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

Subnets
#SubnetLast address
12c19:dd:ec00:c25:c25e:dd:ddda:2000/1282c19:dd:ec00:c25:c25e:dd:ddda:2000
22c19:dd:ec00:c25:c25e:dd:ddda:2001/1282c19:dd:ec00:c25:c25e:dd:ddda:2001
32c19:dd:ec00:c25:c25e:dd:ddda:2002/1282c19:dd:ec00:c25:c25e:dd:ddda:2002
42c19:dd:ec00:c25:c25e:dd:ddda:2003/1282c19:dd:ec00:c25:c25e:dd:ddda:2003
52c19:dd:ec00:c25:c25e:dd:ddda:2004/1282c19:dd:ec00:c25:c25e:dd:ddda:2004
62c19:dd:ec00:c25:c25e:dd:ddda:2005/1282c19:dd:ec00:c25:c25e:dd:ddda:2005
72c19:dd:ec00:c25:c25e:dd:ddda:2006/1282c19:dd:ec00:c25:c25e:dd:ddda:2006
82c19:dd:ec00:c25:c25e:dd:ddda:2007/1282c19:dd:ec00:c25:c25e:dd:ddda:2007
92c19:dd:ec00:c25:c25e:dd:ddda:2008/1282c19:dd:ec00:c25:c25e:dd:ddda:2008
102c19:dd:ec00:c25:c25e:dd:ddda:2009/1282c19:dd:ec00:c25:c25e:dd:ddda:2009
112c19:dd:ec00:c25:c25e:dd:ddda:200a/1282c19:dd:ec00:c25:c25e:dd:ddda:200a
122c19:dd:ec00:c25:c25e:dd:ddda:200b/1282c19:dd:ec00:c25:c25e:dd:ddda:200b
132c19:dd:ec00:c25:c25e:dd:ddda:200c/1282c19:dd:ec00:c25:c25e:dd:ddda:200c
142c19:dd:ec00:c25:c25e:dd:ddda:200d/1282c19:dd:ec00:c25:c25e:dd:ddda:200d
152c19:dd:ec00:c25:c25e:dd:ddda:200e/1282c19:dd:ec00:c25:c25e:dd:ddda:200e
162c19:dd:ec00:c25:c25e:dd:ddda:200f/1282c19:dd:ec00:c25:c25e:dd:ddda:200f
172c19:dd:ec00:c25:c25e:dd:ddda:2010/1282c19:dd:ec00:c25:c25e:dd:ddda:2010
182c19:dd:ec00:c25:c25e:dd:ddda:2011/1282c19:dd:ec00:c25:c25e:dd:ddda:2011
192c19:dd:ec00:c25:c25e:dd:ddda:2012/1282c19:dd:ec00:c25:c25e:dd:ddda:2012
202c19:dd:ec00:c25:c25e:dd:ddda:2013/1282c19:dd:ec00:c25:c25e:dd:ddda:2013
212c19:dd:ec00:c25:c25e:dd:ddda:2014/1282c19:dd:ec00:c25:c25e:dd:ddda:2014
222c19:dd:ec00:c25:c25e:dd:ddda:2015/1282c19:dd:ec00:c25:c25e:dd:ddda:2015
232c19:dd:ec00:c25:c25e:dd:ddda:2016/1282c19:dd:ec00:c25:c25e:dd:ddda:2016
242c19:dd:ec00:c25:c25e:dd:ddda:2017/1282c19:dd:ec00:c25:c25e:dd:ddda:2017
252c19:dd:ec00:c25:c25e:dd:ddda:2018/1282c19:dd:ec00:c25:c25e:dd:ddda:2018
262c19:dd:ec00:c25:c25e:dd:ddda:2019/1282c19:dd:ec00:c25:c25e:dd:ddda:2019
272c19:dd:ec00:c25:c25e:dd:ddda:201a/1282c19:dd:ec00:c25:c25e:dd:ddda:201a
282c19:dd:ec00:c25:c25e:dd:ddda:201b/1282c19:dd:ec00:c25:c25e:dd:ddda:201b
292c19:dd:ec00:c25:c25e:dd:ddda:201c/1282c19:dd:ec00:c25:c25e:dd:ddda:201c
302c19:dd:ec00:c25:c25e:dd:ddda:201d/1282c19:dd:ec00:c25:c25e:dd:ddda:201d
312c19:dd:ec00:c25:c25e:dd:ddda:201e/1282c19:dd:ec00:c25:c25e:dd:ddda:201e
322c19:dd:ec00:c25:c25e:dd:ddda:201f/1282c19:dd:ec00:c25:c25e:dd:ddda:201f
332c19:dd:ec00:c25:c25e:dd:ddda:2020/1282c19:dd:ec00:c25:c25e:dd:ddda:2020
342c19:dd:ec00:c25:c25e:dd:ddda:2021/1282c19:dd:ec00:c25:c25e:dd:ddda:2021
352c19:dd:ec00:c25:c25e:dd:ddda:2022/1282c19:dd:ec00:c25:c25e:dd:ddda:2022
362c19:dd:ec00:c25:c25e:dd:ddda:2023/1282c19:dd:ec00:c25:c25e:dd:ddda:2023
372c19:dd:ec00:c25:c25e:dd:ddda:2024/1282c19:dd:ec00:c25:c25e:dd:ddda:2024
382c19:dd:ec00:c25:c25e:dd:ddda:2025/1282c19:dd:ec00:c25:c25e:dd:ddda:2025
392c19:dd:ec00:c25:c25e:dd:ddda:2026/1282c19:dd:ec00:c25:c25e:dd:ddda:2026
402c19:dd:ec00:c25:c25e:dd:ddda:2027/1282c19:dd:ec00:c25:c25e:dd:ddda:2027
412c19:dd:ec00:c25:c25e:dd:ddda:2028/1282c19:dd:ec00:c25:c25e:dd:ddda:2028
422c19:dd:ec00:c25:c25e:dd:ddda:2029/1282c19:dd:ec00:c25:c25e:dd:ddda:2029
432c19:dd:ec00:c25:c25e:dd:ddda:202a/1282c19:dd:ec00:c25:c25e:dd:ddda:202a
442c19:dd:ec00:c25:c25e:dd:ddda:202b/1282c19:dd:ec00:c25:c25e:dd:ddda:202b
452c19:dd:ec00:c25:c25e:dd:ddda:202c/1282c19:dd:ec00:c25:c25e:dd:ddda:202c
462c19:dd:ec00:c25:c25e:dd:ddda:202d/1282c19:dd:ec00:c25:c25e:dd:ddda:202d
472c19:dd:ec00:c25:c25e:dd:ddda:202e/1282c19:dd:ec00:c25:c25e:dd:ddda:202e
482c19:dd:ec00:c25:c25e:dd:ddda:202f/1282c19:dd:ec00:c25:c25e:dd:ddda:202f
492c19:dd:ec00:c25:c25e:dd:ddda:2030/1282c19:dd:ec00:c25:c25e:dd:ddda:2030
502c19:dd:ec00:c25:c25e:dd:ddda:2031/1282c19:dd:ec00:c25:c25e:dd:ddda:2031
512c19:dd:ec00:c25:c25e:dd:ddda:2032/1282c19:dd:ec00:c25:c25e:dd:ddda:2032
522c19:dd:ec00:c25:c25e:dd:ddda:2033/1282c19:dd:ec00:c25:c25e:dd:ddda:2033
532c19:dd:ec00:c25:c25e:dd:ddda:2034/1282c19:dd:ec00:c25:c25e:dd:ddda:2034
542c19:dd:ec00:c25:c25e:dd:ddda:2035/1282c19:dd:ec00:c25:c25e:dd:ddda:2035
552c19:dd:ec00:c25:c25e:dd:ddda:2036/1282c19:dd:ec00:c25:c25e:dd:ddda:2036
562c19:dd:ec00:c25:c25e:dd:ddda:2037/1282c19:dd:ec00:c25:c25e:dd:ddda:2037
572c19:dd:ec00:c25:c25e:dd:ddda:2038/1282c19:dd:ec00:c25:c25e:dd:ddda:2038
582c19:dd:ec00:c25:c25e:dd:ddda:2039/1282c19:dd:ec00:c25:c25e:dd:ddda:2039
592c19:dd:ec00:c25:c25e:dd:ddda:203a/1282c19:dd:ec00:c25:c25e:dd:ddda:203a
602c19:dd:ec00:c25:c25e:dd:ddda:203b/1282c19:dd:ec00:c25:c25e:dd:ddda:203b
612c19:dd:ec00:c25:c25e:dd:ddda:203c/1282c19:dd:ec00:c25:c25e:dd:ddda:203c
622c19:dd:ec00:c25:c25e:dd:ddda:203d/1282c19:dd:ec00:c25:c25e:dd:ddda:203d
632c19:dd:ec00:c25:c25e:dd:ddda:203e/1282c19:dd:ec00:c25:c25e:dd:ddda:203e
642c19:dd:ec00:c25:c25e:dd:ddda:203f/1282c19:dd:ec00:c25:c25e:dd:ddda:203f
652c19:dd:ec00:c25:c25e:dd:ddda:2040/1282c19:dd:ec00:c25:c25e:dd:ddda:2040
662c19:dd:ec00:c25:c25e:dd:ddda:2041/1282c19:dd:ec00:c25:c25e:dd:ddda:2041
672c19:dd:ec00:c25:c25e:dd:ddda:2042/1282c19:dd:ec00:c25:c25e:dd:ddda:2042
682c19:dd:ec00:c25:c25e:dd:ddda:2043/1282c19:dd:ec00:c25:c25e:dd:ddda:2043
692c19:dd:ec00:c25:c25e:dd:ddda:2044/1282c19:dd:ec00:c25:c25e:dd:ddda:2044
702c19:dd:ec00:c25:c25e:dd:ddda:2045/1282c19:dd:ec00:c25:c25e:dd:ddda:2045
712c19:dd:ec00:c25:c25e:dd:ddda:2046/1282c19:dd:ec00:c25:c25e:dd:ddda:2046
722c19:dd:ec00:c25:c25e:dd:ddda:2047/1282c19:dd:ec00:c25:c25e:dd:ddda:2047
732c19:dd:ec00:c25:c25e:dd:ddda:2048/1282c19:dd:ec00:c25:c25e:dd:ddda:2048
742c19:dd:ec00:c25:c25e:dd:ddda:2049/1282c19:dd:ec00:c25:c25e:dd:ddda:2049
752c19:dd:ec00:c25:c25e:dd:ddda:204a/1282c19:dd:ec00:c25:c25e:dd:ddda:204a
762c19:dd:ec00:c25:c25e:dd:ddda:204b/1282c19:dd:ec00:c25:c25e:dd:ddda:204b
772c19:dd:ec00:c25:c25e:dd:ddda:204c/1282c19:dd:ec00:c25:c25e:dd:ddda:204c
782c19:dd:ec00:c25:c25e:dd:ddda:204d/1282c19:dd:ec00:c25:c25e:dd:ddda:204d
792c19:dd:ec00:c25:c25e:dd:ddda:204e/1282c19:dd:ec00:c25:c25e:dd:ddda:204e
802c19:dd:ec00:c25:c25e:dd:ddda:204f/1282c19:dd:ec00:c25:c25e:dd:ddda:204f
812c19:dd:ec00:c25:c25e:dd:ddda:2050/1282c19:dd:ec00:c25:c25e:dd:ddda:2050
822c19:dd:ec00:c25:c25e:dd:ddda:2051/1282c19:dd:ec00:c25:c25e:dd:ddda:2051
832c19:dd:ec00:c25:c25e:dd:ddda:2052/1282c19:dd:ec00:c25:c25e:dd:ddda:2052
842c19:dd:ec00:c25:c25e:dd:ddda:2053/1282c19:dd:ec00:c25:c25e:dd:ddda:2053
852c19:dd:ec00:c25:c25e:dd:ddda:2054/1282c19:dd:ec00:c25:c25e:dd:ddda:2054
862c19:dd:ec00:c25:c25e:dd:ddda:2055/1282c19:dd:ec00:c25:c25e:dd:ddda:2055
872c19:dd:ec00:c25:c25e:dd:ddda:2056/1282c19:dd:ec00:c25:c25e:dd:ddda:2056
882c19:dd:ec00:c25:c25e:dd:ddda:2057/1282c19:dd:ec00:c25:c25e:dd:ddda:2057
892c19:dd:ec00:c25:c25e:dd:ddda:2058/1282c19:dd:ec00:c25:c25e:dd:ddda:2058
902c19:dd:ec00:c25:c25e:dd:ddda:2059/1282c19:dd:ec00:c25:c25e:dd:ddda:2059
912c19:dd:ec00:c25:c25e:dd:ddda:205a/1282c19:dd:ec00:c25:c25e:dd:ddda:205a
922c19:dd:ec00:c25:c25e:dd:ddda:205b/1282c19:dd:ec00:c25:c25e:dd:ddda:205b
932c19:dd:ec00:c25:c25e:dd:ddda:205c/1282c19:dd:ec00:c25:c25e:dd:ddda:205c
942c19:dd:ec00:c25:c25e:dd:ddda:205d/1282c19:dd:ec00:c25:c25e:dd:ddda:205d
952c19:dd:ec00:c25:c25e:dd:ddda:205e/1282c19:dd:ec00:c25:c25e:dd:ddda:205e
962c19:dd:ec00:c25:c25e:dd:ddda:205f/1282c19:dd:ec00:c25:c25e:dd:ddda:205f
972c19:dd:ec00:c25:c25e:dd:ddda:2060/1282c19:dd:ec00:c25:c25e:dd:ddda:2060
982c19:dd:ec00:c25:c25e:dd:ddda:2061/1282c19:dd:ec00:c25:c25e:dd:ddda:2061
992c19:dd:ec00:c25:c25e:dd:ddda:2062/1282c19:dd:ec00:c25:c25e:dd:ddda:2062
1002c19:dd:ec00:c25:c25e:dd:ddda:2063/1282c19:dd:ec00:c25:c25e:dd:ddda:2063
1012c19:dd:ec00:c25:c25e:dd:ddda:2064/1282c19:dd:ec00:c25:c25e:dd:ddda:2064
1022c19:dd:ec00:c25:c25e:dd:ddda:2065/1282c19:dd:ec00:c25:c25e:dd:ddda:2065
1032c19:dd:ec00:c25:c25e:dd:ddda:2066/1282c19:dd:ec00:c25:c25e:dd:ddda:2066
1042c19:dd:ec00:c25:c25e:dd:ddda:2067/1282c19:dd:ec00:c25:c25e:dd:ddda:2067
1052c19:dd:ec00:c25:c25e:dd:ddda:2068/1282c19:dd:ec00:c25:c25e:dd:ddda:2068
1062c19:dd:ec00:c25:c25e:dd:ddda:2069/1282c19:dd:ec00:c25:c25e:dd:ddda:2069
1072c19:dd:ec00:c25:c25e:dd:ddda:206a/1282c19:dd:ec00:c25:c25e:dd:ddda:206a
1082c19:dd:ec00:c25:c25e:dd:ddda:206b/1282c19:dd:ec00:c25:c25e:dd:ddda:206b
1092c19:dd:ec00:c25:c25e:dd:ddda:206c/1282c19:dd:ec00:c25:c25e:dd:ddda:206c
1102c19:dd:ec00:c25:c25e:dd:ddda:206d/1282c19:dd:ec00:c25:c25e:dd:ddda:206d
1112c19:dd:ec00:c25:c25e:dd:ddda:206e/1282c19:dd:ec00:c25:c25e:dd:ddda:206e
1122c19:dd:ec00:c25:c25e:dd:ddda:206f/1282c19:dd:ec00:c25:c25e:dd:ddda:206f
1132c19:dd:ec00:c25:c25e:dd:ddda:2070/1282c19:dd:ec00:c25:c25e:dd:ddda:2070
1142c19:dd:ec00:c25:c25e:dd:ddda:2071/1282c19:dd:ec00:c25:c25e:dd:ddda:2071
1152c19:dd:ec00:c25:c25e:dd:ddda:2072/1282c19:dd:ec00:c25:c25e:dd:ddda:2072
1162c19:dd:ec00:c25:c25e:dd:ddda:2073/1282c19:dd:ec00:c25:c25e:dd:ddda:2073
1172c19:dd:ec00:c25:c25e:dd:ddda:2074/1282c19:dd:ec00:c25:c25e:dd:ddda:2074
1182c19:dd:ec00:c25:c25e:dd:ddda:2075/1282c19:dd:ec00:c25:c25e:dd:ddda:2075
1192c19:dd:ec00:c25:c25e:dd:ddda:2076/1282c19:dd:ec00:c25:c25e:dd:ddda:2076
1202c19:dd:ec00:c25:c25e:dd:ddda:2077/1282c19:dd:ec00:c25:c25e:dd:ddda:2077
1212c19:dd:ec00:c25:c25e:dd:ddda:2078/1282c19:dd:ec00:c25:c25e:dd:ddda:2078
1222c19:dd:ec00:c25:c25e:dd:ddda:2079/1282c19:dd:ec00:c25:c25e:dd:ddda:2079
1232c19:dd:ec00:c25:c25e:dd:ddda:207a/1282c19:dd:ec00:c25:c25e:dd:ddda:207a
1242c19:dd:ec00:c25:c25e:dd:ddda:207b/1282c19:dd:ec00:c25:c25e:dd:ddda:207b
1252c19:dd:ec00:c25:c25e:dd:ddda:207c/1282c19:dd:ec00:c25:c25e:dd:ddda:207c
1262c19:dd:ec00:c25:c25e:dd:ddda:207d/1282c19:dd:ec00:c25:c25e:dd:ddda:207d
1272c19:dd:ec00:c25:c25e:dd:ddda:207e/1282c19:dd:ec00:c25:c25e:dd:ddda:207e
1282c19:dd:ec00:c25:c25e:dd:ddda:207f/1282c19:dd:ec00:c25:c25e:dd:ddda:207f
1292c19:dd:ec00:c25:c25e:dd:ddda:2080/1282c19:dd:ec00:c25:c25e:dd:ddda:2080
1302c19:dd:ec00:c25:c25e:dd:ddda:2081/1282c19:dd:ec00:c25:c25e:dd:ddda:2081
1312c19:dd:ec00:c25:c25e:dd:ddda:2082/1282c19:dd:ec00:c25:c25e:dd:ddda:2082
1322c19:dd:ec00:c25:c25e:dd:ddda:2083/1282c19:dd:ec00:c25:c25e:dd:ddda:2083
1332c19:dd:ec00:c25:c25e:dd:ddda:2084/1282c19:dd:ec00:c25:c25e:dd:ddda:2084
1342c19:dd:ec00:c25:c25e:dd:ddda:2085/1282c19:dd:ec00:c25:c25e:dd:ddda:2085
1352c19:dd:ec00:c25:c25e:dd:ddda:2086/1282c19:dd:ec00:c25:c25e:dd:ddda:2086
1362c19:dd:ec00:c25:c25e:dd:ddda:2087/1282c19:dd:ec00:c25:c25e:dd:ddda:2087
1372c19:dd:ec00:c25:c25e:dd:ddda:2088/1282c19:dd:ec00:c25:c25e:dd:ddda:2088
1382c19:dd:ec00:c25:c25e:dd:ddda:2089/1282c19:dd:ec00:c25:c25e:dd:ddda:2089
1392c19:dd:ec00:c25:c25e:dd:ddda:208a/1282c19:dd:ec00:c25:c25e:dd:ddda:208a
1402c19:dd:ec00:c25:c25e:dd:ddda:208b/1282c19:dd:ec00:c25:c25e:dd:ddda:208b
1412c19:dd:ec00:c25:c25e:dd:ddda:208c/1282c19:dd:ec00:c25:c25e:dd:ddda:208c
1422c19:dd:ec00:c25:c25e:dd:ddda:208d/1282c19:dd:ec00:c25:c25e:dd:ddda:208d
1432c19:dd:ec00:c25:c25e:dd:ddda:208e/1282c19:dd:ec00:c25:c25e:dd:ddda:208e
1442c19:dd:ec00:c25:c25e:dd:ddda:208f/1282c19:dd:ec00:c25:c25e:dd:ddda:208f
1452c19:dd:ec00:c25:c25e:dd:ddda:2090/1282c19:dd:ec00:c25:c25e:dd:ddda:2090
1462c19:dd:ec00:c25:c25e:dd:ddda:2091/1282c19:dd:ec00:c25:c25e:dd:ddda:2091
1472c19:dd:ec00:c25:c25e:dd:ddda:2092/1282c19:dd:ec00:c25:c25e:dd:ddda:2092
1482c19:dd:ec00:c25:c25e:dd:ddda:2093/1282c19:dd:ec00:c25:c25e:dd:ddda:2093
1492c19:dd:ec00:c25:c25e:dd:ddda:2094/1282c19:dd:ec00:c25:c25e:dd:ddda:2094
1502c19:dd:ec00:c25:c25e:dd:ddda:2095/1282c19:dd:ec00:c25:c25e:dd:ddda:2095
1512c19:dd:ec00:c25:c25e:dd:ddda:2096/1282c19:dd:ec00:c25:c25e:dd:ddda:2096
1522c19:dd:ec00:c25:c25e:dd:ddda:2097/1282c19:dd:ec00:c25:c25e:dd:ddda:2097
1532c19:dd:ec00:c25:c25e:dd:ddda:2098/1282c19:dd:ec00:c25:c25e:dd:ddda:2098
1542c19:dd:ec00:c25:c25e:dd:ddda:2099/1282c19:dd:ec00:c25:c25e:dd:ddda:2099
1552c19:dd:ec00:c25:c25e:dd:ddda:209a/1282c19:dd:ec00:c25:c25e:dd:ddda:209a
1562c19:dd:ec00:c25:c25e:dd:ddda:209b/1282c19:dd:ec00:c25:c25e:dd:ddda:209b
1572c19:dd:ec00:c25:c25e:dd:ddda:209c/1282c19:dd:ec00:c25:c25e:dd:ddda:209c
1582c19:dd:ec00:c25:c25e:dd:ddda:209d/1282c19:dd:ec00:c25:c25e:dd:ddda:209d
1592c19:dd:ec00:c25:c25e:dd:ddda:209e/1282c19:dd:ec00:c25:c25e:dd:ddda:209e
1602c19:dd:ec00:c25:c25e:dd:ddda:209f/1282c19:dd:ec00:c25:c25e:dd:ddda:209f
1612c19:dd:ec00:c25:c25e:dd:ddda:20a0/1282c19:dd:ec00:c25:c25e:dd:ddda:20a0
1622c19:dd:ec00:c25:c25e:dd:ddda:20a1/1282c19:dd:ec00:c25:c25e:dd:ddda:20a1
1632c19:dd:ec00:c25:c25e:dd:ddda:20a2/1282c19:dd:ec00:c25:c25e:dd:ddda:20a2
1642c19:dd:ec00:c25:c25e:dd:ddda:20a3/1282c19:dd:ec00:c25:c25e:dd:ddda:20a3
1652c19:dd:ec00:c25:c25e:dd:ddda:20a4/1282c19:dd:ec00:c25:c25e:dd:ddda:20a4
1662c19:dd:ec00:c25:c25e:dd:ddda:20a5/1282c19:dd:ec00:c25:c25e:dd:ddda:20a5
1672c19:dd:ec00:c25:c25e:dd:ddda:20a6/1282c19:dd:ec00:c25:c25e:dd:ddda:20a6
1682c19:dd:ec00:c25:c25e:dd:ddda:20a7/1282c19:dd:ec00:c25:c25e:dd:ddda:20a7
1692c19:dd:ec00:c25:c25e:dd:ddda:20a8/1282c19:dd:ec00:c25:c25e:dd:ddda:20a8
1702c19:dd:ec00:c25:c25e:dd:ddda:20a9/1282c19:dd:ec00:c25:c25e:dd:ddda:20a9
1712c19:dd:ec00:c25:c25e:dd:ddda:20aa/1282c19:dd:ec00:c25:c25e:dd:ddda:20aa
1722c19:dd:ec00:c25:c25e:dd:ddda:20ab/1282c19:dd:ec00:c25:c25e:dd:ddda:20ab
1732c19:dd:ec00:c25:c25e:dd:ddda:20ac/1282c19:dd:ec00:c25:c25e:dd:ddda:20ac
1742c19:dd:ec00:c25:c25e:dd:ddda:20ad/1282c19:dd:ec00:c25:c25e:dd:ddda:20ad
1752c19:dd:ec00:c25:c25e:dd:ddda:20ae/1282c19:dd:ec00:c25:c25e:dd:ddda:20ae
1762c19:dd:ec00:c25:c25e:dd:ddda:20af/1282c19:dd:ec00:c25:c25e:dd:ddda:20af
1772c19:dd:ec00:c25:c25e:dd:ddda:20b0/1282c19:dd:ec00:c25:c25e:dd:ddda:20b0
1782c19:dd:ec00:c25:c25e:dd:ddda:20b1/1282c19:dd:ec00:c25:c25e:dd:ddda:20b1
1792c19:dd:ec00:c25:c25e:dd:ddda:20b2/1282c19:dd:ec00:c25:c25e:dd:ddda:20b2
1802c19:dd:ec00:c25:c25e:dd:ddda:20b3/1282c19:dd:ec00:c25:c25e:dd:ddda:20b3
1812c19:dd:ec00:c25:c25e:dd:ddda:20b4/1282c19:dd:ec00:c25:c25e:dd:ddda:20b4
1822c19:dd:ec00:c25:c25e:dd:ddda:20b5/1282c19:dd:ec00:c25:c25e:dd:ddda:20b5
1832c19:dd:ec00:c25:c25e:dd:ddda:20b6/1282c19:dd:ec00:c25:c25e:dd:ddda:20b6
1842c19:dd:ec00:c25:c25e:dd:ddda:20b7/1282c19:dd:ec00:c25:c25e:dd:ddda:20b7
1852c19:dd:ec00:c25:c25e:dd:ddda:20b8/1282c19:dd:ec00:c25:c25e:dd:ddda:20b8
1862c19:dd:ec00:c25:c25e:dd:ddda:20b9/1282c19:dd:ec00:c25:c25e:dd:ddda:20b9
1872c19:dd:ec00:c25:c25e:dd:ddda:20ba/1282c19:dd:ec00:c25:c25e:dd:ddda:20ba
1882c19:dd:ec00:c25:c25e:dd:ddda:20bb/1282c19:dd:ec00:c25:c25e:dd:ddda:20bb
1892c19:dd:ec00:c25:c25e:dd:ddda:20bc/1282c19:dd:ec00:c25:c25e:dd:ddda:20bc
1902c19:dd:ec00:c25:c25e:dd:ddda:20bd/1282c19:dd:ec00:c25:c25e:dd:ddda:20bd
1912c19:dd:ec00:c25:c25e:dd:ddda:20be/1282c19:dd:ec00:c25:c25e:dd:ddda:20be
1922c19:dd:ec00:c25:c25e:dd:ddda:20bf/1282c19:dd:ec00:c25:c25e:dd:ddda:20bf
1932c19:dd:ec00:c25:c25e:dd:ddda:20c0/1282c19:dd:ec00:c25:c25e:dd:ddda:20c0
1942c19:dd:ec00:c25:c25e:dd:ddda:20c1/1282c19:dd:ec00:c25:c25e:dd:ddda:20c1
1952c19:dd:ec00:c25:c25e:dd:ddda:20c2/1282c19:dd:ec00:c25:c25e:dd:ddda:20c2
1962c19:dd:ec00:c25:c25e:dd:ddda:20c3/1282c19:dd:ec00:c25:c25e:dd:ddda:20c3
1972c19:dd:ec00:c25:c25e:dd:ddda:20c4/1282c19:dd:ec00:c25:c25e:dd:ddda:20c4
1982c19:dd:ec00:c25:c25e:dd:ddda:20c5/1282c19:dd:ec00:c25:c25e:dd:ddda:20c5
1992c19:dd:ec00:c25:c25e:dd:ddda:20c6/1282c19:dd:ec00:c25:c25e:dd:ddda:20c6
2002c19:dd:ec00:c25:c25e:dd:ddda:20c7/1282c19:dd:ec00:c25:c25e:dd:ddda:20c7
2012c19:dd:ec00:c25:c25e:dd:ddda:20c8/1282c19:dd:ec00:c25:c25e:dd:ddda:20c8
2022c19:dd:ec00:c25:c25e:dd:ddda:20c9/1282c19:dd:ec00:c25:c25e:dd:ddda:20c9
2032c19:dd:ec00:c25:c25e:dd:ddda:20ca/1282c19:dd:ec00:c25:c25e:dd:ddda:20ca
2042c19:dd:ec00:c25:c25e:dd:ddda:20cb/1282c19:dd:ec00:c25:c25e:dd:ddda:20cb
2052c19:dd:ec00:c25:c25e:dd:ddda:20cc/1282c19:dd:ec00:c25:c25e:dd:ddda:20cc
2062c19:dd:ec00:c25:c25e:dd:ddda:20cd/1282c19:dd:ec00:c25:c25e:dd:ddda:20cd
2072c19:dd:ec00:c25:c25e:dd:ddda:20ce/1282c19:dd:ec00:c25:c25e:dd:ddda:20ce
2082c19:dd:ec00:c25:c25e:dd:ddda:20cf/1282c19:dd:ec00:c25:c25e:dd:ddda:20cf
2092c19:dd:ec00:c25:c25e:dd:ddda:20d0/1282c19:dd:ec00:c25:c25e:dd:ddda:20d0
2102c19:dd:ec00:c25:c25e:dd:ddda:20d1/1282c19:dd:ec00:c25:c25e:dd:ddda:20d1
2112c19:dd:ec00:c25:c25e:dd:ddda:20d2/1282c19:dd:ec00:c25:c25e:dd:ddda:20d2
2122c19:dd:ec00:c25:c25e:dd:ddda:20d3/1282c19:dd:ec00:c25:c25e:dd:ddda:20d3
2132c19:dd:ec00:c25:c25e:dd:ddda:20d4/1282c19:dd:ec00:c25:c25e:dd:ddda:20d4
2142c19:dd:ec00:c25:c25e:dd:ddda:20d5/1282c19:dd:ec00:c25:c25e:dd:ddda:20d5
2152c19:dd:ec00:c25:c25e:dd:ddda:20d6/1282c19:dd:ec00:c25:c25e:dd:ddda:20d6
2162c19:dd:ec00:c25:c25e:dd:ddda:20d7/1282c19:dd:ec00:c25:c25e:dd:ddda:20d7
2172c19:dd:ec00:c25:c25e:dd:ddda:20d8/1282c19:dd:ec00:c25:c25e:dd:ddda:20d8
2182c19:dd:ec00:c25:c25e:dd:ddda:20d9/1282c19:dd:ec00:c25:c25e:dd:ddda:20d9
2192c19:dd:ec00:c25:c25e:dd:ddda:20da/1282c19:dd:ec00:c25:c25e:dd:ddda:20da
2202c19:dd:ec00:c25:c25e:dd:ddda:20db/1282c19:dd:ec00:c25:c25e:dd:ddda:20db
2212c19:dd:ec00:c25:c25e:dd:ddda:20dc/1282c19:dd:ec00:c25:c25e:dd:ddda:20dc
2222c19:dd:ec00:c25:c25e:dd:ddda:20dd/1282c19:dd:ec00:c25:c25e:dd:ddda:20dd
2232c19:dd:ec00:c25:c25e:dd:ddda:20de/1282c19:dd:ec00:c25:c25e:dd:ddda:20de
2242c19:dd:ec00:c25:c25e:dd:ddda:20df/1282c19:dd:ec00:c25:c25e:dd:ddda:20df
2252c19:dd:ec00:c25:c25e:dd:ddda:20e0/1282c19:dd:ec00:c25:c25e:dd:ddda:20e0
2262c19:dd:ec00:c25:c25e:dd:ddda:20e1/1282c19:dd:ec00:c25:c25e:dd:ddda:20e1
2272c19:dd:ec00:c25:c25e:dd:ddda:20e2/1282c19:dd:ec00:c25:c25e:dd:ddda:20e2
2282c19:dd:ec00:c25:c25e:dd:ddda:20e3/1282c19:dd:ec00:c25:c25e:dd:ddda:20e3
2292c19:dd:ec00:c25:c25e:dd:ddda:20e4/1282c19:dd:ec00:c25:c25e:dd:ddda:20e4
2302c19:dd:ec00:c25:c25e:dd:ddda:20e5/1282c19:dd:ec00:c25:c25e:dd:ddda:20e5
2312c19:dd:ec00:c25:c25e:dd:ddda:20e6/1282c19:dd:ec00:c25:c25e:dd:ddda:20e6
2322c19:dd:ec00:c25:c25e:dd:ddda:20e7/1282c19:dd:ec00:c25:c25e:dd:ddda:20e7
2332c19:dd:ec00:c25:c25e:dd:ddda:20e8/1282c19:dd:ec00:c25:c25e:dd:ddda:20e8
2342c19:dd:ec00:c25:c25e:dd:ddda:20e9/1282c19:dd:ec00:c25:c25e:dd:ddda:20e9
2352c19:dd:ec00:c25:c25e:dd:ddda:20ea/1282c19:dd:ec00:c25:c25e:dd:ddda:20ea
2362c19:dd:ec00:c25:c25e:dd:ddda:20eb/1282c19:dd:ec00:c25:c25e:dd:ddda:20eb
2372c19:dd:ec00:c25:c25e:dd:ddda:20ec/1282c19:dd:ec00:c25:c25e:dd:ddda:20ec
2382c19:dd:ec00:c25:c25e:dd:ddda:20ed/1282c19:dd:ec00:c25:c25e:dd:ddda:20ed
2392c19:dd:ec00:c25:c25e:dd:ddda:20ee/1282c19:dd:ec00:c25:c25e:dd:ddda:20ee
2402c19:dd:ec00:c25:c25e:dd:ddda:20ef/1282c19:dd:ec00:c25:c25e:dd:ddda:20ef
2412c19:dd:ec00:c25:c25e:dd:ddda:20f0/1282c19:dd:ec00:c25:c25e:dd:ddda:20f0
2422c19:dd:ec00:c25:c25e:dd:ddda:20f1/1282c19:dd:ec00:c25:c25e:dd:ddda:20f1
2432c19:dd:ec00:c25:c25e:dd:ddda:20f2/1282c19:dd:ec00:c25:c25e:dd:ddda:20f2
2442c19:dd:ec00:c25:c25e:dd:ddda:20f3/1282c19:dd:ec00:c25:c25e:dd:ddda:20f3
2452c19:dd:ec00:c25:c25e:dd:ddda:20f4/1282c19:dd:ec00:c25:c25e:dd:ddda:20f4
2462c19:dd:ec00:c25:c25e:dd:ddda:20f5/1282c19:dd:ec00:c25:c25e:dd:ddda:20f5
2472c19:dd:ec00:c25:c25e:dd:ddda:20f6/1282c19:dd:ec00:c25:c25e:dd:ddda:20f6
2482c19:dd:ec00:c25:c25e:dd:ddda:20f7/1282c19:dd:ec00:c25:c25e:dd:ddda:20f7
2492c19:dd:ec00:c25:c25e:dd:ddda:20f8/1282c19:dd:ec00:c25:c25e:dd:ddda:20f8
2502c19:dd:ec00:c25:c25e:dd:ddda:20f9/1282c19:dd:ec00:c25:c25e:dd:ddda:20f9
2512c19:dd:ec00:c25:c25e:dd:ddda:20fa/1282c19:dd:ec00:c25:c25e:dd:ddda:20fa
2522c19:dd:ec00:c25:c25e:dd:ddda:20fb/1282c19:dd:ec00:c25:c25e:dd:ddda:20fb
2532c19:dd:ec00:c25:c25e:dd:ddda:20fc/1282c19:dd:ec00:c25:c25e:dd:ddda:20fc
2542c19:dd:ec00:c25:c25e:dd:ddda:20fd/1282c19:dd:ec00:c25:c25e:dd:ddda:20fd
2552c19:dd:ec00:c25:c25e:dd:ddda:20fe/1282c19:dd:ec00:c25:c25e:dd:ddda:20fe
2562c19:dd:ec00:c25:c25e:dd:ddda:20ff/1282c19:dd:ec00:c25:c25e:dd:ddda:20ff

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.