ec00:c25:c25e:dd:dddc:50b2
1802c19:dd:ec00:c25:c25e:dd:dddc:50b3/1282c19:dd:ec00:c25:c25e:dd:dddc:50b3
1812c19:dd:ec00:c25:c25e:dd:dddc:50b4/1282c19:dd:ec00:c25:c25e:dd:dddc:50b4
1822c19:dd:ec00:c25:c25e:dd:dddc:50b5/1282c19:dd:ec00:c25:c25e:dd:dddc:50b5
1832c19:dd:ec00:c25:c25e:dd:dddc:50b6/1282c19:dd:ec00:c25:c25e:dd:dddc:50b6
1842c19:dd:ec00:c25:c25e:dd:dddc:50b7/1282c19:dd:ec00:c25:c25e:dd:dddc:50b7
1852c19:dd:ec00:c25:c25e:dd:dddc:50b8/1282c19:dd:ec00:c25:c25e:dd:dddc:50b8
1862c19:dd:ec00:c25:c25e:dd:dddc:50b9/1282c19:dd:ec00:c25:c25e:dd:dddc:50b9
1872c19:dd:ec00:c25:c25e:dd:dddc:50ba/1282c19:dd:ec00:c25:c25e:dd:dddc:50ba
1882c19:dd:ec00:c25:c25e:dd:dddc:50bb/1282c19:dd:ec00:c25:c25e:dd:dddc:50bb
1892c19:dd:ec00:c25:c25e:dd:dddc:50bc/1282c19:dd:ec00:c25:c25e:dd:dddc:50bc
1902c19:dd:ec00:c25:c25e:dd:dddc:50bd/1282c19:dd:ec00:c25:c25e:dd:dddc:50bd
1912c19:dd:ec00:c25:c25e:dd:dddc:50be/1282c19:dd:ec00:c25:c25e:dd:dddc:50be
1922c19:dd:ec00:c25:c25e:dd:dddc:50bf/1282c19:dd:ec00:c25:c25e:dd:dddc:50bf
1932c19:dd:ec00:c25:c25e:dd:dddc:50c0/1282c19:dd:ec00:c25:c25e:dd:dddc:50c0
1942c19:dd:ec00:c25:c25e:dd:dddc:50c1/1282c19:dd:ec00:c25:c25e:dd:dddc:50c1
1952c19:dd:ec00:c25:c25e:dd:dddc:50c2/1282c19:dd:ec00:c25:c25e:dd:dddc:50c2
1962c19:dd:ec00:c25:c25e:dd:dddc:50c3/1282c19:dd:ec00:c25:c25e:dd:dddc:50c3
1972c19:dd:ec00:c25:c25e:dd:dddc:50c4/1282c19:dd:ec00:c25:c25e:dd:dddc:50c4
1982c19:dd:ec00:c25:c25e:dd:dddc:50c5/1282c19:dd:ec00:c25:c25e:dd:dddc:50c5
1992c19:dd:ec00:c25:c25e:dd:dddc:50c6/1282c19:dd:ec00:c25:c25e:dd:dddc:50c6
2002c19:dd:ec00:c25:c25e:dd:dddc:50c7/1282c19:dd:ec00:c25:c25e:dd:dddc:50c7
2012c19:dd:ec00:c25:c25e:dd:dddc:50c8/1282c19:dd:ec00:c25:c25e:dd:dddc:50c8
2022c19:dd:ec00:c25:c25e:dd:dddc:50c9/1282c19:dd:ec00:c25:c25e:dd:dddc:50c9
2032c19:dd:ec00:c25:c25e:dd:dddc:50ca/1282c19:dd:ec00:c25:c25e:dd:dddc:50ca
2042c19:dd:ec00:c25:c25e:dd:dddc:50cb/1282c19:dd:ec00:c25:c25e:dd:dddc:50cb
2052c19:dd:ec00:c25:c25e:dd:dddc:50cc/1282c19:dd:ec00:c25:c25e:dd:dddc:50cc
2062c19:dd:ec00:c25:c25e:dd:dddc:50cd/1282c19:dd:ec00:c25:c25e:dd:dddc:50cd
2072c19:dd:ec00:c25:c25e:dd:dddc:50ce/1282c19:dd:ec00:c25:c25e:dd:dddc:50ce
2082c19:dd:ec00:c25:c25e:dd:dddc:50cf/1282c19:dd:ec00:c25:c25e:dd:dddc:50cf
2092c19:dd:ec00:c25:c25e:dd:dddc:50d0/1282c19:dd:ec00:c25:c25e:dd:dddc:50d0
2102c19:dd:ec00:c25:c25e:dd:dddc:50d1/1282c19:dd:ec00:c25:c25e:dd:dddc:50d1
2112c19:dd:ec00:c25:c25e:dd:dddc:50d2/1282c19:dd:ec00:c25:c25e:dd:dddc:50d2
2122c19:dd:ec00:c25:c25e:dd:dddc:50d3/1282c19:dd:ec00:c25:c25e:dd:dddc:50d3
2132c19:dd:ec00:c25:c25e:dd:dddc:50d4/1282c19:dd:ec00:c25:c25e:dd:dddc:50d4
2142c19:dd:ec00:c25:c25e:dd:dddc:50d5/1282c19:dd:ec00:c25:c25e:dd:dddc:50d5
2152c19:dd:ec00:c25:c25e:dd:dddc:50d6/1282c19:dd:ec00:c25:c25e:dd:dddc:50d6
2162c19:dd:ec00:c25:c25e:dd:dddc:50d7/1282c19:dd:ec00:c25:c25e:dd:dddc:50d7
2172c19:dd:ec00:c25:c25e:dd:dddc:50d8/1282c19:dd:ec00:c25:c25e:dd:dddc:50d8
2182c19:dd:ec00:c25:c25e:dd:dddc:50d9/1282c19:dd:ec00:c25:c25e:dd:dddc:50d9
2192c19:dd:ec00:c25:c25e:dd:dddc:50da/1282c19:dd:ec00:c25:c25e:dd:dddc:50da
2202c19:dd:ec00:c25:c25e:dd:dddc:50db/1282c19:dd:ec00:c25:c25e:dd:dddc:50db
2212c19:dd:ec00:c25:c25e:dd:dddc:50dc/1282c19:dd:ec00:c25:c25e:dd:dddc:50dc
2222c19:dd:ec00:c25:c25e:dd:dddc:50dd/1282c19:dd:ec00:c25:c25e:dd:dddc:50dd
2232c19:dd:ec00:c25:c25e:dd:dddc:50de/1282c19:dd:ec00:c25:c25e:dd:dddc:50de
2242c19:dd:ec00:c25:c25e:dd:dddc:50df/1282c19:dd:ec00:c25:c25e:dd:dddc:50df
2252c19:dd:ec00:c25:c25e:dd:dddc:50e0/1282c19:dd:ec00:c25:c25e:dd:dddc:50e0
2262c19:dd:ec00:c25:c25e:dd:dddc:50e1/1282c19:dd:ec00:c25:c25e:dd:dddc:50e1
2272c19:dd:ec00:c25:c25e:dd:dddc:50e2/1282c19:dd:ec00:c25:c25e:dd:dddc:50e2
2282c19:dd:ec00:c25:c25e:dd:dddc:50e3/1282c19:dd:ec00:c25:c25e:dd:dddc:50e3
2292c19:dd:ec00:c25:c25e:dd:dddc:50e4/1282c19:dd:ec00:c25:c25e:dd:dddc:50e4
2302c19:dd:ec00:c25:c25e:dd:dddc:50e5/1282c19:dd:ec00:c25:c25e:dd:dddc:50e5
2312c19:dd:ec00:c25:c25e:dd:dddc:50e6/1282c19:dd:ec00:c25:c25e:dd:dddc:50e6
2322c19:dd:ec00:c25:c25e:dd:dddc:50e7/1282c19:dd:ec00:c25:c25e:dd:dddc:50e7
2332c19:dd:ec00:c25:c25e:dd:dddc:50e8/1282c19:dd:ec00:c25:c25e:dd:dddc:50e8
2342c19:dd:ec00:c25:c25e:dd:dddc:50e9/1282c19:dd:ec00:c25:c25e:dd:dddc:50e9
2352c19:dd:ec00:c25:c25e:dd:dddc:50ea/1282c19:dd:ec00:c25:c25e:dd:dddc:50ea
2362c19:dd:ec00:c25:c25e:dd:dddc:50eb/1282c19:dd:ec00:c25:c25e:dd:dddc:50eb
2372c19:dd:ec00:c25:c25e:dd:dddc:50ec/1282c19:dd:ec00:c25:c25e:dd:dddc:50ec
2382c19:dd:ec00:c25:c25e:dd:dddc:50ed/1282c19:dd:ec00:c25:c25e:dd:dddc:50ed
2392c19:dd:ec00:c25:c25e:dd:dddc:50ee/1282c19:dd:ec00:c25:c25e:dd:dddc:50ee
2402c19:dd:ec00:c25:c25e:dd:dddc:50ef/1282c19:dd:ec00:c25:c25e:dd:dddc:50ef
2412c19:dd:ec00:c25:c25e:dd:dddc:50f0/1282c19:dd:ec00:c25:c25e:dd:dddc:50f0
2422c19:dd:ec00:c25:c25e:dd:dddc:50f1/1282c19:dd:ec00:c25:c25e:dd:dddc:50f1
2432c19:dd:ec00:c25:c25e:dd:dddc:50f2/1282c19:dd:ec00:c25:c25e:dd:dddc:50f2
2442c19:dd:ec00:c25:c25e:dd:dddc:50f3/1282c19:dd:ec00:c25:c25e:dd:dddc:50f3
2452c19:dd:ec00:c25:c25e:dd:dddc:50f4/1282c19:dd:ec00:c25:c25e:dd:dddc:50f4
2462c19:dd:ec00:c25:c25e:dd:dddc:50f5/1282c19:dd:ec00:c25:c25e:dd:dddc:50f5
2472c19:dd:ec00:c25:c25e:dd:dddc:50f6/1282c19:dd:ec00:c25:c25e:dd:dddc:50f6
2482c19:dd:ec00:c25:c25e:dd:dddc:50f7/1282c19:dd:ec00:c25:c25e:dd:dddc:50f7
2492c19:dd:ec00:c25:c25e:dd:dddc:50f8/1282c19:dd:ec00:c25:c25e:dd:dddc:50f8
2502c19:dd:ec00:c25:c25e:dd:dddc:50f9/1282c19:dd:ec00:c25:c25e:dd:dddc:50f9
2512c19:dd:ec00:c25:c25e:dd:dddc:50fa/1282c19:dd:ec00:c25:c25e:dd:dddc:50fa
2522c19:dd:ec00:c25:c25e:dd:dddc:50fb/1282c19:dd:ec00:c25:c25e:dd:dddc:50fb
2532c19:dd:ec00:c25:c25e:dd:dddc:50fc/1282c19:dd:ec00:c25:c25e:dd:dddc:50fc
2542c19:dd:ec00:c25:c25e:dd:dddc:50fd/1282c19:dd:ec00:c25:c25e:dd:dddc:50fd
2552c19:dd:ec00:c25:c25e:dd:dddc:50fe/1282c19:dd:ec00:c25:c25e:dd:dddc:50fe
2562c19:dd:ec00:c25:c25e:dd:dddc:50ff/1282c19:dd:ec00:c25:c25e:dd:dddc:50ff

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.