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:a002:8000/116
First address
2c19:dd:d9:dd:c25:c25:a002:8000
Last address
2c19:dd:d9:dd:c25:c25:a002:8fff
Addresses
4,096
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:a002:8000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
8.2.0.0.a.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:a002:8000/116 makes 4,096 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:a002:8000/1282c19:dd:d9:dd:c25:c25:a002:8000
22c19:dd:d9:dd:c25:c25:a002:8001/1282c19:dd:d9:dd:c25:c25:a002:8001
32c19:dd:d9:dd:c25:c25:a002:8002/1282c19:dd:d9:dd:c25:c25:a002:8002
42c19:dd:d9:dd:c25:c25:a002:8003/1282c19:dd:d9:dd:c25:c25:a002:8003
52c19:dd:d9:dd:c25:c25:a002:8004/1282c19:dd:d9:dd:c25:c25:a002:8004
62c19:dd:d9:dd:c25:c25:a002:8005/1282c19:dd:d9:dd:c25:c25:a002:8005
72c19:dd:d9:dd:c25:c25:a002:8006/1282c19:dd:d9:dd:c25:c25:a002:8006
82c19:dd:d9:dd:c25:c25:a002:8007/1282c19:dd:d9:dd:c25:c25:a002:8007
92c19:dd:d9:dd:c25:c25:a002:8008/1282c19:dd:d9:dd:c25:c25:a002:8008
102c19:dd:d9:dd:c25:c25:a002:8009/1282c19:dd:d9:dd:c25:c25:a002:8009
112c19:dd:d9:dd:c25:c25:a002:800a/1282c19:dd:d9:dd:c25:c25:a002:800a
122c19:dd:d9:dd:c25:c25:a002:800b/1282c19:dd:d9:dd:c25:c25:a002:800b
132c19:dd:d9:dd:c25:c25:a002:800c/1282c19:dd:d9:dd:c25:c25:a002:800c
142c19:dd:d9:dd:c25:c25:a002:800d/1282c19:dd:d9:dd:c25:c25:a002:800d
152c19:dd:d9:dd:c25:c25:a002:800e/1282c19:dd:d9:dd:c25:c25:a002:800e
162c19:dd:d9:dd:c25:c25:a002:800f/1282c19:dd:d9:dd:c25:c25:a002:800f
172c19:dd:d9:dd:c25:c25:a002:8010/1282c19:dd:d9:dd:c25:c25:a002:8010
182c19:dd:d9:dd:c25:c25:a002:8011/1282c19:dd:d9:dd:c25:c25:a002:8011
192c19:dd:d9:dd:c25:c25:a002:8012/1282c19:dd:d9:dd:c25:c25:a002:8012
202c19:dd:d9:dd:c25:c25:a002:8013/1282c19:dd:d9:dd:c25:c25:a002:8013
212c19:dd:d9:dd:c25:c25:a002:8014/1282c19:dd:d9:dd:c25:c25:a002:8014
222c19:dd:d9:dd:c25:c25:a002:8015/1282c19:dd:d9:dd:c25:c25:a002:8015
232c19:dd:d9:dd:c25:c25:a002:8016/1282c19:dd:d9:dd:c25:c25:a002:8016
242c19:dd:d9:dd:c25:c25:a002:8017/1282c19:dd:d9:dd:c25:c25:a002:8017
252c19:dd:d9:dd:c25:c25:a002:8018/1282c19:dd:d9:dd:c25:c25:a002:8018
262c19:dd:d9:dd:c25:c25:a002:8019/1282c19:dd:d9:dd:c25:c25:a002:8019
272c19:dd:d9:dd:c25:c25:a002:801a/1282c19:dd:d9:dd:c25:c25:a002:801a
282c19:dd:d9:dd:c25:c25:a002:801b/1282c19:dd:d9:dd:c25:c25:a002:801b
292c19:dd:d9:dd:c25:c25:a002:801c/1282c19:dd:d9:dd:c25:c25:a002:801c
302c19:dd:d9:dd:c25:c25:a002:801d/1282c19:dd:d9:dd:c25:c25:a002:801d
312c19:dd:d9:dd:c25:c25:a002:801e/1282c19:dd:d9:dd:c25:c25:a002:801e
322c19:dd:d9:dd:c25:c25:a002:801f/1282c19:dd:d9:dd:c25:c25:a002:801f
332c19:dd:d9:dd:c25:c25:a002:8020/1282c19:dd:d9:dd:c25:c25:a002:8020
342c19:dd:d9:dd:c25:c25:a002:8021/1282c19:dd:d9:dd:c25:c25:a002:8021
352c19:dd:d9:dd:c25:c25:a002:8022/1282c19:dd:d9:dd:c25:c25:a002:8022
362c19:dd:d9:dd:c25:c25:a002:8023/1282c19:dd:d9:dd:c25:c25:a002:8023
372c19:dd:d9:dd:c25:c25:a002:8024/1282c19:dd:d9:dd:c25:c25:a002:8024
382c19:dd:d9:dd:c25:c25:a002:8025/1282c19:dd:d9:dd:c25:c25:a002:8025
392c19:dd:d9:dd:c25:c25:a002:8026/1282c19:dd:d9:dd:c25:c25:a002:8026
402c19:dd:d9:dd:c25:c25:a002:8027/1282c19:dd:d9:dd:c25:c25:a002:8027
412c19:dd:d9:dd:c25:c25:a002:8028/1282c19:dd:d9:dd:c25:c25:a002:8028
422c19:dd:d9:dd:c25:c25:a002:8029/1282c19:dd:d9:dd:c25:c25:a002:8029
432c19:dd:d9:dd:c25:c25:a002:802a/1282c19:dd:d9:dd:c25:c25:a002:802a
442c19:dd:d9:dd:c25:c25:a002:802b/1282c19:dd:d9:dd:c25:c25:a002:802b
452c19:dd:d9:dd:c25:c25:a002:802c/1282c19:dd:d9:dd:c25:c25:a002:802c
462c19:dd:d9:dd:c25:c25:a002:802d/1282c19:dd:d9:dd:c25:c25:a002:802d
472c19:dd:d9:dd:c25:c25:a002:802e/1282c19:dd:d9:dd:c25:c25:a002:802e
482c19:dd:d9:dd:c25:c25:a002:802f/1282c19:dd:d9:dd:c25:c25:a002:802f
492c19:dd:d9:dd:c25:c25:a002:8030/1282c19:dd:d9:dd:c25:c25:a002:8030
502c19:dd:d9:dd:c25:c25:a002:8031/1282c19:dd:d9:dd:c25:c25:a002:8031
512c19:dd:d9:dd:c25:c25:a002:8032/1282c19:dd:d9:dd:c25:c25:a002:8032
522c19:dd:d9:dd:c25:c25:a002:8033/1282c19:dd:d9:dd:c25:c25:a002:8033
532c19:dd:d9:dd:c25:c25:a002:8034/1282c19:dd:d9:dd:c25:c25:a002:8034
542c19:dd:d9:dd:c25:c25:a002:8035/1282c19:dd:d9:dd:c25:c25:a002:8035
552c19:dd:d9:dd:c25:c25:a002:8036/1282c19:dd:d9:dd:c25:c25:a002:8036
562c19:dd:d9:dd:c25:c25:a002:8037/1282c19:dd:d9:dd:c25:c25:a002:8037
572c19:dd:d9:dd:c25:c25:a002:8038/1282c19:dd:d9:dd:c25:c25:a002:8038
582c19:dd:d9:dd:c25:c25:a002:8039/1282c19:dd:d9:dd:c25:c25:a002:8039
592c19:dd:d9:dd:c25:c25:a002:803a/1282c19:dd:d9:dd:c25:c25:a002:803a
602c19:dd:d9:dd:c25:c25:a002:803b/1282c19:dd:d9:dd:c25:c25:a002:803b
612c19:dd:d9:dd:c25:c25:a002:803c/1282c19:dd:d9:dd:c25:c25:a002:803c
622c19:dd:d9:dd:c25:c25:a002:803d/1282c19:dd:d9:dd:c25:c25:a002:803d
632c19:dd:d9:dd:c25:c25:a002:803e/1282c19:dd:d9:dd:c25:c25:a002:803e
642c19:dd:d9:dd:c25:c25:a002:803f/1282c19:dd:d9:dd:c25:c25:a002:803f
652c19:dd:d9:dd:c25:c25:a002:8040/1282c19:dd:d9:dd:c25:c25:a002:8040
662c19:dd:d9:dd:c25:c25:a002:8041/1282c19:dd:d9:dd:c25:c25:a002:8041
672c19:dd:d9:dd:c25:c25:a002:8042/1282c19:dd:d9:dd:c25:c25:a002:8042
682c19:dd:d9:dd:c25:c25:a002:8043/1282c19:dd:d9:dd:c25:c25:a002:8043
692c19:dd:d9:dd:c25:c25:a002:8044/1282c19:dd:d9:dd:c25:c25:a002:8044
702c19:dd:d9:dd:c25:c25:a002:8045/1282c19:dd:d9:dd:c25:c25:a002:8045
712c19:dd:d9:dd:c25:c25:a002:8046/1282c19:dd:d9:dd:c25:c25:a002:8046
722c19:dd:d9:dd:c25:c25:a002:8047/1282c19:dd:d9:dd:c25:c25:a002:8047
732c19:dd:d9:dd:c25:c25:a002:8048/1282c19:dd:d9:dd:c25:c25:a002:8048
742c19:dd:d9:dd:c25:c25:a002:8049/1282c19:dd:d9:dd:c25:c25:a002:8049
752c19:dd:d9:dd:c25:c25:a002:804a/1282c19:dd:d9:dd:c25:c25:a002:804a
762c19:dd:d9:dd:c25:c25:a002:804b/1282c19:dd:d9:dd:c25:c25:a002:804b
772c19:dd:d9:dd:c25:c25:a002:804c/1282c19:dd:d9:dd:c25:c25:a002:804c
782c19:dd:d9:dd:c25:c25:a002:804d/1282c19:dd:d9:dd:c25:c25:a002:804d
792c19:dd:d9:dd:c25:c25:a002:804e/1282c19:dd:d9:dd:c25:c25:a002:804e
802c19:dd:d9:dd:c25:c25:a002:804f/1282c19:dd:d9:dd:c25:c25:a002:804f
812c19:dd:d9:dd:c25:c25:a002:8050/1282c19:dd:d9:dd:c25:c25:a002:8050
822c19:dd:d9:dd:c25:c25:a002:8051/1282c19:dd:d9:dd:c25:c25:a002:8051
832c19:dd:d9:dd:c25:c25:a002:8052/1282c19:dd:d9:dd:c25:c25:a002:8052
842c19:dd:d9:dd:c25:c25:a002:8053/1282c19:dd:d9:dd:c25:c25:a002:8053
852c19:dd:d9:dd:c25:c25:a002:8054/1282c19:dd:d9:dd:c25:c25:a002:8054
862c19:dd:d9:dd:c25:c25:a002:8055/1282c19:dd:d9:dd:c25:c25:a002:8055
872c19:dd:d9:dd:c25:c25:a002:8056/1282c19:dd:d9:dd:c25:c25:a002:8056
882c19:dd:d9:dd:c25:c25:a002:8057/1282c19:dd:d9:dd:c25:c25:a002:8057
892c19:dd:d9:dd:c25:c25:a002:8058/1282c19:dd:d9:dd:c25:c25:a002:8058
902c19:dd:d9:dd:c25:c25:a002:8059/1282c19:dd:d9:dd:c25:c25:a002:8059
912c19:dd:d9:dd:c25:c25:a002:805a/1282c19:dd:d9:dd:c25:c25:a002:805a
922c19:dd:d9:dd:c25:c25:a002:805b/1282c19:dd:d9:dd:c25:c25:a002:805b
932c19:dd:d9:dd:c25:c25:a002:805c/1282c19:dd:d9:dd:c25:c25:a002:805c
942c19:dd:d9:dd:c25:c25:a002:805d/1282c19:dd:d9:dd:c25:c25:a002:805d
952c19:dd:d9:dd:c25:c25:a002:805e/1282c19:dd:d9:dd:c25:c25:a002:805e
962c19:dd:d9:dd:c25:c25:a002:805f/1282c19:dd:d9:dd:c25:c25:a002:805f
972c19:dd:d9:dd:c25:c25:a002:8060/1282c19:dd:d9:dd:c25:c25:a002:8060
982c19:dd:d9:dd:c25:c25:a002:8061/1282c19:dd:d9:dd:c25:c25:a002:8061
992c19:dd:d9:dd:c25:c25:a002:8062/1282c19:dd:d9:dd:c25:c25:a002:8062
1002c19:dd:d9:dd:c25:c25:a002:8063/1282c19:dd:d9:dd:c25:c25:a002:8063
1012c19:dd:d9:dd:c25:c25:a002:8064/1282c19:dd:d9:dd:c25:c25:a002:8064
1022c19:dd:d9:dd:c25:c25:a002:8065/1282c19:dd:d9:dd:c25:c25:a002:8065
1032c19:dd:d9:dd:c25:c25:a002:8066/1282c19:dd:d9:dd:c25:c25:a002:8066
1042c19:dd:d9:dd:c25:c25:a002:8067/1282c19:dd:d9:dd:c25:c25:a002:8067
1052c19:dd:d9:dd:c25:c25:a002:8068/1282c19:dd:d9:dd:c25:c25:a002:8068
1062c19:dd:d9:dd:c25:c25:a002:8069/1282c19:dd:d9:dd:c25:c25:a002:8069
1072c19:dd:d9:dd:c25:c25:a002:806a/1282c19:dd:d9:dd:c25:c25:a002:806a
1082c19:dd:d9:dd:c25:c25:a002:806b/1282c19:dd:d9:dd:c25:c25:a002:806b
1092c19:dd:d9:dd:c25:c25:a002:806c/1282c19:dd:d9:dd:c25:c25:a002:806c
1102c19:dd:d9:dd:c25:c25:a002:806d/1282c19:dd:d9:dd:c25:c25:a002:806d
1112c19:dd:d9:dd:c25:c25:a002:806e/1282c19:dd:d9:dd:c25:c25:a002:806e
1122c19:dd:d9:dd:c25:c25:a002:806f/1282c19:dd:d9:dd:c25:c25:a002:806f
1132c19:dd:d9:dd:c25:c25:a002:8070/1282c19:dd:d9:dd:c25:c25:a002:8070
1142c19:dd:d9:dd:c25:c25:a002:8071/1282c19:dd:d9:dd:c25:c25:a002:8071
1152c19:dd:d9:dd:c25:c25:a002:8072/1282c19:dd:d9:dd:c25:c25:a002:8072
1162c19:dd:d9:dd:c25:c25:a002:8073/1282c19:dd:d9:dd:c25:c25:a002:8073
1172c19:dd:d9:dd:c25:c25:a002:8074/1282c19:dd:d9:dd:c25:c25:a002:8074
1182c19:dd:d9:dd:c25:c25:a002:8075/1282c19:dd:d9:dd:c25:c25:a002:8075
1192c19:dd:d9:dd:c25:c25:a002:8076/1282c19:dd:d9:dd:c25:c25:a002:8076
1202c19:dd:d9:dd:c25:c25:a002:8077/1282c19:dd:d9:dd:c25:c25:a002:8077
1212c19:dd:d9:dd:c25:c25:a002:8078/1282c19:dd:d9:dd:c25:c25:a002:8078
1222c19:dd:d9:dd:c25:c25:a002:8079/1282c19:dd:d9:dd:c25:c25:a002:8079
1232c19:dd:d9:dd:c25:c25:a002:807a/1282c19:dd:d9:dd:c25:c25:a002:807a
1242c19:dd:d9:dd:c25:c25:a002:807b/1282c19:dd:d9:dd:c25:c25:a002:807b
1252c19:dd:d9:dd:c25:c25:a002:807c/1282c19:dd:d9:dd:c25:c25:a002:807c
1262c19:dd:d9:dd:c25:c25:a002:807d/1282c19:dd:d9:dd:c25:c25:a002:807d
1272c19:dd:d9:dd:c25:c25:a002:807e/1282c19:dd:d9:dd:c25:c25:a002:807e
1282c19:dd:d9:dd:c25:c25:a002:807f/1282c19:dd:d9:dd:c25:c25:a002:807f
1292c19:dd:d9:dd:c25:c25:a002:8080/1282c19:dd:d9:dd:c25:c25:a002:8080
1302c19:dd:d9:dd:c25:c25:a002:8081/1282c19:dd:d9:dd:c25:c25:a002:8081
1312c19:dd:d9:dd:c25:c25:a002:8082/1282c19:dd:d9:dd:c25:c25:a002:8082
1322c19:dd:d9:dd:c25:c25:a002:8083/1282c19:dd:d9:dd:c25:c25:a002:8083
1332c19:dd:d9:dd:c25:c25:a002:8084/1282c19:dd:d9:dd:c25:c25:a002:8084
1342c19:dd:d9:dd:c25:c25:a002:8085/1282c19:dd:d9:dd:c25:c25:a002:8085
1352c19:dd:d9:dd:c25:c25:a002:8086/1282c19:dd:d9:dd:c25:c25:a002:8086
1362c19:dd:d9:dd:c25:c25:a002:8087/1282c19:dd:d9:dd:c25:c25:a002:8087
1372c19:dd:d9:dd:c25:c25:a002:8088/1282c19:dd:d9:dd:c25:c25:a002:8088
1382c19:dd:d9:dd:c25:c25:a002:8089/1282c19:dd:d9:dd:c25:c25:a002:8089
1392c19:dd:d9:dd:c25:c25:a002:808a/1282c19:dd:d9:dd:c25:c25:a002:808a
1402c19:dd:d9:dd:c25:c25:a002:808b/1282c19:dd:d9:dd:c25:c25:a002:808b
1412c19:dd:d9:dd:c25:c25:a002:808c/1282c19:dd:d9:dd:c25:c25:a002:808c
1422c19:dd:d9:dd:c25:c25:a002:808d/1282c19:dd:d9:dd:c25:c25:a002:808d
1432c19:dd:d9:dd:c25:c25:a002:808e/1282c19:dd:d9:dd:c25:c25:a002:808e
1442c19:dd:d9:dd:c25:c25:a002:808f/1282c19:dd:d9:dd:c25:c25:a002:808f
1452c19:dd:d9:dd:c25:c25:a002:8090/1282c19:dd:d9:dd:c25:c25:a002:8090
1462c19:dd:d9:dd:c25:c25:a002:8091/1282c19:dd:d9:dd:c25:c25:a002:8091
1472c19:dd:d9:dd:c25:c25:a002:8092/1282c19:dd:d9:dd:c25:c25:a002:8092
1482c19:dd:d9:dd:c25:c25:a002:8093/1282c19:dd:d9:dd:c25:c25:a002:8093
1492c19:dd:d9:dd:c25:c25:a002:8094/1282c19:dd:d9:dd:c25:c25:a002:8094
1502c19:dd:d9:dd:c25:c25:a002:8095/1282c19:dd:d9:dd:c25:c25:a002:8095
1512c19:dd:d9:dd:c25:c25:a002:8096/1282c19:dd:d9:dd:c25:c25:a002:8096
1522c19:dd:d9:dd:c25:c25:a002:8097/1282c19:dd:d9:dd:c25:c25:a002:8097
1532c19:dd:d9:dd:c25:c25:a002:8098/1282c19:dd:d9:dd:c25:c25:a002:8098
1542c19:dd:d9:dd:c25:c25:a002:8099/1282c19:dd:d9:dd:c25:c25:a002:8099
1552c19:dd:d9:dd:c25:c25:a002:809a/1282c19:dd:d9:dd:c25:c25:a002:809a
1562c19:dd:d9:dd:c25:c25:a002:809b/1282c19:dd:d9:dd:c25:c25:a002:809b
1572c19:dd:d9:dd:c25:c25:a002:809c/1282c19:dd:d9:dd:c25:c25:a002:809c
1582c19:dd:d9:dd:c25:c25:a002:809d/1282c19:dd:d9:dd:c25:c25:a002:809d
1592c19:dd:d9:dd:c25:c25:a002:809e/1282c19:dd:d9:dd:c25:c25:a002:809e
1602c19:dd:d9:dd:c25:c25:a002:809f/1282c19:dd:d9:dd:c25:c25:a002:809f
1612c19:dd:d9:dd:c25:c25:a002:80a0/1282c19:dd:d9:dd:c25:c25:a002:80a0
1622c19:dd:d9:dd:c25:c25:a002:80a1/1282c19:dd:d9:dd:c25:c25:a002:80a1
1632c19:dd:d9:dd:c25:c25:a002:80a2/1282c19:dd:d9:dd:c25:c25:a002:80a2
1642c19:dd:d9:dd:c25:c25:a002:80a3/1282c19:dd:d9:dd:c25:c25:a002:80a3
1652c19:dd:d9:dd:c25:c25:a002:80a4/1282c19:dd:d9:dd:c25:c25:a002:80a4
1662c19:dd:d9:dd:c25:c25:a002:80a5/1282c19:dd:d9:dd:c25:c25:a002:80a5
1672c19:dd:d9:dd:c25:c25:a002:80a6/1282c19:dd:d9:dd:c25:c25:a002:80a6
1682c19:dd:d9:dd:c25:c25:a002:80a7/1282c19:dd:d9:dd:c25:c25:a002:80a7
1692c19:dd:d9:dd:c25:c25:a002:80a8/1282c19:dd:d9:dd:c25:c25:a002:80a8
1702c19:dd:d9:dd:c25:c25:a002:80a9/1282c19:dd:d9:dd:c25:c25:a002:80a9
1712c19:dd:d9:dd:c25:c25:a002:80aa/1282c19:dd:d9:dd:c25:c25:a002:80aa
1722c19:dd:d9:dd:c25:c25:a002:80ab/1282c19:dd:d9:dd:c25:c25:a002:80ab
1732c19:dd:d9:dd:c25:c25:a002:80ac/1282c19:dd:d9:dd:c25:c25:a002:80ac
1742c19:dd:d9:dd:c25:c25:a002:80ad/1282c19:dd:d9:dd:c25:c25:a002:80ad
1752c19:dd:d9:dd:c25:c25:a002:80ae/1282c19:dd:d9:dd:c25:c25:a002:80ae
1762c19:dd:d9:dd:c25:c25:a002:80af/1282c19:dd:d9:dd:c25:c25:a002:80af
1772c19:dd:d9:dd:c25:c25:a002:80b0/1282c19:dd:d9:dd:c25:c25:a002:80b0
1782c19:dd:d9:dd:c25:c25:a002:80b1/1282c19:dd:d9:dd:c25:c25:a002:80b1
1792c19:dd:d9:dd:c25:c25:a002:80b2/1282c19:dd:d9:dd:c25:c25:a002:80b2
1802c19:dd:d9:dd:c25:c25:a002:80b3/1282c19:dd:d9:dd:c25:c25:a002:80b3
1812c19:dd:d9:dd:c25:c25:a002:80b4/1282c19:dd:d9:dd:c25:c25:a002:80b4
1822c19:dd:d9:dd:c25:c25:a002:80b5/1282c19:dd:d9:dd:c25:c25:a002:80b5
1832c19:dd:d9:dd:c25:c25:a002:80b6/1282c19:dd:d9:dd:c25:c25:a002:80b6
1842c19:dd:d9:dd:c25:c25:a002:80b7/1282c19:dd:d9:dd:c25:c25:a002:80b7
1852c19:dd:d9:dd:c25:c25:a002:80b8/1282c19:dd:d9:dd:c25:c25:a002:80b8
1862c19:dd:d9:dd:c25:c25:a002:80b9/1282c19:dd:d9:dd:c25:c25:a002:80b9
1872c19:dd:d9:dd:c25:c25:a002:80ba/1282c19:dd:d9:dd:c25:c25:a002:80ba
1882c19:dd:d9:dd:c25:c25:a002:80bb/1282c19:dd:d9:dd:c25:c25:a002:80bb
1892c19:dd:d9:dd:c25:c25:a002:80bc/1282c19:dd:d9:dd:c25:c25:a002:80bc
1902c19:dd:d9:dd:c25:c25:a002:80bd/1282c19:dd:d9:dd:c25:c25:a002:80bd
1912c19:dd:d9:dd:c25:c25:a002:80be/1282c19:dd:d9:dd:c25:c25:a002:80be
1922c19:dd:d9:dd:c25:c25:a002:80bf/1282c19:dd:d9:dd:c25:c25:a002:80bf
1932c19:dd:d9:dd:c25:c25:a002:80c0/1282c19:dd:d9:dd:c25:c25:a002:80c0
1942c19:dd:d9:dd:c25:c25:a002:80c1/1282c19:dd:d9:dd:c25:c25:a002:80c1
1952c19:dd:d9:dd:c25:c25:a002:80c2/1282c19:dd:d9:dd:c25:c25:a002:80c2
1962c19:dd:d9:dd:c25:c25:a002:80c3/1282c19:dd:d9:dd:c25:c25:a002:80c3
1972c19:dd:d9:dd:c25:c25:a002:80c4/1282c19:dd:d9:dd:c25:c25:a002:80c4
1982c19:dd:d9:dd:c25:c25:a002:80c5/1282c19:dd:d9:dd:c25:c25:a002:80c5
1992c19:dd:d9:dd:c25:c25:a002:80c6/1282c19:dd:d9:dd:c25:c25:a002:80c6
2002c19:dd:d9:dd:c25:c25:a002:80c7/1282c19:dd:d9:dd:c25:c25:a002:80c7
2012c19:dd:d9:dd:c25:c25:a002:80c8/1282c19:dd:d9:dd:c25:c25:a002:80c8
2022c19:dd:d9:dd:c25:c25:a002:80c9/1282c19:dd:d9:dd:c25:c25:a002:80c9
2032c19:dd:d9:dd:c25:c25:a002:80ca/1282c19:dd:d9:dd:c25:c25:a002:80ca
2042c19:dd:d9:dd:c25:c25:a002:80cb/1282c19:dd:d9:dd:c25:c25:a002:80cb
2052c19:dd:d9:dd:c25:c25:a002:80cc/1282c19:dd:d9:dd:c25:c25:a002:80cc
2062c19:dd:d9:dd:c25:c25:a002:80cd/1282c19:dd:d9:dd:c25:c25:a002:80cd
2072c19:dd:d9:dd:c25:c25:a002:80ce/1282c19:dd:d9:dd:c25:c25:a002:80ce
2082c19:dd:d9:dd:c25:c25:a002:80cf/1282c19:dd:d9:dd:c25:c25:a002:80cf
2092c19:dd:d9:dd:c25:c25:a002:80d0/1282c19:dd:d9:dd:c25:c25:a002:80d0
2102c19:dd:d9:dd:c25:c25:a002:80d1/1282c19:dd:d9:dd:c25:c25:a002:80d1
2112c19:dd:d9:dd:c25:c25:a002:80d2/1282c19:dd:d9:dd:c25:c25:a002:80d2
2122c19:dd:d9:dd:c25:c25:a002:80d3/1282c19:dd:d9:dd:c25:c25:a002:80d3
2132c19:dd:d9:dd:c25:c25:a002:80d4/1282c19:dd:d9:dd:c25:c25:a002:80d4
2142c19:dd:d9:dd:c25:c25:a002:80d5/1282c19:dd:d9:dd:c25:c25:a002:80d5
2152c19:dd:d9:dd:c25:c25:a002:80d6/1282c19:dd:d9:dd:c25:c25:a002:80d6
2162c19:dd:d9:dd:c25:c25:a002:80d7/1282c19:dd:d9:dd:c25:c25:a002:80d7
2172c19:dd:d9:dd:c25:c25:a002:80d8/1282c19:dd:d9:dd:c25:c25:a002:80d8
2182c19:dd:d9:dd:c25:c25:a002:80d9/1282c19:dd:d9:dd:c25:c25:a002:80d9
2192c19:dd:d9:dd:c25:c25:a002:80da/1282c19:dd:d9:dd:c25:c25:a002:80da
2202c19:dd:d9:dd:c25:c25:a002:80db/1282c19:dd:d9:dd:c25:c25:a002:80db
2212c19:dd:d9:dd:c25:c25:a002:80dc/1282c19:dd:d9:dd:c25:c25:a002:80dc
2222c19:dd:d9:dd:c25:c25:a002:80dd/1282c19:dd:d9:dd:c25:c25:a002:80dd
2232c19:dd:d9:dd:c25:c25:a002:80de/1282c19:dd:d9:dd:c25:c25:a002:80de
2242c19:dd:d9:dd:c25:c25:a002:80df/1282c19:dd:d9:dd:c25:c25:a002:80df
2252c19:dd:d9:dd:c25:c25:a002:80e0/1282c19:dd:d9:dd:c25:c25:a002:80e0
2262c19:dd:d9:dd:c25:c25:a002:80e1/1282c19:dd:d9:dd:c25:c25:a002:80e1
2272c19:dd:d9:dd:c25:c25:a002:80e2/1282c19:dd:d9:dd:c25:c25:a002:80e2
2282c19:dd:d9:dd:c25:c25:a002:80e3/1282c19:dd:d9:dd:c25:c25:a002:80e3
2292c19:dd:d9:dd:c25:c25:a002:80e4/1282c19:dd:d9:dd:c25:c25:a002:80e4
2302c19:dd:d9:dd:c25:c25:a002:80e5/1282c19:dd:d9:dd:c25:c25:a002:80e5
2312c19:dd:d9:dd:c25:c25:a002:80e6/1282c19:dd:d9:dd:c25:c25:a002:80e6
2322c19:dd:d9:dd:c25:c25:a002:80e7/1282c19:dd:d9:dd:c25:c25:a002:80e7
2332c19:dd:d9:dd:c25:c25:a002:80e8/1282c19:dd:d9:dd:c25:c25:a002:80e8
2342c19:dd:d9:dd:c25:c25:a002:80e9/1282c19:dd:d9:dd:c25:c25:a002:80e9
2352c19:dd:d9:dd:c25:c25:a002:80ea/1282c19:dd:d9:dd:c25:c25:a002:80ea
2362c19:dd:d9:dd:c25:c25:a002:80eb/1282c19:dd:d9:dd:c25:c25:a002:80eb
2372c19:dd:d9:dd:c25:c25:a002:80ec/1282c19:dd:d9:dd:c25:c25:a002:80ec
2382c19:dd:d9:dd:c25:c25:a002:80ed/1282c19:dd:d9:dd:c25:c25:a002:80ed
2392c19:dd:d9:dd:c25:c25:a002:80ee/1282c19:dd:d9:dd:c25:c25:a002:80ee
2402c19:dd:d9:dd:c25:c25:a002:80ef/1282c19:dd:d9:dd:c25:c25:a002:80ef
2412c19:dd:d9:dd:c25:c25:a002:80f0/1282c19:dd:d9:dd:c25:c25:a002:80f0
2422c19:dd:d9:dd:c25:c25:a002:80f1/1282c19:dd:d9:dd:c25:c25:a002:80f1
2432c19:dd:d9:dd:c25:c25:a002:80f2/1282c19:dd:d9:dd:c25:c25:a002:80f2
2442c19:dd:d9:dd:c25:c25:a002:80f3/1282c19:dd:d9:dd:c25:c25:a002:80f3
2452c19:dd:d9:dd:c25:c25:a002:80f4/1282c19:dd:d9:dd:c25:c25:a002:80f4
2462c19:dd:d9:dd:c25:c25:a002:80f5/1282c19:dd:d9:dd:c25:c25:a002:80f5
2472c19:dd:d9:dd:c25:c25:a002:80f6/1282c19:dd:d9:dd:c25:c25:a002:80f6
2482c19:dd:d9:dd:c25:c25:a002:80f7/1282c19:dd:d9:dd:c25:c25:a002:80f7
2492c19:dd:d9:dd:c25:c25:a002:80f8/1282c19:dd:d9:dd:c25:c25:a002:80f8
2502c19:dd:d9:dd:c25:c25:a002:80f9/1282c19:dd:d9:dd:c25:c25:a002:80f9
2512c19:dd:d9:dd:c25:c25:a002:80fa/1282c19:dd:d9:dd:c25:c25:a002:80fa
2522c19:dd:d9:dd:c25:c25:a002:80fb/1282c19:dd:d9:dd:c25:c25:a002:80fb
2532c19:dd:d9:dd:c25:c25:a002:80fc/1282c19:dd:d9:dd:c25:c25:a002:80fc
2542c19:dd:d9:dd:c25:c25:a002:80fd/1282c19:dd:d9:dd:c25:c25:a002:80fd
2552c19:dd:d9:dd:c25:c25:a002:80fe/1282c19:dd:d9:dd:c25:c25:a002:80fe
2562c19:dd:d9:dd:c25:c25:a002:80ff/1282c19:dd:d9:dd:c25:c25:a002:80ff

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.