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:c25:0:9000/116
First address
2c19:dd:d9:dd:c25:c25:0:9000
Last address
2c19:dd:d9:dd:c25:c25:0:9fff
Addresses
4,096
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:0000:9000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
9.0.0.0.0.5.2.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:c25:0:9000/116 makes 4,096 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:0:9000/1282c19:dd:d9:dd:c25:c25:0:9000
22c19:dd:d9:dd:c25:c25:0:9001/1282c19:dd:d9:dd:c25:c25:0:9001
32c19:dd:d9:dd:c25:c25:0:9002/1282c19:dd:d9:dd:c25:c25:0:9002
42c19:dd:d9:dd:c25:c25:0:9003/1282c19:dd:d9:dd:c25:c25:0:9003
52c19:dd:d9:dd:c25:c25:0:9004/1282c19:dd:d9:dd:c25:c25:0:9004
62c19:dd:d9:dd:c25:c25:0:9005/1282c19:dd:d9:dd:c25:c25:0:9005
72c19:dd:d9:dd:c25:c25:0:9006/1282c19:dd:d9:dd:c25:c25:0:9006
82c19:dd:d9:dd:c25:c25:0:9007/1282c19:dd:d9:dd:c25:c25:0:9007
92c19:dd:d9:dd:c25:c25:0:9008/1282c19:dd:d9:dd:c25:c25:0:9008
102c19:dd:d9:dd:c25:c25:0:9009/1282c19:dd:d9:dd:c25:c25:0:9009
112c19:dd:d9:dd:c25:c25:0:900a/1282c19:dd:d9:dd:c25:c25:0:900a
122c19:dd:d9:dd:c25:c25:0:900b/1282c19:dd:d9:dd:c25:c25:0:900b
132c19:dd:d9:dd:c25:c25:0:900c/1282c19:dd:d9:dd:c25:c25:0:900c
142c19:dd:d9:dd:c25:c25:0:900d/1282c19:dd:d9:dd:c25:c25:0:900d
152c19:dd:d9:dd:c25:c25:0:900e/1282c19:dd:d9:dd:c25:c25:0:900e
162c19:dd:d9:dd:c25:c25:0:900f/1282c19:dd:d9:dd:c25:c25:0:900f
172c19:dd:d9:dd:c25:c25:0:9010/1282c19:dd:d9:dd:c25:c25:0:9010
182c19:dd:d9:dd:c25:c25:0:9011/1282c19:dd:d9:dd:c25:c25:0:9011
192c19:dd:d9:dd:c25:c25:0:9012/1282c19:dd:d9:dd:c25:c25:0:9012
202c19:dd:d9:dd:c25:c25:0:9013/1282c19:dd:d9:dd:c25:c25:0:9013
212c19:dd:d9:dd:c25:c25:0:9014/1282c19:dd:d9:dd:c25:c25:0:9014
222c19:dd:d9:dd:c25:c25:0:9015/1282c19:dd:d9:dd:c25:c25:0:9015
232c19:dd:d9:dd:c25:c25:0:9016/1282c19:dd:d9:dd:c25:c25:0:9016
242c19:dd:d9:dd:c25:c25:0:9017/1282c19:dd:d9:dd:c25:c25:0:9017
252c19:dd:d9:dd:c25:c25:0:9018/1282c19:dd:d9:dd:c25:c25:0:9018
262c19:dd:d9:dd:c25:c25:0:9019/1282c19:dd:d9:dd:c25:c25:0:9019
272c19:dd:d9:dd:c25:c25:0:901a/1282c19:dd:d9:dd:c25:c25:0:901a
282c19:dd:d9:dd:c25:c25:0:901b/1282c19:dd:d9:dd:c25:c25:0:901b
292c19:dd:d9:dd:c25:c25:0:901c/1282c19:dd:d9:dd:c25:c25:0:901c
302c19:dd:d9:dd:c25:c25:0:901d/1282c19:dd:d9:dd:c25:c25:0:901d
312c19:dd:d9:dd:c25:c25:0:901e/1282c19:dd:d9:dd:c25:c25:0:901e
322c19:dd:d9:dd:c25:c25:0:901f/1282c19:dd:d9:dd:c25:c25:0:901f
332c19:dd:d9:dd:c25:c25:0:9020/1282c19:dd:d9:dd:c25:c25:0:9020
342c19:dd:d9:dd:c25:c25:0:9021/1282c19:dd:d9:dd:c25:c25:0:9021
352c19:dd:d9:dd:c25:c25:0:9022/1282c19:dd:d9:dd:c25:c25:0:9022
362c19:dd:d9:dd:c25:c25:0:9023/1282c19:dd:d9:dd:c25:c25:0:9023
372c19:dd:d9:dd:c25:c25:0:9024/1282c19:dd:d9:dd:c25:c25:0:9024
382c19:dd:d9:dd:c25:c25:0:9025/1282c19:dd:d9:dd:c25:c25:0:9025
392c19:dd:d9:dd:c25:c25:0:9026/1282c19:dd:d9:dd:c25:c25:0:9026
402c19:dd:d9:dd:c25:c25:0:9027/1282c19:dd:d9:dd:c25:c25:0:9027
412c19:dd:d9:dd:c25:c25:0:9028/1282c19:dd:d9:dd:c25:c25:0:9028
422c19:dd:d9:dd:c25:c25:0:9029/1282c19:dd:d9:dd:c25:c25:0:9029
432c19:dd:d9:dd:c25:c25:0:902a/1282c19:dd:d9:dd:c25:c25:0:902a
442c19:dd:d9:dd:c25:c25:0:902b/1282c19:dd:d9:dd:c25:c25:0:902b
452c19:dd:d9:dd:c25:c25:0:902c/1282c19:dd:d9:dd:c25:c25:0:902c
462c19:dd:d9:dd:c25:c25:0:902d/1282c19:dd:d9:dd:c25:c25:0:902d
472c19:dd:d9:dd:c25:c25:0:902e/1282c19:dd:d9:dd:c25:c25:0:902e
482c19:dd:d9:dd:c25:c25:0:902f/1282c19:dd:d9:dd:c25:c25:0:902f
492c19:dd:d9:dd:c25:c25:0:9030/1282c19:dd:d9:dd:c25:c25:0:9030
502c19:dd:d9:dd:c25:c25:0:9031/1282c19:dd:d9:dd:c25:c25:0:9031
512c19:dd:d9:dd:c25:c25:0:9032/1282c19:dd:d9:dd:c25:c25:0:9032
522c19:dd:d9:dd:c25:c25:0:9033/1282c19:dd:d9:dd:c25:c25:0:9033
532c19:dd:d9:dd:c25:c25:0:9034/1282c19:dd:d9:dd:c25:c25:0:9034
542c19:dd:d9:dd:c25:c25:0:9035/1282c19:dd:d9:dd:c25:c25:0:9035
552c19:dd:d9:dd:c25:c25:0:9036/1282c19:dd:d9:dd:c25:c25:0:9036
562c19:dd:d9:dd:c25:c25:0:9037/1282c19:dd:d9:dd:c25:c25:0:9037
572c19:dd:d9:dd:c25:c25:0:9038/1282c19:dd:d9:dd:c25:c25:0:9038
582c19:dd:d9:dd:c25:c25:0:9039/1282c19:dd:d9:dd:c25:c25:0:9039
592c19:dd:d9:dd:c25:c25:0:903a/1282c19:dd:d9:dd:c25:c25:0:903a
602c19:dd:d9:dd:c25:c25:0:903b/1282c19:dd:d9:dd:c25:c25:0:903b
612c19:dd:d9:dd:c25:c25:0:903c/1282c19:dd:d9:dd:c25:c25:0:903c
622c19:dd:d9:dd:c25:c25:0:903d/1282c19:dd:d9:dd:c25:c25:0:903d
632c19:dd:d9:dd:c25:c25:0:903e/1282c19:dd:d9:dd:c25:c25:0:903e
642c19:dd:d9:dd:c25:c25:0:903f/1282c19:dd:d9:dd:c25:c25:0:903f
652c19:dd:d9:dd:c25:c25:0:9040/1282c19:dd:d9:dd:c25:c25:0:9040
662c19:dd:d9:dd:c25:c25:0:9041/1282c19:dd:d9:dd:c25:c25:0:9041
672c19:dd:d9:dd:c25:c25:0:9042/1282c19:dd:d9:dd:c25:c25:0:9042
682c19:dd:d9:dd:c25:c25:0:9043/1282c19:dd:d9:dd:c25:c25:0:9043
692c19:dd:d9:dd:c25:c25:0:9044/1282c19:dd:d9:dd:c25:c25:0:9044
702c19:dd:d9:dd:c25:c25:0:9045/1282c19:dd:d9:dd:c25:c25:0:9045
712c19:dd:d9:dd:c25:c25:0:9046/1282c19:dd:d9:dd:c25:c25:0:9046
722c19:dd:d9:dd:c25:c25:0:9047/1282c19:dd:d9:dd:c25:c25:0:9047
732c19:dd:d9:dd:c25:c25:0:9048/1282c19:dd:d9:dd:c25:c25:0:9048
742c19:dd:d9:dd:c25:c25:0:9049/1282c19:dd:d9:dd:c25:c25:0:9049
752c19:dd:d9:dd:c25:c25:0:904a/1282c19:dd:d9:dd:c25:c25:0:904a
762c19:dd:d9:dd:c25:c25:0:904b/1282c19:dd:d9:dd:c25:c25:0:904b
772c19:dd:d9:dd:c25:c25:0:904c/1282c19:dd:d9:dd:c25:c25:0:904c
782c19:dd:d9:dd:c25:c25:0:904d/1282c19:dd:d9:dd:c25:c25:0:904d
792c19:dd:d9:dd:c25:c25:0:904e/1282c19:dd:d9:dd:c25:c25:0:904e
802c19:dd:d9:dd:c25:c25:0:904f/1282c19:dd:d9:dd:c25:c25:0:904f
812c19:dd:d9:dd:c25:c25:0:9050/1282c19:dd:d9:dd:c25:c25:0:9050
822c19:dd:d9:dd:c25:c25:0:9051/1282c19:dd:d9:dd:c25:c25:0:9051
832c19:dd:d9:dd:c25:c25:0:9052/1282c19:dd:d9:dd:c25:c25:0:9052
842c19:dd:d9:dd:c25:c25:0:9053/1282c19:dd:d9:dd:c25:c25:0:9053
852c19:dd:d9:dd:c25:c25:0:9054/1282c19:dd:d9:dd:c25:c25:0:9054
862c19:dd:d9:dd:c25:c25:0:9055/1282c19:dd:d9:dd:c25:c25:0:9055
872c19:dd:d9:dd:c25:c25:0:9056/1282c19:dd:d9:dd:c25:c25:0:9056
882c19:dd:d9:dd:c25:c25:0:9057/1282c19:dd:d9:dd:c25:c25:0:9057
892c19:dd:d9:dd:c25:c25:0:9058/1282c19:dd:d9:dd:c25:c25:0:9058
902c19:dd:d9:dd:c25:c25:0:9059/1282c19:dd:d9:dd:c25:c25:0:9059
912c19:dd:d9:dd:c25:c25:0:905a/1282c19:dd:d9:dd:c25:c25:0:905a
922c19:dd:d9:dd:c25:c25:0:905b/1282c19:dd:d9:dd:c25:c25:0:905b
932c19:dd:d9:dd:c25:c25:0:905c/1282c19:dd:d9:dd:c25:c25:0:905c
942c19:dd:d9:dd:c25:c25:0:905d/1282c19:dd:d9:dd:c25:c25:0:905d
952c19:dd:d9:dd:c25:c25:0:905e/1282c19:dd:d9:dd:c25:c25:0:905e
962c19:dd:d9:dd:c25:c25:0:905f/1282c19:dd:d9:dd:c25:c25:0:905f
972c19:dd:d9:dd:c25:c25:0:9060/1282c19:dd:d9:dd:c25:c25:0:9060
982c19:dd:d9:dd:c25:c25:0:9061/1282c19:dd:d9:dd:c25:c25:0:9061
992c19:dd:d9:dd:c25:c25:0:9062/1282c19:dd:d9:dd:c25:c25:0:9062
1002c19:dd:d9:dd:c25:c25:0:9063/1282c19:dd:d9:dd:c25:c25:0:9063
1012c19:dd:d9:dd:c25:c25:0:9064/1282c19:dd:d9:dd:c25:c25:0:9064
1022c19:dd:d9:dd:c25:c25:0:9065/1282c19:dd:d9:dd:c25:c25:0:9065
1032c19:dd:d9:dd:c25:c25:0:9066/1282c19:dd:d9:dd:c25:c25:0:9066
1042c19:dd:d9:dd:c25:c25:0:9067/1282c19:dd:d9:dd:c25:c25:0:9067
1052c19:dd:d9:dd:c25:c25:0:9068/1282c19:dd:d9:dd:c25:c25:0:9068
1062c19:dd:d9:dd:c25:c25:0:9069/1282c19:dd:d9:dd:c25:c25:0:9069
1072c19:dd:d9:dd:c25:c25:0:906a/1282c19:dd:d9:dd:c25:c25:0:906a
1082c19:dd:d9:dd:c25:c25:0:906b/1282c19:dd:d9:dd:c25:c25:0:906b
1092c19:dd:d9:dd:c25:c25:0:906c/1282c19:dd:d9:dd:c25:c25:0:906c
1102c19:dd:d9:dd:c25:c25:0:906d/1282c19:dd:d9:dd:c25:c25:0:906d
1112c19:dd:d9:dd:c25:c25:0:906e/1282c19:dd:d9:dd:c25:c25:0:906e
1122c19:dd:d9:dd:c25:c25:0:906f/1282c19:dd:d9:dd:c25:c25:0:906f
1132c19:dd:d9:dd:c25:c25:0:9070/1282c19:dd:d9:dd:c25:c25:0:9070
1142c19:dd:d9:dd:c25:c25:0:9071/1282c19:dd:d9:dd:c25:c25:0:9071
1152c19:dd:d9:dd:c25:c25:0:9072/1282c19:dd:d9:dd:c25:c25:0:9072
1162c19:dd:d9:dd:c25:c25:0:9073/1282c19:dd:d9:dd:c25:c25:0:9073
1172c19:dd:d9:dd:c25:c25:0:9074/1282c19:dd:d9:dd:c25:c25:0:9074
1182c19:dd:d9:dd:c25:c25:0:9075/1282c19:dd:d9:dd:c25:c25:0:9075
1192c19:dd:d9:dd:c25:c25:0:9076/1282c19:dd:d9:dd:c25:c25:0:9076
1202c19:dd:d9:dd:c25:c25:0:9077/1282c19:dd:d9:dd:c25:c25:0:9077
1212c19:dd:d9:dd:c25:c25:0:9078/1282c19:dd:d9:dd:c25:c25:0:9078
1222c19:dd:d9:dd:c25:c25:0:9079/1282c19:dd:d9:dd:c25:c25:0:9079
1232c19:dd:d9:dd:c25:c25:0:907a/1282c19:dd:d9:dd:c25:c25:0:907a
1242c19:dd:d9:dd:c25:c25:0:907b/1282c19:dd:d9:dd:c25:c25:0:907b
1252c19:dd:d9:dd:c25:c25:0:907c/1282c19:dd:d9:dd:c25:c25:0:907c
1262c19:dd:d9:dd:c25:c25:0:907d/1282c19:dd:d9:dd:c25:c25:0:907d
1272c19:dd:d9:dd:c25:c25:0:907e/1282c19:dd:d9:dd:c25:c25:0:907e
1282c19:dd:d9:dd:c25:c25:0:907f/1282c19:dd:d9:dd:c25:c25:0:907f
1292c19:dd:d9:dd:c25:c25:0:9080/1282c19:dd:d9:dd:c25:c25:0:9080
1302c19:dd:d9:dd:c25:c25:0:9081/1282c19:dd:d9:dd:c25:c25:0:9081
1312c19:dd:d9:dd:c25:c25:0:9082/1282c19:dd:d9:dd:c25:c25:0:9082
1322c19:dd:d9:dd:c25:c25:0:9083/1282c19:dd:d9:dd:c25:c25:0:9083
1332c19:dd:d9:dd:c25:c25:0:9084/1282c19:dd:d9:dd:c25:c25:0:9084
1342c19:dd:d9:dd:c25:c25:0:9085/1282c19:dd:d9:dd:c25:c25:0:9085
1352c19:dd:d9:dd:c25:c25:0:9086/1282c19:dd:d9:dd:c25:c25:0:9086
1362c19:dd:d9:dd:c25:c25:0:9087/1282c19:dd:d9:dd:c25:c25:0:9087
1372c19:dd:d9:dd:c25:c25:0:9088/1282c19:dd:d9:dd:c25:c25:0:9088
1382c19:dd:d9:dd:c25:c25:0:9089/1282c19:dd:d9:dd:c25:c25:0:9089
1392c19:dd:d9:dd:c25:c25:0:908a/1282c19:dd:d9:dd:c25:c25:0:908a
1402c19:dd:d9:dd:c25:c25:0:908b/1282c19:dd:d9:dd:c25:c25:0:908b
1412c19:dd:d9:dd:c25:c25:0:908c/1282c19:dd:d9:dd:c25:c25:0:908c
1422c19:dd:d9:dd:c25:c25:0:908d/1282c19:dd:d9:dd:c25:c25:0:908d
1432c19:dd:d9:dd:c25:c25:0:908e/1282c19:dd:d9:dd:c25:c25:0:908e
1442c19:dd:d9:dd:c25:c25:0:908f/1282c19:dd:d9:dd:c25:c25:0:908f
1452c19:dd:d9:dd:c25:c25:0:9090/1282c19:dd:d9:dd:c25:c25:0:9090
1462c19:dd:d9:dd:c25:c25:0:9091/1282c19:dd:d9:dd:c25:c25:0:9091
1472c19:dd:d9:dd:c25:c25:0:9092/1282c19:dd:d9:dd:c25:c25:0:9092
1482c19:dd:d9:dd:c25:c25:0:9093/1282c19:dd:d9:dd:c25:c25:0:9093
1492c19:dd:d9:dd:c25:c25:0:9094/1282c19:dd:d9:dd:c25:c25:0:9094
1502c19:dd:d9:dd:c25:c25:0:9095/1282c19:dd:d9:dd:c25:c25:0:9095
1512c19:dd:d9:dd:c25:c25:0:9096/1282c19:dd:d9:dd:c25:c25:0:9096
1522c19:dd:d9:dd:c25:c25:0:9097/1282c19:dd:d9:dd:c25:c25:0:9097
1532c19:dd:d9:dd:c25:c25:0:9098/1282c19:dd:d9:dd:c25:c25:0:9098
1542c19:dd:d9:dd:c25:c25:0:9099/1282c19:dd:d9:dd:c25:c25:0:9099
1552c19:dd:d9:dd:c25:c25:0:909a/1282c19:dd:d9:dd:c25:c25:0:909a
1562c19:dd:d9:dd:c25:c25:0:909b/1282c19:dd:d9:dd:c25:c25:0:909b
1572c19:dd:d9:dd:c25:c25:0:909c/1282c19:dd:d9:dd:c25:c25:0:909c
1582c19:dd:d9:dd:c25:c25:0:909d/1282c19:dd:d9:dd:c25:c25:0:909d
1592c19:dd:d9:dd:c25:c25:0:909e/1282c19:dd:d9:dd:c25:c25:0:909e
1602c19:dd:d9:dd:c25:c25:0:909f/1282c19:dd:d9:dd:c25:c25:0:909f
1612c19:dd:d9:dd:c25:c25:0:90a0/1282c19:dd:d9:dd:c25:c25:0:90a0
1622c19:dd:d9:dd:c25:c25:0:90a1/1282c19:dd:d9:dd:c25:c25:0:90a1
1632c19:dd:d9:dd:c25:c25:0:90a2/1282c19:dd:d9:dd:c25:c25:0:90a2
1642c19:dd:d9:dd:c25:c25:0:90a3/1282c19:dd:d9:dd:c25:c25:0:90a3
1652c19:dd:d9:dd:c25:c25:0:90a4/1282c19:dd:d9:dd:c25:c25:0:90a4
1662c19:dd:d9:dd:c25:c25:0:90a5/1282c19:dd:d9:dd:c25:c25:0:90a5
1672c19:dd:d9:dd:c25:c25:0:90a6/1282c19:dd:d9:dd:c25:c25:0:90a6
1682c19:dd:d9:dd:c25:c25:0:90a7/1282c19:dd:d9:dd:c25:c25:0:90a7
1692c19:dd:d9:dd:c25:c25:0:90a8/1282c19:dd:d9:dd:c25:c25:0:90a8
1702c19:dd:d9:dd:c25:c25:0:90a9/1282c19:dd:d9:dd:c25:c25:0:90a9
1712c19:dd:d9:dd:c25:c25:0:90aa/1282c19:dd:d9:dd:c25:c25:0:90aa
1722c19:dd:d9:dd:c25:c25:0:90ab/1282c19:dd:d9:dd:c25:c25:0:90ab
1732c19:dd:d9:dd:c25:c25:0:90ac/1282c19:dd:d9:dd:c25:c25:0:90ac
1742c19:dd:d9:dd:c25:c25:0:90ad/1282c19:dd:d9:dd:c25:c25:0:90ad
1752c19:dd:d9:dd:c25:c25:0:90ae/1282c19:dd:d9:dd:c25:c25:0:90ae
1762c19:dd:d9:dd:c25:c25:0:90af/1282c19:dd:d9:dd:c25:c25:0:90af
1772c19:dd:d9:dd:c25:c25:0:90b0/1282c19:dd:d9:dd:c25:c25:0:90b0
1782c19:dd:d9:dd:c25:c25:0:90b1/1282c19:dd:d9:dd:c25:c25:0:90b1
1792c19:dd:d9:dd:c25:c25:0:90b2/1282c19:dd:d9:dd:c25:c25:0:90b2
1802c19:dd:d9:dd:c25:c25:0:90b3/1282c19:dd:d9:dd:c25:c25:0:90b3
1812c19:dd:d9:dd:c25:c25:0:90b4/1282c19:dd:d9:dd:c25:c25:0:90b4
1822c19:dd:d9:dd:c25:c25:0:90b5/1282c19:dd:d9:dd:c25:c25:0:90b5
1832c19:dd:d9:dd:c25:c25:0:90b6/1282c19:dd:d9:dd:c25:c25:0:90b6
1842c19:dd:d9:dd:c25:c25:0:90b7/1282c19:dd:d9:dd:c25:c25:0:90b7
1852c19:dd:d9:dd:c25:c25:0:90b8/1282c19:dd:d9:dd:c25:c25:0:90b8
1862c19:dd:d9:dd:c25:c25:0:90b9/1282c19:dd:d9:dd:c25:c25:0:90b9
1872c19:dd:d9:dd:c25:c25:0:90ba/1282c19:dd:d9:dd:c25:c25:0:90ba
1882c19:dd:d9:dd:c25:c25:0:90bb/1282c19:dd:d9:dd:c25:c25:0:90bb
1892c19:dd:d9:dd:c25:c25:0:90bc/1282c19:dd:d9:dd:c25:c25:0:90bc
1902c19:dd:d9:dd:c25:c25:0:90bd/1282c19:dd:d9:dd:c25:c25:0:90bd
1912c19:dd:d9:dd:c25:c25:0:90be/1282c19:dd:d9:dd:c25:c25:0:90be
1922c19:dd:d9:dd:c25:c25:0:90bf/1282c19:dd:d9:dd:c25:c25:0:90bf
1932c19:dd:d9:dd:c25:c25:0:90c0/1282c19:dd:d9:dd:c25:c25:0:90c0
1942c19:dd:d9:dd:c25:c25:0:90c1/1282c19:dd:d9:dd:c25:c25:0:90c1
1952c19:dd:d9:dd:c25:c25:0:90c2/1282c19:dd:d9:dd:c25:c25:0:90c2
1962c19:dd:d9:dd:c25:c25:0:90c3/1282c19:dd:d9:dd:c25:c25:0:90c3
1972c19:dd:d9:dd:c25:c25:0:90c4/1282c19:dd:d9:dd:c25:c25:0:90c4
1982c19:dd:d9:dd:c25:c25:0:90c5/1282c19:dd:d9:dd:c25:c25:0:90c5
1992c19:dd:d9:dd:c25:c25:0:90c6/1282c19:dd:d9:dd:c25:c25:0:90c6
2002c19:dd:d9:dd:c25:c25:0:90c7/1282c19:dd:d9:dd:c25:c25:0:90c7
2012c19:dd:d9:dd:c25:c25:0:90c8/1282c19:dd:d9:dd:c25:c25:0:90c8
2022c19:dd:d9:dd:c25:c25:0:90c9/1282c19:dd:d9:dd:c25:c25:0:90c9
2032c19:dd:d9:dd:c25:c25:0:90ca/1282c19:dd:d9:dd:c25:c25:0:90ca
2042c19:dd:d9:dd:c25:c25:0:90cb/1282c19:dd:d9:dd:c25:c25:0:90cb
2052c19:dd:d9:dd:c25:c25:0:90cc/1282c19:dd:d9:dd:c25:c25:0:90cc
2062c19:dd:d9:dd:c25:c25:0:90cd/1282c19:dd:d9:dd:c25:c25:0:90cd
2072c19:dd:d9:dd:c25:c25:0:90ce/1282c19:dd:d9:dd:c25:c25:0:90ce
2082c19:dd:d9:dd:c25:c25:0:90cf/1282c19:dd:d9:dd:c25:c25:0:90cf
2092c19:dd:d9:dd:c25:c25:0:90d0/1282c19:dd:d9:dd:c25:c25:0:90d0
2102c19:dd:d9:dd:c25:c25:0:90d1/1282c19:dd:d9:dd:c25:c25:0:90d1
2112c19:dd:d9:dd:c25:c25:0:90d2/1282c19:dd:d9:dd:c25:c25:0:90d2
2122c19:dd:d9:dd:c25:c25:0:90d3/1282c19:dd:d9:dd:c25:c25:0:90d3
2132c19:dd:d9:dd:c25:c25:0:90d4/1282c19:dd:d9:dd:c25:c25:0:90d4
2142c19:dd:d9:dd:c25:c25:0:90d5/1282c19:dd:d9:dd:c25:c25:0:90d5
2152c19:dd:d9:dd:c25:c25:0:90d6/1282c19:dd:d9:dd:c25:c25:0:90d6
2162c19:dd:d9:dd:c25:c25:0:90d7/1282c19:dd:d9:dd:c25:c25:0:90d7
2172c19:dd:d9:dd:c25:c25:0:90d8/1282c19:dd:d9:dd:c25:c25:0:90d8
2182c19:dd:d9:dd:c25:c25:0:90d9/1282c19:dd:d9:dd:c25:c25:0:90d9
2192c19:dd:d9:dd:c25:c25:0:90da/1282c19:dd:d9:dd:c25:c25:0:90da
2202c19:dd:d9:dd:c25:c25:0:90db/1282c19:dd:d9:dd:c25:c25:0:90db
2212c19:dd:d9:dd:c25:c25:0:90dc/1282c19:dd:d9:dd:c25:c25:0:90dc
2222c19:dd:d9:dd:c25:c25:0:90dd/1282c19:dd:d9:dd:c25:c25:0:90dd
2232c19:dd:d9:dd:c25:c25:0:90de/1282c19:dd:d9:dd:c25:c25:0:90de
2242c19:dd:d9:dd:c25:c25:0:90df/1282c19:dd:d9:dd:c25:c25:0:90df
2252c19:dd:d9:dd:c25:c25:0:90e0/1282c19:dd:d9:dd:c25:c25:0:90e0
2262c19:dd:d9:dd:c25:c25:0:90e1/1282c19:dd:d9:dd:c25:c25:0:90e1
2272c19:dd:d9:dd:c25:c25:0:90e2/1282c19:dd:d9:dd:c25:c25:0:90e2
2282c19:dd:d9:dd:c25:c25:0:90e3/1282c19:dd:d9:dd:c25:c25:0:90e3
2292c19:dd:d9:dd:c25:c25:0:90e4/1282c19:dd:d9:dd:c25:c25:0:90e4
2302c19:dd:d9:dd:c25:c25:0:90e5/1282c19:dd:d9:dd:c25:c25:0:90e5
2312c19:dd:d9:dd:c25:c25:0:90e6/1282c19:dd:d9:dd:c25:c25:0:90e6
2322c19:dd:d9:dd:c25:c25:0:90e7/1282c19:dd:d9:dd:c25:c25:0:90e7
2332c19:dd:d9:dd:c25:c25:0:90e8/1282c19:dd:d9:dd:c25:c25:0:90e8
2342c19:dd:d9:dd:c25:c25:0:90e9/1282c19:dd:d9:dd:c25:c25:0:90e9
2352c19:dd:d9:dd:c25:c25:0:90ea/1282c19:dd:d9:dd:c25:c25:0:90ea
2362c19:dd:d9:dd:c25:c25:0:90eb/1282c19:dd:d9:dd:c25:c25:0:90eb
2372c19:dd:d9:dd:c25:c25:0:90ec/1282c19:dd:d9:dd:c25:c25:0:90ec
2382c19:dd:d9:dd:c25:c25:0:90ed/1282c19:dd:d9:dd:c25:c25:0:90ed
2392c19:dd:d9:dd:c25:c25:0:90ee/1282c19:dd:d9:dd:c25:c25:0:90ee
2402c19:dd:d9:dd:c25:c25:0:90ef/1282c19:dd:d9:dd:c25:c25:0:90ef
2412c19:dd:d9:dd:c25:c25:0:90f0/1282c19:dd:d9:dd:c25:c25:0:90f0
2422c19:dd:d9:dd:c25:c25:0:90f1/1282c19:dd:d9:dd:c25:c25:0:90f1
2432c19:dd:d9:dd:c25:c25:0:90f2/1282c19:dd:d9:dd:c25:c25:0:90f2
2442c19:dd:d9:dd:c25:c25:0:90f3/1282c19:dd:d9:dd:c25:c25:0:90f3
2452c19:dd:d9:dd:c25:c25:0:90f4/1282c19:dd:d9:dd:c25:c25:0:90f4
2462c19:dd:d9:dd:c25:c25:0:90f5/1282c19:dd:d9:dd:c25:c25:0:90f5
2472c19:dd:d9:dd:c25:c25:0:90f6/1282c19:dd:d9:dd:c25:c25:0:90f6
2482c19:dd:d9:dd:c25:c25:0:90f7/1282c19:dd:d9:dd:c25:c25:0:90f7
2492c19:dd:d9:dd:c25:c25:0:90f8/1282c19:dd:d9:dd:c25:c25:0:90f8
2502c19:dd:d9:dd:c25:c25:0:90f9/1282c19:dd:d9:dd:c25:c25:0:90f9
2512c19:dd:d9:dd:c25:c25:0:90fa/1282c19:dd:d9:dd:c25:c25:0:90fa
2522c19:dd:d9:dd:c25:c25:0:90fb/1282c19:dd:d9:dd:c25:c25:0:90fb
2532c19:dd:d9:dd:c25:c25:0:90fc/1282c19:dd:d9:dd:c25:c25:0:90fc
2542c19:dd:d9:dd:c25:c25:0:90fd/1282c19:dd:d9:dd:c25:c25:0:90fd
2552c19:dd:d9:dd:c25:c25:0:90fe/1282c19:dd:d9:dd:c25:c25:0:90fe
2562c19:dd:d9:dd:c25:c25:0:90ff/1282c19:dd:d9:dd:c25:c25:0:90ff

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.