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:dd18:6000/116
First address
2c19:dd:d9:dd:c25:c25:dd18:6000
Last address
2c19:dd:d9:dd:c25:c25:dd18:6fff
Addresses
4,096
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:dd18:6000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
6.8.1.d.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
/117 (2)/118 (4)/119 (8)/120 (16)/124 (256)/127 (2,048)/128 (4,096)

2c19:dd:d9:dd:c25:c25:dd18:6000/116 makes 4,096 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:dd18:6000/1282c19:dd:d9:dd:c25:c25:dd18:6000
22c19:dd:d9:dd:c25:c25:dd18:6001/1282c19:dd:d9:dd:c25:c25:dd18:6001
32c19:dd:d9:dd:c25:c25:dd18:6002/1282c19:dd:d9:dd:c25:c25:dd18:6002
42c19:dd:d9:dd:c25:c25:dd18:6003/1282c19:dd:d9:dd:c25:c25:dd18:6003
52c19:dd:d9:dd:c25:c25:dd18:6004/1282c19:dd:d9:dd:c25:c25:dd18:6004
62c19:dd:d9:dd:c25:c25:dd18:6005/1282c19:dd:d9:dd:c25:c25:dd18:6005
72c19:dd:d9:dd:c25:c25:dd18:6006/1282c19:dd:d9:dd:c25:c25:dd18:6006
82c19:dd:d9:dd:c25:c25:dd18:6007/1282c19:dd:d9:dd:c25:c25:dd18:6007
92c19:dd:d9:dd:c25:c25:dd18:6008/1282c19:dd:d9:dd:c25:c25:dd18:6008
102c19:dd:d9:dd:c25:c25:dd18:6009/1282c19:dd:d9:dd:c25:c25:dd18:6009
112c19:dd:d9:dd:c25:c25:dd18:600a/1282c19:dd:d9:dd:c25:c25:dd18:600a
122c19:dd:d9:dd:c25:c25:dd18:600b/1282c19:dd:d9:dd:c25:c25:dd18:600b
132c19:dd:d9:dd:c25:c25:dd18:600c/1282c19:dd:d9:dd:c25:c25:dd18:600c
142c19:dd:d9:dd:c25:c25:dd18:600d/1282c19:dd:d9:dd:c25:c25:dd18:600d
152c19:dd:d9:dd:c25:c25:dd18:600e/1282c19:dd:d9:dd:c25:c25:dd18:600e
162c19:dd:d9:dd:c25:c25:dd18:600f/1282c19:dd:d9:dd:c25:c25:dd18:600f
172c19:dd:d9:dd:c25:c25:dd18:6010/1282c19:dd:d9:dd:c25:c25:dd18:6010
182c19:dd:d9:dd:c25:c25:dd18:6011/1282c19:dd:d9:dd:c25:c25:dd18:6011
192c19:dd:d9:dd:c25:c25:dd18:6012/1282c19:dd:d9:dd:c25:c25:dd18:6012
202c19:dd:d9:dd:c25:c25:dd18:6013/1282c19:dd:d9:dd:c25:c25:dd18:6013
212c19:dd:d9:dd:c25:c25:dd18:6014/1282c19:dd:d9:dd:c25:c25:dd18:6014
222c19:dd:d9:dd:c25:c25:dd18:6015/1282c19:dd:d9:dd:c25:c25:dd18:6015
232c19:dd:d9:dd:c25:c25:dd18:6016/1282c19:dd:d9:dd:c25:c25:dd18:6016
242c19:dd:d9:dd:c25:c25:dd18:6017/1282c19:dd:d9:dd:c25:c25:dd18:6017
252c19:dd:d9:dd:c25:c25:dd18:6018/1282c19:dd:d9:dd:c25:c25:dd18:6018
262c19:dd:d9:dd:c25:c25:dd18:6019/1282c19:dd:d9:dd:c25:c25:dd18:6019
272c19:dd:d9:dd:c25:c25:dd18:601a/1282c19:dd:d9:dd:c25:c25:dd18:601a
282c19:dd:d9:dd:c25:c25:dd18:601b/1282c19:dd:d9:dd:c25:c25:dd18:601b
292c19:dd:d9:dd:c25:c25:dd18:601c/1282c19:dd:d9:dd:c25:c25:dd18:601c
302c19:dd:d9:dd:c25:c25:dd18:601d/1282c19:dd:d9:dd:c25:c25:dd18:601d
312c19:dd:d9:dd:c25:c25:dd18:601e/1282c19:dd:d9:dd:c25:c25:dd18:601e
322c19:dd:d9:dd:c25:c25:dd18:601f/1282c19:dd:d9:dd:c25:c25:dd18:601f
332c19:dd:d9:dd:c25:c25:dd18:6020/1282c19:dd:d9:dd:c25:c25:dd18:6020
342c19:dd:d9:dd:c25:c25:dd18:6021/1282c19:dd:d9:dd:c25:c25:dd18:6021
352c19:dd:d9:dd:c25:c25:dd18:6022/1282c19:dd:d9:dd:c25:c25:dd18:6022
362c19:dd:d9:dd:c25:c25:dd18:6023/1282c19:dd:d9:dd:c25:c25:dd18:6023
372c19:dd:d9:dd:c25:c25:dd18:6024/1282c19:dd:d9:dd:c25:c25:dd18:6024
382c19:dd:d9:dd:c25:c25:dd18:6025/1282c19:dd:d9:dd:c25:c25:dd18:6025
392c19:dd:d9:dd:c25:c25:dd18:6026/1282c19:dd:d9:dd:c25:c25:dd18:6026
402c19:dd:d9:dd:c25:c25:dd18:6027/1282c19:dd:d9:dd:c25:c25:dd18:6027
412c19:dd:d9:dd:c25:c25:dd18:6028/1282c19:dd:d9:dd:c25:c25:dd18:6028
422c19:dd:d9:dd:c25:c25:dd18:6029/1282c19:dd:d9:dd:c25:c25:dd18:6029
432c19:dd:d9:dd:c25:c25:dd18:602a/1282c19:dd:d9:dd:c25:c25:dd18:602a
442c19:dd:d9:dd:c25:c25:dd18:602b/1282c19:dd:d9:dd:c25:c25:dd18:602b
452c19:dd:d9:dd:c25:c25:dd18:602c/1282c19:dd:d9:dd:c25:c25:dd18:602c
462c19:dd:d9:dd:c25:c25:dd18:602d/1282c19:dd:d9:dd:c25:c25:dd18:602d
472c19:dd:d9:dd:c25:c25:dd18:602e/1282c19:dd:d9:dd:c25:c25:dd18:602e
482c19:dd:d9:dd:c25:c25:dd18:602f/1282c19:dd:d9:dd:c25:c25:dd18:602f
492c19:dd:d9:dd:c25:c25:dd18:6030/1282c19:dd:d9:dd:c25:c25:dd18:6030
502c19:dd:d9:dd:c25:c25:dd18:6031/1282c19:dd:d9:dd:c25:c25:dd18:6031
512c19:dd:d9:dd:c25:c25:dd18:6032/1282c19:dd:d9:dd:c25:c25:dd18:6032
522c19:dd:d9:dd:c25:c25:dd18:6033/1282c19:dd:d9:dd:c25:c25:dd18:6033
532c19:dd:d9:dd:c25:c25:dd18:6034/1282c19:dd:d9:dd:c25:c25:dd18:6034
542c19:dd:d9:dd:c25:c25:dd18:6035/1282c19:dd:d9:dd:c25:c25:dd18:6035
552c19:dd:d9:dd:c25:c25:dd18:6036/1282c19:dd:d9:dd:c25:c25:dd18:6036
562c19:dd:d9:dd:c25:c25:dd18:6037/1282c19:dd:d9:dd:c25:c25:dd18:6037
572c19:dd:d9:dd:c25:c25:dd18:6038/1282c19:dd:d9:dd:c25:c25:dd18:6038
582c19:dd:d9:dd:c25:c25:dd18:6039/1282c19:dd:d9:dd:c25:c25:dd18:6039
592c19:dd:d9:dd:c25:c25:dd18:603a/1282c19:dd:d9:dd:c25:c25:dd18:603a
602c19:dd:d9:dd:c25:c25:dd18:603b/1282c19:dd:d9:dd:c25:c25:dd18:603b
612c19:dd:d9:dd:c25:c25:dd18:603c/1282c19:dd:d9:dd:c25:c25:dd18:603c
622c19:dd:d9:dd:c25:c25:dd18:603d/1282c19:dd:d9:dd:c25:c25:dd18:603d
632c19:dd:d9:dd:c25:c25:dd18:603e/1282c19:dd:d9:dd:c25:c25:dd18:603e
642c19:dd:d9:dd:c25:c25:dd18:603f/1282c19:dd:d9:dd:c25:c25:dd18:603f
652c19:dd:d9:dd:c25:c25:dd18:6040/1282c19:dd:d9:dd:c25:c25:dd18:6040
662c19:dd:d9:dd:c25:c25:dd18:6041/1282c19:dd:d9:dd:c25:c25:dd18:6041
672c19:dd:d9:dd:c25:c25:dd18:6042/1282c19:dd:d9:dd:c25:c25:dd18:6042
682c19:dd:d9:dd:c25:c25:dd18:6043/1282c19:dd:d9:dd:c25:c25:dd18:6043
692c19:dd:d9:dd:c25:c25:dd18:6044/1282c19:dd:d9:dd:c25:c25:dd18:6044
702c19:dd:d9:dd:c25:c25:dd18:6045/1282c19:dd:d9:dd:c25:c25:dd18:6045
712c19:dd:d9:dd:c25:c25:dd18:6046/1282c19:dd:d9:dd:c25:c25:dd18:6046
722c19:dd:d9:dd:c25:c25:dd18:6047/1282c19:dd:d9:dd:c25:c25:dd18:6047
732c19:dd:d9:dd:c25:c25:dd18:6048/1282c19:dd:d9:dd:c25:c25:dd18:6048
742c19:dd:d9:dd:c25:c25:dd18:6049/1282c19:dd:d9:dd:c25:c25:dd18:6049
752c19:dd:d9:dd:c25:c25:dd18:604a/1282c19:dd:d9:dd:c25:c25:dd18:604a
762c19:dd:d9:dd:c25:c25:dd18:604b/1282c19:dd:d9:dd:c25:c25:dd18:604b
772c19:dd:d9:dd:c25:c25:dd18:604c/1282c19:dd:d9:dd:c25:c25:dd18:604c
782c19:dd:d9:dd:c25:c25:dd18:604d/1282c19:dd:d9:dd:c25:c25:dd18:604d
792c19:dd:d9:dd:c25:c25:dd18:604e/1282c19:dd:d9:dd:c25:c25:dd18:604e
802c19:dd:d9:dd:c25:c25:dd18:604f/1282c19:dd:d9:dd:c25:c25:dd18:604f
812c19:dd:d9:dd:c25:c25:dd18:6050/1282c19:dd:d9:dd:c25:c25:dd18:6050
822c19:dd:d9:dd:c25:c25:dd18:6051/1282c19:dd:d9:dd:c25:c25:dd18:6051
832c19:dd:d9:dd:c25:c25:dd18:6052/1282c19:dd:d9:dd:c25:c25:dd18:6052
842c19:dd:d9:dd:c25:c25:dd18:6053/1282c19:dd:d9:dd:c25:c25:dd18:6053
852c19:dd:d9:dd:c25:c25:dd18:6054/1282c19:dd:d9:dd:c25:c25:dd18:6054
862c19:dd:d9:dd:c25:c25:dd18:6055/1282c19:dd:d9:dd:c25:c25:dd18:6055
872c19:dd:d9:dd:c25:c25:dd18:6056/1282c19:dd:d9:dd:c25:c25:dd18:6056
882c19:dd:d9:dd:c25:c25:dd18:6057/1282c19:dd:d9:dd:c25:c25:dd18:6057
892c19:dd:d9:dd:c25:c25:dd18:6058/1282c19:dd:d9:dd:c25:c25:dd18:6058
902c19:dd:d9:dd:c25:c25:dd18:6059/1282c19:dd:d9:dd:c25:c25:dd18:6059
912c19:dd:d9:dd:c25:c25:dd18:605a/1282c19:dd:d9:dd:c25:c25:dd18:605a
922c19:dd:d9:dd:c25:c25:dd18:605b/1282c19:dd:d9:dd:c25:c25:dd18:605b
932c19:dd:d9:dd:c25:c25:dd18:605c/1282c19:dd:d9:dd:c25:c25:dd18:605c
942c19:dd:d9:dd:c25:c25:dd18:605d/1282c19:dd:d9:dd:c25:c25:dd18:605d
952c19:dd:d9:dd:c25:c25:dd18:605e/1282c19:dd:d9:dd:c25:c25:dd18:605e
962c19:dd:d9:dd:c25:c25:dd18:605f/1282c19:dd:d9:dd:c25:c25:dd18:605f
972c19:dd:d9:dd:c25:c25:dd18:6060/1282c19:dd:d9:dd:c25:c25:dd18:6060
982c19:dd:d9:dd:c25:c25:dd18:6061/1282c19:dd:d9:dd:c25:c25:dd18:6061
992c19:dd:d9:dd:c25:c25:dd18:6062/1282c19:dd:d9:dd:c25:c25:dd18:6062
1002c19:dd:d9:dd:c25:c25:dd18:6063/1282c19:dd:d9:dd:c25:c25:dd18:6063
1012c19:dd:d9:dd:c25:c25:dd18:6064/1282c19:dd:d9:dd:c25:c25:dd18:6064
1022c19:dd:d9:dd:c25:c25:dd18:6065/1282c19:dd:d9:dd:c25:c25:dd18:6065
1032c19:dd:d9:dd:c25:c25:dd18:6066/1282c19:dd:d9:dd:c25:c25:dd18:6066
1042c19:dd:d9:dd:c25:c25:dd18:6067/1282c19:dd:d9:dd:c25:c25:dd18:6067
1052c19:dd:d9:dd:c25:c25:dd18:6068/1282c19:dd:d9:dd:c25:c25:dd18:6068
1062c19:dd:d9:dd:c25:c25:dd18:6069/1282c19:dd:d9:dd:c25:c25:dd18:6069
1072c19:dd:d9:dd:c25:c25:dd18:606a/1282c19:dd:d9:dd:c25:c25:dd18:606a
1082c19:dd:d9:dd:c25:c25:dd18:606b/1282c19:dd:d9:dd:c25:c25:dd18:606b
1092c19:dd:d9:dd:c25:c25:dd18:606c/1282c19:dd:d9:dd:c25:c25:dd18:606c
1102c19:dd:d9:dd:c25:c25:dd18:606d/1282c19:dd:d9:dd:c25:c25:dd18:606d
1112c19:dd:d9:dd:c25:c25:dd18:606e/1282c19:dd:d9:dd:c25:c25:dd18:606e
1122c19:dd:d9:dd:c25:c25:dd18:606f/1282c19:dd:d9:dd:c25:c25:dd18:606f
1132c19:dd:d9:dd:c25:c25:dd18:6070/1282c19:dd:d9:dd:c25:c25:dd18:6070
1142c19:dd:d9:dd:c25:c25:dd18:6071/1282c19:dd:d9:dd:c25:c25:dd18:6071
1152c19:dd:d9:dd:c25:c25:dd18:6072/1282c19:dd:d9:dd:c25:c25:dd18:6072
1162c19:dd:d9:dd:c25:c25:dd18:6073/1282c19:dd:d9:dd:c25:c25:dd18:6073
1172c19:dd:d9:dd:c25:c25:dd18:6074/1282c19:dd:d9:dd:c25:c25:dd18:6074
1182c19:dd:d9:dd:c25:c25:dd18:6075/1282c19:dd:d9:dd:c25:c25:dd18:6075
1192c19:dd:d9:dd:c25:c25:dd18:6076/1282c19:dd:d9:dd:c25:c25:dd18:6076
1202c19:dd:d9:dd:c25:c25:dd18:6077/1282c19:dd:d9:dd:c25:c25:dd18:6077
1212c19:dd:d9:dd:c25:c25:dd18:6078/1282c19:dd:d9:dd:c25:c25:dd18:6078
1222c19:dd:d9:dd:c25:c25:dd18:6079/1282c19:dd:d9:dd:c25:c25:dd18:6079
1232c19:dd:d9:dd:c25:c25:dd18:607a/1282c19:dd:d9:dd:c25:c25:dd18:607a
1242c19:dd:d9:dd:c25:c25:dd18:607b/1282c19:dd:d9:dd:c25:c25:dd18:607b
1252c19:dd:d9:dd:c25:c25:dd18:607c/1282c19:dd:d9:dd:c25:c25:dd18:607c
1262c19:dd:d9:dd:c25:c25:dd18:607d/1282c19:dd:d9:dd:c25:c25:dd18:607d
1272c19:dd:d9:dd:c25:c25:dd18:607e/1282c19:dd:d9:dd:c25:c25:dd18:607e
1282c19:dd:d9:dd:c25:c25:dd18:607f/1282c19:dd:d9:dd:c25:c25:dd18:607f
1292c19:dd:d9:dd:c25:c25:dd18:6080/1282c19:dd:d9:dd:c25:c25:dd18:6080
1302c19:dd:d9:dd:c25:c25:dd18:6081/1282c19:dd:d9:dd:c25:c25:dd18:6081
1312c19:dd:d9:dd:c25:c25:dd18:6082/1282c19:dd:d9:dd:c25:c25:dd18:6082
1322c19:dd:d9:dd:c25:c25:dd18:6083/1282c19:dd:d9:dd:c25:c25:dd18:6083
1332c19:dd:d9:dd:c25:c25:dd18:6084/1282c19:dd:d9:dd:c25:c25:dd18:6084
1342c19:dd:d9:dd:c25:c25:dd18:6085/1282c19:dd:d9:dd:c25:c25:dd18:6085
1352c19:dd:d9:dd:c25:c25:dd18:6086/1282c19:dd:d9:dd:c25:c25:dd18:6086
1362c19:dd:d9:dd:c25:c25:dd18:6087/1282c19:dd:d9:dd:c25:c25:dd18:6087
1372c19:dd:d9:dd:c25:c25:dd18:6088/1282c19:dd:d9:dd:c25:c25:dd18:6088
1382c19:dd:d9:dd:c25:c25:dd18:6089/1282c19:dd:d9:dd:c25:c25:dd18:6089
1392c19:dd:d9:dd:c25:c25:dd18:608a/1282c19:dd:d9:dd:c25:c25:dd18:608a
1402c19:dd:d9:dd:c25:c25:dd18:608b/1282c19:dd:d9:dd:c25:c25:dd18:608b
1412c19:dd:d9:dd:c25:c25:dd18:608c/1282c19:dd:d9:dd:c25:c25:dd18:608c
1422c19:dd:d9:dd:c25:c25:dd18:608d/1282c19:dd:d9:dd:c25:c25:dd18:608d
1432c19:dd:d9:dd:c25:c25:dd18:608e/1282c19:dd:d9:dd:c25:c25:dd18:608e
1442c19:dd:d9:dd:c25:c25:dd18:608f/1282c19:dd:d9:dd:c25:c25:dd18:608f
1452c19:dd:d9:dd:c25:c25:dd18:6090/1282c19:dd:d9:dd:c25:c25:dd18:6090
1462c19:dd:d9:dd:c25:c25:dd18:6091/1282c19:dd:d9:dd:c25:c25:dd18:6091
1472c19:dd:d9:dd:c25:c25:dd18:6092/1282c19:dd:d9:dd:c25:c25:dd18:6092
1482c19:dd:d9:dd:c25:c25:dd18:6093/1282c19:dd:d9:dd:c25:c25:dd18:6093
1492c19:dd:d9:dd:c25:c25:dd18:6094/1282c19:dd:d9:dd:c25:c25:dd18:6094
1502c19:dd:d9:dd:c25:c25:dd18:6095/1282c19:dd:d9:dd:c25:c25:dd18:6095
1512c19:dd:d9:dd:c25:c25:dd18:6096/1282c19:dd:d9:dd:c25:c25:dd18:6096
1522c19:dd:d9:dd:c25:c25:dd18:6097/1282c19:dd:d9:dd:c25:c25:dd18:6097
1532c19:dd:d9:dd:c25:c25:dd18:6098/1282c19:dd:d9:dd:c25:c25:dd18:6098
1542c19:dd:d9:dd:c25:c25:dd18:6099/1282c19:dd:d9:dd:c25:c25:dd18:6099
1552c19:dd:d9:dd:c25:c25:dd18:609a/1282c19:dd:d9:dd:c25:c25:dd18:609a
1562c19:dd:d9:dd:c25:c25:dd18:609b/1282c19:dd:d9:dd:c25:c25:dd18:609b
1572c19:dd:d9:dd:c25:c25:dd18:609c/1282c19:dd:d9:dd:c25:c25:dd18:609c
1582c19:dd:d9:dd:c25:c25:dd18:609d/1282c19:dd:d9:dd:c25:c25:dd18:609d
1592c19:dd:d9:dd:c25:c25:dd18:609e/1282c19:dd:d9:dd:c25:c25:dd18:609e
1602c19:dd:d9:dd:c25:c25:dd18:609f/1282c19:dd:d9:dd:c25:c25:dd18:609f
1612c19:dd:d9:dd:c25:c25:dd18:60a0/1282c19:dd:d9:dd:c25:c25:dd18:60a0
1622c19:dd:d9:dd:c25:c25:dd18:60a1/1282c19:dd:d9:dd:c25:c25:dd18:60a1
1632c19:dd:d9:dd:c25:c25:dd18:60a2/1282c19:dd:d9:dd:c25:c25:dd18:60a2
1642c19:dd:d9:dd:c25:c25:dd18:60a3/1282c19:dd:d9:dd:c25:c25:dd18:60a3
1652c19:dd:d9:dd:c25:c25:dd18:60a4/1282c19:dd:d9:dd:c25:c25:dd18:60a4
1662c19:dd:d9:dd:c25:c25:dd18:60a5/1282c19:dd:d9:dd:c25:c25:dd18:60a5
1672c19:dd:d9:dd:c25:c25:dd18:60a6/1282c19:dd:d9:dd:c25:c25:dd18:60a6
1682c19:dd:d9:dd:c25:c25:dd18:60a7/1282c19:dd:d9:dd:c25:c25:dd18:60a7
1692c19:dd:d9:dd:c25:c25:dd18:60a8/1282c19:dd:d9:dd:c25:c25:dd18:60a8
1702c19:dd:d9:dd:c25:c25:dd18:60a9/1282c19:dd:d9:dd:c25:c25:dd18:60a9
1712c19:dd:d9:dd:c25:c25:dd18:60aa/1282c19:dd:d9:dd:c25:c25:dd18:60aa
1722c19:dd:d9:dd:c25:c25:dd18:60ab/1282c19:dd:d9:dd:c25:c25:dd18:60ab
1732c19:dd:d9:dd:c25:c25:dd18:60ac/1282c19:dd:d9:dd:c25:c25:dd18:60ac
1742c19:dd:d9:dd:c25:c25:dd18:60ad/1282c19:dd:d9:dd:c25:c25:dd18:60ad
1752c19:dd:d9:dd:c25:c25:dd18:60ae/1282c19:dd:d9:dd:c25:c25:dd18:60ae
1762c19:dd:d9:dd:c25:c25:dd18:60af/1282c19:dd:d9:dd:c25:c25:dd18:60af
1772c19:dd:d9:dd:c25:c25:dd18:60b0/1282c19:dd:d9:dd:c25:c25:dd18:60b0
1782c19:dd:d9:dd:c25:c25:dd18:60b1/1282c19:dd:d9:dd:c25:c25:dd18:60b1
1792c19:dd:d9:dd:c25:c25:dd18:60b2/1282c19:dd:d9:dd:c25:c25:dd18:60b2
1802c19:dd:d9:dd:c25:c25:dd18:60b3/1282c19:dd:d9:dd:c25:c25:dd18:60b3
1812c19:dd:d9:dd:c25:c25:dd18:60b4/1282c19:dd:d9:dd:c25:c25:dd18:60b4
1822c19:dd:d9:dd:c25:c25:dd18:60b5/1282c19:dd:d9:dd:c25:c25:dd18:60b5
1832c19:dd:d9:dd:c25:c25:dd18:60b6/1282c19:dd:d9:dd:c25:c25:dd18:60b6
1842c19:dd:d9:dd:c25:c25:dd18:60b7/1282c19:dd:d9:dd:c25:c25:dd18:60b7
1852c19:dd:d9:dd:c25:c25:dd18:60b8/1282c19:dd:d9:dd:c25:c25:dd18:60b8
1862c19:dd:d9:dd:c25:c25:dd18:60b9/1282c19:dd:d9:dd:c25:c25:dd18:60b9
1872c19:dd:d9:dd:c25:c25:dd18:60ba/1282c19:dd:d9:dd:c25:c25:dd18:60ba
1882c19:dd:d9:dd:c25:c25:dd18:60bb/1282c19:dd:d9:dd:c25:c25:dd18:60bb
1892c19:dd:d9:dd:c25:c25:dd18:60bc/1282c19:dd:d9:dd:c25:c25:dd18:60bc
1902c19:dd:d9:dd:c25:c25:dd18:60bd/1282c19:dd:d9:dd:c25:c25:dd18:60bd
1912c19:dd:d9:dd:c25:c25:dd18:60be/1282c19:dd:d9:dd:c25:c25:dd18:60be
1922c19:dd:d9:dd:c25:c25:dd18:60bf/1282c19:dd:d9:dd:c25:c25:dd18:60bf
1932c19:dd:d9:dd:c25:c25:dd18:60c0/1282c19:dd:d9:dd:c25:c25:dd18:60c0
1942c19:dd:d9:dd:c25:c25:dd18:60c1/1282c19:dd:d9:dd:c25:c25:dd18:60c1
1952c19:dd:d9:dd:c25:c25:dd18:60c2/1282c19:dd:d9:dd:c25:c25:dd18:60c2
1962c19:dd:d9:dd:c25:c25:dd18:60c3/1282c19:dd:d9:dd:c25:c25:dd18:60c3
1972c19:dd:d9:dd:c25:c25:dd18:60c4/1282c19:dd:d9:dd:c25:c25:dd18:60c4
1982c19:dd:d9:dd:c25:c25:dd18:60c5/1282c19:dd:d9:dd:c25:c25:dd18:60c5
1992c19:dd:d9:dd:c25:c25:dd18:60c6/1282c19:dd:d9:dd:c25:c25:dd18:60c6
2002c19:dd:d9:dd:c25:c25:dd18:60c7/1282c19:dd:d9:dd:c25:c25:dd18:60c7
2012c19:dd:d9:dd:c25:c25:dd18:60c8/1282c19:dd:d9:dd:c25:c25:dd18:60c8
2022c19:dd:d9:dd:c25:c25:dd18:60c9/1282c19:dd:d9:dd:c25:c25:dd18:60c9
2032c19:dd:d9:dd:c25:c25:dd18:60ca/1282c19:dd:d9:dd:c25:c25:dd18:60ca
2042c19:dd:d9:dd:c25:c25:dd18:60cb/1282c19:dd:d9:dd:c25:c25:dd18:60cb
2052c19:dd:d9:dd:c25:c25:dd18:60cc/1282c19:dd:d9:dd:c25:c25:dd18:60cc
2062c19:dd:d9:dd:c25:c25:dd18:60cd/1282c19:dd:d9:dd:c25:c25:dd18:60cd
2072c19:dd:d9:dd:c25:c25:dd18:60ce/1282c19:dd:d9:dd:c25:c25:dd18:60ce
2082c19:dd:d9:dd:c25:c25:dd18:60cf/1282c19:dd:d9:dd:c25:c25:dd18:60cf
2092c19:dd:d9:dd:c25:c25:dd18:60d0/1282c19:dd:d9:dd:c25:c25:dd18:60d0
2102c19:dd:d9:dd:c25:c25:dd18:60d1/1282c19:dd:d9:dd:c25:c25:dd18:60d1
2112c19:dd:d9:dd:c25:c25:dd18:60d2/1282c19:dd:d9:dd:c25:c25:dd18:60d2
2122c19:dd:d9:dd:c25:c25:dd18:60d3/1282c19:dd:d9:dd:c25:c25:dd18:60d3
2132c19:dd:d9:dd:c25:c25:dd18:60d4/1282c19:dd:d9:dd:c25:c25:dd18:60d4
2142c19:dd:d9:dd:c25:c25:dd18:60d5/1282c19:dd:d9:dd:c25:c25:dd18:60d5
2152c19:dd:d9:dd:c25:c25:dd18:60d6/1282c19:dd:d9:dd:c25:c25:dd18:60d6
2162c19:dd:d9:dd:c25:c25:dd18:60d7/1282c19:dd:d9:dd:c25:c25:dd18:60d7
2172c19:dd:d9:dd:c25:c25:dd18:60d8/1282c19:dd:d9:dd:c25:c25:dd18:60d8
2182c19:dd:d9:dd:c25:c25:dd18:60d9/1282c19:dd:d9:dd:c25:c25:dd18:60d9
2192c19:dd:d9:dd:c25:c25:dd18:60da/1282c19:dd:d9:dd:c25:c25:dd18:60da
2202c19:dd:d9:dd:c25:c25:dd18:60db/1282c19:dd:d9:dd:c25:c25:dd18:60db
2212c19:dd:d9:dd:c25:c25:dd18:60dc/1282c19:dd:d9:dd:c25:c25:dd18:60dc
2222c19:dd:d9:dd:c25:c25:dd18:60dd/1282c19:dd:d9:dd:c25:c25:dd18:60dd
2232c19:dd:d9:dd:c25:c25:dd18:60de/1282c19:dd:d9:dd:c25:c25:dd18:60de
2242c19:dd:d9:dd:c25:c25:dd18:60df/1282c19:dd:d9:dd:c25:c25:dd18:60df
2252c19:dd:d9:dd:c25:c25:dd18:60e0/1282c19:dd:d9:dd:c25:c25:dd18:60e0
2262c19:dd:d9:dd:c25:c25:dd18:60e1/1282c19:dd:d9:dd:c25:c25:dd18:60e1
2272c19:dd:d9:dd:c25:c25:dd18:60e2/1282c19:dd:d9:dd:c25:c25:dd18:60e2
2282c19:dd:d9:dd:c25:c25:dd18:60e3/1282c19:dd:d9:dd:c25:c25:dd18:60e3
2292c19:dd:d9:dd:c25:c25:dd18:60e4/1282c19:dd:d9:dd:c25:c25:dd18:60e4
2302c19:dd:d9:dd:c25:c25:dd18:60e5/1282c19:dd:d9:dd:c25:c25:dd18:60e5
2312c19:dd:d9:dd:c25:c25:dd18:60e6/1282c19:dd:d9:dd:c25:c25:dd18:60e6
2322c19:dd:d9:dd:c25:c25:dd18:60e7/1282c19:dd:d9:dd:c25:c25:dd18:60e7
2332c19:dd:d9:dd:c25:c25:dd18:60e8/1282c19:dd:d9:dd:c25:c25:dd18:60e8
2342c19:dd:d9:dd:c25:c25:dd18:60e9/1282c19:dd:d9:dd:c25:c25:dd18:60e9
2352c19:dd:d9:dd:c25:c25:dd18:60ea/1282c19:dd:d9:dd:c25:c25:dd18:60ea
2362c19:dd:d9:dd:c25:c25:dd18:60eb/1282c19:dd:d9:dd:c25:c25:dd18:60eb
2372c19:dd:d9:dd:c25:c25:dd18:60ec/1282c19:dd:d9:dd:c25:c25:dd18:60ec
2382c19:dd:d9:dd:c25:c25:dd18:60ed/1282c19:dd:d9:dd:c25:c25:dd18:60ed
2392c19:dd:d9:dd:c25:c25:dd18:60ee/1282c19:dd:d9:dd:c25:c25:dd18:60ee
2402c19:dd:d9:dd:c25:c25:dd18:60ef/1282c19:dd:d9:dd:c25:c25:dd18:60ef
2412c19:dd:d9:dd:c25:c25:dd18:60f0/1282c19:dd:d9:dd:c25:c25:dd18:60f0
2422c19:dd:d9:dd:c25:c25:dd18:60f1/1282c19:dd:d9:dd:c25:c25:dd18:60f1
2432c19:dd:d9:dd:c25:c25:dd18:60f2/1282c19:dd:d9:dd:c25:c25:dd18:60f2
2442c19:dd:d9:dd:c25:c25:dd18:60f3/1282c19:dd:d9:dd:c25:c25:dd18:60f3
2452c19:dd:d9:dd:c25:c25:dd18:60f4/1282c19:dd:d9:dd:c25:c25:dd18:60f4
2462c19:dd:d9:dd:c25:c25:dd18:60f5/1282c19:dd:d9:dd:c25:c25:dd18:60f5
2472c19:dd:d9:dd:c25:c25:dd18:60f6/1282c19:dd:d9:dd:c25:c25:dd18:60f6
2482c19:dd:d9:dd:c25:c25:dd18:60f7/1282c19:dd:d9:dd:c25:c25:dd18:60f7
2492c19:dd:d9:dd:c25:c25:dd18:60f8/1282c19:dd:d9:dd:c25:c25:dd18:60f8
2502c19:dd:d9:dd:c25:c25:dd18:60f9/1282c19:dd:d9:dd:c25:c25:dd18:60f9
2512c19:dd:d9:dd:c25:c25:dd18:60fa/1282c19:dd:d9:dd:c25:c25:dd18:60fa
2522c19:dd:d9:dd:c25:c25:dd18:60fb/1282c19:dd:d9:dd:c25:c25:dd18:60fb
2532c19:dd:d9:dd:c25:c25:dd18:60fc/1282c19:dd:d9:dd:c25:c25:dd18:60fc
2542c19:dd:d9:dd:c25:c25:dd18:60fd/1282c19:dd:d9:dd:c25:c25:dd18:60fd
2552c19:dd:d9:dd:c25:c25:dd18:60fe/1282c19:dd:d9:dd:c25:c25:dd18:60fe
2562c19:dd:d9:dd:c25:c25:dd18:60ff/1282c19:dd:d9:dd:c25:c25:dd18:60ff

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.