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/120
Addresses256
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:94de:a100/120
First address
2c19:dd:d9:dd:c25:c25:94de:a100
Last address
2c19:dd:d9:dd:c25:c25:94de:a1ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:a100
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
1.a.e.d.4.9.5.2.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
/121 (2)/122 (4)/123 (8)/124 (16)/127 (128)/128 (256)

2c19:dd:d9:dd:c25:c25:94de:a100/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:a100/1282c19:dd:d9:dd:c25:c25:94de:a100
22c19:dd:d9:dd:c25:c25:94de:a101/1282c19:dd:d9:dd:c25:c25:94de:a101
32c19:dd:d9:dd:c25:c25:94de:a102/1282c19:dd:d9:dd:c25:c25:94de:a102
42c19:dd:d9:dd:c25:c25:94de:a103/1282c19:dd:d9:dd:c25:c25:94de:a103
52c19:dd:d9:dd:c25:c25:94de:a104/1282c19:dd:d9:dd:c25:c25:94de:a104
62c19:dd:d9:dd:c25:c25:94de:a105/1282c19:dd:d9:dd:c25:c25:94de:a105
72c19:dd:d9:dd:c25:c25:94de:a106/1282c19:dd:d9:dd:c25:c25:94de:a106
82c19:dd:d9:dd:c25:c25:94de:a107/1282c19:dd:d9:dd:c25:c25:94de:a107
92c19:dd:d9:dd:c25:c25:94de:a108/1282c19:dd:d9:dd:c25:c25:94de:a108
102c19:dd:d9:dd:c25:c25:94de:a109/1282c19:dd:d9:dd:c25:c25:94de:a109
112c19:dd:d9:dd:c25:c25:94de:a10a/1282c19:dd:d9:dd:c25:c25:94de:a10a
122c19:dd:d9:dd:c25:c25:94de:a10b/1282c19:dd:d9:dd:c25:c25:94de:a10b
132c19:dd:d9:dd:c25:c25:94de:a10c/1282c19:dd:d9:dd:c25:c25:94de:a10c
142c19:dd:d9:dd:c25:c25:94de:a10d/1282c19:dd:d9:dd:c25:c25:94de:a10d
152c19:dd:d9:dd:c25:c25:94de:a10e/1282c19:dd:d9:dd:c25:c25:94de:a10e
162c19:dd:d9:dd:c25:c25:94de:a10f/1282c19:dd:d9:dd:c25:c25:94de:a10f
172c19:dd:d9:dd:c25:c25:94de:a110/1282c19:dd:d9:dd:c25:c25:94de:a110
182c19:dd:d9:dd:c25:c25:94de:a111/1282c19:dd:d9:dd:c25:c25:94de:a111
192c19:dd:d9:dd:c25:c25:94de:a112/1282c19:dd:d9:dd:c25:c25:94de:a112
202c19:dd:d9:dd:c25:c25:94de:a113/1282c19:dd:d9:dd:c25:c25:94de:a113
212c19:dd:d9:dd:c25:c25:94de:a114/1282c19:dd:d9:dd:c25:c25:94de:a114
222c19:dd:d9:dd:c25:c25:94de:a115/1282c19:dd:d9:dd:c25:c25:94de:a115
232c19:dd:d9:dd:c25:c25:94de:a116/1282c19:dd:d9:dd:c25:c25:94de:a116
242c19:dd:d9:dd:c25:c25:94de:a117/1282c19:dd:d9:dd:c25:c25:94de:a117
252c19:dd:d9:dd:c25:c25:94de:a118/1282c19:dd:d9:dd:c25:c25:94de:a118
262c19:dd:d9:dd:c25:c25:94de:a119/1282c19:dd:d9:dd:c25:c25:94de:a119
272c19:dd:d9:dd:c25:c25:94de:a11a/1282c19:dd:d9:dd:c25:c25:94de:a11a
282c19:dd:d9:dd:c25:c25:94de:a11b/1282c19:dd:d9:dd:c25:c25:94de:a11b
292c19:dd:d9:dd:c25:c25:94de:a11c/1282c19:dd:d9:dd:c25:c25:94de:a11c
302c19:dd:d9:dd:c25:c25:94de:a11d/1282c19:dd:d9:dd:c25:c25:94de:a11d
312c19:dd:d9:dd:c25:c25:94de:a11e/1282c19:dd:d9:dd:c25:c25:94de:a11e
322c19:dd:d9:dd:c25:c25:94de:a11f/1282c19:dd:d9:dd:c25:c25:94de:a11f
332c19:dd:d9:dd:c25:c25:94de:a120/1282c19:dd:d9:dd:c25:c25:94de:a120
342c19:dd:d9:dd:c25:c25:94de:a121/1282c19:dd:d9:dd:c25:c25:94de:a121
352c19:dd:d9:dd:c25:c25:94de:a122/1282c19:dd:d9:dd:c25:c25:94de:a122
362c19:dd:d9:dd:c25:c25:94de:a123/1282c19:dd:d9:dd:c25:c25:94de:a123
372c19:dd:d9:dd:c25:c25:94de:a124/1282c19:dd:d9:dd:c25:c25:94de:a124
382c19:dd:d9:dd:c25:c25:94de:a125/1282c19:dd:d9:dd:c25:c25:94de:a125
392c19:dd:d9:dd:c25:c25:94de:a126/1282c19:dd:d9:dd:c25:c25:94de:a126
402c19:dd:d9:dd:c25:c25:94de:a127/1282c19:dd:d9:dd:c25:c25:94de:a127
412c19:dd:d9:dd:c25:c25:94de:a128/1282c19:dd:d9:dd:c25:c25:94de:a128
422c19:dd:d9:dd:c25:c25:94de:a129/1282c19:dd:d9:dd:c25:c25:94de:a129
432c19:dd:d9:dd:c25:c25:94de:a12a/1282c19:dd:d9:dd:c25:c25:94de:a12a
442c19:dd:d9:dd:c25:c25:94de:a12b/1282c19:dd:d9:dd:c25:c25:94de:a12b
452c19:dd:d9:dd:c25:c25:94de:a12c/1282c19:dd:d9:dd:c25:c25:94de:a12c
462c19:dd:d9:dd:c25:c25:94de:a12d/1282c19:dd:d9:dd:c25:c25:94de:a12d
472c19:dd:d9:dd:c25:c25:94de:a12e/1282c19:dd:d9:dd:c25:c25:94de:a12e
482c19:dd:d9:dd:c25:c25:94de:a12f/1282c19:dd:d9:dd:c25:c25:94de:a12f
492c19:dd:d9:dd:c25:c25:94de:a130/1282c19:dd:d9:dd:c25:c25:94de:a130
502c19:dd:d9:dd:c25:c25:94de:a131/1282c19:dd:d9:dd:c25:c25:94de:a131
512c19:dd:d9:dd:c25:c25:94de:a132/1282c19:dd:d9:dd:c25:c25:94de:a132
522c19:dd:d9:dd:c25:c25:94de:a133/1282c19:dd:d9:dd:c25:c25:94de:a133
532c19:dd:d9:dd:c25:c25:94de:a134/1282c19:dd:d9:dd:c25:c25:94de:a134
542c19:dd:d9:dd:c25:c25:94de:a135/1282c19:dd:d9:dd:c25:c25:94de:a135
552c19:dd:d9:dd:c25:c25:94de:a136/1282c19:dd:d9:dd:c25:c25:94de:a136
562c19:dd:d9:dd:c25:c25:94de:a137/1282c19:dd:d9:dd:c25:c25:94de:a137
572c19:dd:d9:dd:c25:c25:94de:a138/1282c19:dd:d9:dd:c25:c25:94de:a138
582c19:dd:d9:dd:c25:c25:94de:a139/1282c19:dd:d9:dd:c25:c25:94de:a139
592c19:dd:d9:dd:c25:c25:94de:a13a/1282c19:dd:d9:dd:c25:c25:94de:a13a
602c19:dd:d9:dd:c25:c25:94de:a13b/1282c19:dd:d9:dd:c25:c25:94de:a13b
612c19:dd:d9:dd:c25:c25:94de:a13c/1282c19:dd:d9:dd:c25:c25:94de:a13c
622c19:dd:d9:dd:c25:c25:94de:a13d/1282c19:dd:d9:dd:c25:c25:94de:a13d
632c19:dd:d9:dd:c25:c25:94de:a13e/1282c19:dd:d9:dd:c25:c25:94de:a13e
642c19:dd:d9:dd:c25:c25:94de:a13f/1282c19:dd:d9:dd:c25:c25:94de:a13f
652c19:dd:d9:dd:c25:c25:94de:a140/1282c19:dd:d9:dd:c25:c25:94de:a140
662c19:dd:d9:dd:c25:c25:94de:a141/1282c19:dd:d9:dd:c25:c25:94de:a141
672c19:dd:d9:dd:c25:c25:94de:a142/1282c19:dd:d9:dd:c25:c25:94de:a142
682c19:dd:d9:dd:c25:c25:94de:a143/1282c19:dd:d9:dd:c25:c25:94de:a143
692c19:dd:d9:dd:c25:c25:94de:a144/1282c19:dd:d9:dd:c25:c25:94de:a144
702c19:dd:d9:dd:c25:c25:94de:a145/1282c19:dd:d9:dd:c25:c25:94de:a145
712c19:dd:d9:dd:c25:c25:94de:a146/1282c19:dd:d9:dd:c25:c25:94de:a146
722c19:dd:d9:dd:c25:c25:94de:a147/1282c19:dd:d9:dd:c25:c25:94de:a147
732c19:dd:d9:dd:c25:c25:94de:a148/1282c19:dd:d9:dd:c25:c25:94de:a148
742c19:dd:d9:dd:c25:c25:94de:a149/1282c19:dd:d9:dd:c25:c25:94de:a149
752c19:dd:d9:dd:c25:c25:94de:a14a/1282c19:dd:d9:dd:c25:c25:94de:a14a
762c19:dd:d9:dd:c25:c25:94de:a14b/1282c19:dd:d9:dd:c25:c25:94de:a14b
772c19:dd:d9:dd:c25:c25:94de:a14c/1282c19:dd:d9:dd:c25:c25:94de:a14c
782c19:dd:d9:dd:c25:c25:94de:a14d/1282c19:dd:d9:dd:c25:c25:94de:a14d
792c19:dd:d9:dd:c25:c25:94de:a14e/1282c19:dd:d9:dd:c25:c25:94de:a14e
802c19:dd:d9:dd:c25:c25:94de:a14f/1282c19:dd:d9:dd:c25:c25:94de:a14f
812c19:dd:d9:dd:c25:c25:94de:a150/1282c19:dd:d9:dd:c25:c25:94de:a150
822c19:dd:d9:dd:c25:c25:94de:a151/1282c19:dd:d9:dd:c25:c25:94de:a151
832c19:dd:d9:dd:c25:c25:94de:a152/1282c19:dd:d9:dd:c25:c25:94de:a152
842c19:dd:d9:dd:c25:c25:94de:a153/1282c19:dd:d9:dd:c25:c25:94de:a153
852c19:dd:d9:dd:c25:c25:94de:a154/1282c19:dd:d9:dd:c25:c25:94de:a154
862c19:dd:d9:dd:c25:c25:94de:a155/1282c19:dd:d9:dd:c25:c25:94de:a155
872c19:dd:d9:dd:c25:c25:94de:a156/1282c19:dd:d9:dd:c25:c25:94de:a156
882c19:dd:d9:dd:c25:c25:94de:a157/1282c19:dd:d9:dd:c25:c25:94de:a157
892c19:dd:d9:dd:c25:c25:94de:a158/1282c19:dd:d9:dd:c25:c25:94de:a158
902c19:dd:d9:dd:c25:c25:94de:a159/1282c19:dd:d9:dd:c25:c25:94de:a159
912c19:dd:d9:dd:c25:c25:94de:a15a/1282c19:dd:d9:dd:c25:c25:94de:a15a
922c19:dd:d9:dd:c25:c25:94de:a15b/1282c19:dd:d9:dd:c25:c25:94de:a15b
932c19:dd:d9:dd:c25:c25:94de:a15c/1282c19:dd:d9:dd:c25:c25:94de:a15c
942c19:dd:d9:dd:c25:c25:94de:a15d/1282c19:dd:d9:dd:c25:c25:94de:a15d
952c19:dd:d9:dd:c25:c25:94de:a15e/1282c19:dd:d9:dd:c25:c25:94de:a15e
962c19:dd:d9:dd:c25:c25:94de:a15f/1282c19:dd:d9:dd:c25:c25:94de:a15f
972c19:dd:d9:dd:c25:c25:94de:a160/1282c19:dd:d9:dd:c25:c25:94de:a160
982c19:dd:d9:dd:c25:c25:94de:a161/1282c19:dd:d9:dd:c25:c25:94de:a161
992c19:dd:d9:dd:c25:c25:94de:a162/1282c19:dd:d9:dd:c25:c25:94de:a162
1002c19:dd:d9:dd:c25:c25:94de:a163/1282c19:dd:d9:dd:c25:c25:94de:a163
1012c19:dd:d9:dd:c25:c25:94de:a164/1282c19:dd:d9:dd:c25:c25:94de:a164
1022c19:dd:d9:dd:c25:c25:94de:a165/1282c19:dd:d9:dd:c25:c25:94de:a165
1032c19:dd:d9:dd:c25:c25:94de:a166/1282c19:dd:d9:dd:c25:c25:94de:a166
1042c19:dd:d9:dd:c25:c25:94de:a167/1282c19:dd:d9:dd:c25:c25:94de:a167
1052c19:dd:d9:dd:c25:c25:94de:a168/1282c19:dd:d9:dd:c25:c25:94de:a168
1062c19:dd:d9:dd:c25:c25:94de:a169/1282c19:dd:d9:dd:c25:c25:94de:a169
1072c19:dd:d9:dd:c25:c25:94de:a16a/1282c19:dd:d9:dd:c25:c25:94de:a16a
1082c19:dd:d9:dd:c25:c25:94de:a16b/1282c19:dd:d9:dd:c25:c25:94de:a16b
1092c19:dd:d9:dd:c25:c25:94de:a16c/1282c19:dd:d9:dd:c25:c25:94de:a16c
1102c19:dd:d9:dd:c25:c25:94de:a16d/1282c19:dd:d9:dd:c25:c25:94de:a16d
1112c19:dd:d9:dd:c25:c25:94de:a16e/1282c19:dd:d9:dd:c25:c25:94de:a16e
1122c19:dd:d9:dd:c25:c25:94de:a16f/1282c19:dd:d9:dd:c25:c25:94de:a16f
1132c19:dd:d9:dd:c25:c25:94de:a170/1282c19:dd:d9:dd:c25:c25:94de:a170
1142c19:dd:d9:dd:c25:c25:94de:a171/1282c19:dd:d9:dd:c25:c25:94de:a171
1152c19:dd:d9:dd:c25:c25:94de:a172/1282c19:dd:d9:dd:c25:c25:94de:a172
1162c19:dd:d9:dd:c25:c25:94de:a173/1282c19:dd:d9:dd:c25:c25:94de:a173
1172c19:dd:d9:dd:c25:c25:94de:a174/1282c19:dd:d9:dd:c25:c25:94de:a174
1182c19:dd:d9:dd:c25:c25:94de:a175/1282c19:dd:d9:dd:c25:c25:94de:a175
1192c19:dd:d9:dd:c25:c25:94de:a176/1282c19:dd:d9:dd:c25:c25:94de:a176
1202c19:dd:d9:dd:c25:c25:94de:a177/1282c19:dd:d9:dd:c25:c25:94de:a177
1212c19:dd:d9:dd:c25:c25:94de:a178/1282c19:dd:d9:dd:c25:c25:94de:a178
1222c19:dd:d9:dd:c25:c25:94de:a179/1282c19:dd:d9:dd:c25:c25:94de:a179
1232c19:dd:d9:dd:c25:c25:94de:a17a/1282c19:dd:d9:dd:c25:c25:94de:a17a
1242c19:dd:d9:dd:c25:c25:94de:a17b/1282c19:dd:d9:dd:c25:c25:94de:a17b
1252c19:dd:d9:dd:c25:c25:94de:a17c/1282c19:dd:d9:dd:c25:c25:94de:a17c
1262c19:dd:d9:dd:c25:c25:94de:a17d/1282c19:dd:d9:dd:c25:c25:94de:a17d
1272c19:dd:d9:dd:c25:c25:94de:a17e/1282c19:dd:d9:dd:c25:c25:94de:a17e
1282c19:dd:d9:dd:c25:c25:94de:a17f/1282c19:dd:d9:dd:c25:c25:94de:a17f
1292c19:dd:d9:dd:c25:c25:94de:a180/1282c19:dd:d9:dd:c25:c25:94de:a180
1302c19:dd:d9:dd:c25:c25:94de:a181/1282c19:dd:d9:dd:c25:c25:94de:a181
1312c19:dd:d9:dd:c25:c25:94de:a182/1282c19:dd:d9:dd:c25:c25:94de:a182
1322c19:dd:d9:dd:c25:c25:94de:a183/1282c19:dd:d9:dd:c25:c25:94de:a183
1332c19:dd:d9:dd:c25:c25:94de:a184/1282c19:dd:d9:dd:c25:c25:94de:a184
1342c19:dd:d9:dd:c25:c25:94de:a185/1282c19:dd:d9:dd:c25:c25:94de:a185
1352c19:dd:d9:dd:c25:c25:94de:a186/1282c19:dd:d9:dd:c25:c25:94de:a186
1362c19:dd:d9:dd:c25:c25:94de:a187/1282c19:dd:d9:dd:c25:c25:94de:a187
1372c19:dd:d9:dd:c25:c25:94de:a188/1282c19:dd:d9:dd:c25:c25:94de:a188
1382c19:dd:d9:dd:c25:c25:94de:a189/1282c19:dd:d9:dd:c25:c25:94de:a189
1392c19:dd:d9:dd:c25:c25:94de:a18a/1282c19:dd:d9:dd:c25:c25:94de:a18a
1402c19:dd:d9:dd:c25:c25:94de:a18b/1282c19:dd:d9:dd:c25:c25:94de:a18b
1412c19:dd:d9:dd:c25:c25:94de:a18c/1282c19:dd:d9:dd:c25:c25:94de:a18c
1422c19:dd:d9:dd:c25:c25:94de:a18d/1282c19:dd:d9:dd:c25:c25:94de:a18d
1432c19:dd:d9:dd:c25:c25:94de:a18e/1282c19:dd:d9:dd:c25:c25:94de:a18e
1442c19:dd:d9:dd:c25:c25:94de:a18f/1282c19:dd:d9:dd:c25:c25:94de:a18f
1452c19:dd:d9:dd:c25:c25:94de:a190/1282c19:dd:d9:dd:c25:c25:94de:a190
1462c19:dd:d9:dd:c25:c25:94de:a191/1282c19:dd:d9:dd:c25:c25:94de:a191
1472c19:dd:d9:dd:c25:c25:94de:a192/1282c19:dd:d9:dd:c25:c25:94de:a192
1482c19:dd:d9:dd:c25:c25:94de:a193/1282c19:dd:d9:dd:c25:c25:94de:a193
1492c19:dd:d9:dd:c25:c25:94de:a194/1282c19:dd:d9:dd:c25:c25:94de:a194
1502c19:dd:d9:dd:c25:c25:94de:a195/1282c19:dd:d9:dd:c25:c25:94de:a195
1512c19:dd:d9:dd:c25:c25:94de:a196/1282c19:dd:d9:dd:c25:c25:94de:a196
1522c19:dd:d9:dd:c25:c25:94de:a197/1282c19:dd:d9:dd:c25:c25:94de:a197
1532c19:dd:d9:dd:c25:c25:94de:a198/1282c19:dd:d9:dd:c25:c25:94de:a198
1542c19:dd:d9:dd:c25:c25:94de:a199/1282c19:dd:d9:dd:c25:c25:94de:a199
1552c19:dd:d9:dd:c25:c25:94de:a19a/1282c19:dd:d9:dd:c25:c25:94de:a19a
1562c19:dd:d9:dd:c25:c25:94de:a19b/1282c19:dd:d9:dd:c25:c25:94de:a19b
1572c19:dd:d9:dd:c25:c25:94de:a19c/1282c19:dd:d9:dd:c25:c25:94de:a19c
1582c19:dd:d9:dd:c25:c25:94de:a19d/1282c19:dd:d9:dd:c25:c25:94de:a19d
1592c19:dd:d9:dd:c25:c25:94de:a19e/1282c19:dd:d9:dd:c25:c25:94de:a19e
1602c19:dd:d9:dd:c25:c25:94de:a19f/1282c19:dd:d9:dd:c25:c25:94de:a19f
1612c19:dd:d9:dd:c25:c25:94de:a1a0/1282c19:dd:d9:dd:c25:c25:94de:a1a0
1622c19:dd:d9:dd:c25:c25:94de:a1a1/1282c19:dd:d9:dd:c25:c25:94de:a1a1
1632c19:dd:d9:dd:c25:c25:94de:a1a2/1282c19:dd:d9:dd:c25:c25:94de:a1a2
1642c19:dd:d9:dd:c25:c25:94de:a1a3/1282c19:dd:d9:dd:c25:c25:94de:a1a3
1652c19:dd:d9:dd:c25:c25:94de:a1a4/1282c19:dd:d9:dd:c25:c25:94de:a1a4
1662c19:dd:d9:dd:c25:c25:94de:a1a5/1282c19:dd:d9:dd:c25:c25:94de:a1a5
1672c19:dd:d9:dd:c25:c25:94de:a1a6/1282c19:dd:d9:dd:c25:c25:94de:a1a6
1682c19:dd:d9:dd:c25:c25:94de:a1a7/1282c19:dd:d9:dd:c25:c25:94de:a1a7
1692c19:dd:d9:dd:c25:c25:94de:a1a8/1282c19:dd:d9:dd:c25:c25:94de:a1a8
1702c19:dd:d9:dd:c25:c25:94de:a1a9/1282c19:dd:d9:dd:c25:c25:94de:a1a9
1712c19:dd:d9:dd:c25:c25:94de:a1aa/1282c19:dd:d9:dd:c25:c25:94de:a1aa
1722c19:dd:d9:dd:c25:c25:94de:a1ab/1282c19:dd:d9:dd:c25:c25:94de:a1ab
1732c19:dd:d9:dd:c25:c25:94de:a1ac/1282c19:dd:d9:dd:c25:c25:94de:a1ac
1742c19:dd:d9:dd:c25:c25:94de:a1ad/1282c19:dd:d9:dd:c25:c25:94de:a1ad
1752c19:dd:d9:dd:c25:c25:94de:a1ae/1282c19:dd:d9:dd:c25:c25:94de:a1ae
1762c19:dd:d9:dd:c25:c25:94de:a1af/1282c19:dd:d9:dd:c25:c25:94de:a1af
1772c19:dd:d9:dd:c25:c25:94de:a1b0/1282c19:dd:d9:dd:c25:c25:94de:a1b0
1782c19:dd:d9:dd:c25:c25:94de:a1b1/1282c19:dd:d9:dd:c25:c25:94de:a1b1
1792c19:dd:d9:dd:c25:c25:94de:a1b2/1282c19:dd:d9:dd:c25:c25:94de:a1b2
1802c19:dd:d9:dd:c25:c25:94de:a1b3/1282c19:dd:d9:dd:c25:c25:94de:a1b3
1812c19:dd:d9:dd:c25:c25:94de:a1b4/1282c19:dd:d9:dd:c25:c25:94de:a1b4
1822c19:dd:d9:dd:c25:c25:94de:a1b5/1282c19:dd:d9:dd:c25:c25:94de:a1b5
1832c19:dd:d9:dd:c25:c25:94de:a1b6/1282c19:dd:d9:dd:c25:c25:94de:a1b6
1842c19:dd:d9:dd:c25:c25:94de:a1b7/1282c19:dd:d9:dd:c25:c25:94de:a1b7
1852c19:dd:d9:dd:c25:c25:94de:a1b8/1282c19:dd:d9:dd:c25:c25:94de:a1b8
1862c19:dd:d9:dd:c25:c25:94de:a1b9/1282c19:dd:d9:dd:c25:c25:94de:a1b9
1872c19:dd:d9:dd:c25:c25:94de:a1ba/1282c19:dd:d9:dd:c25:c25:94de:a1ba
1882c19:dd:d9:dd:c25:c25:94de:a1bb/1282c19:dd:d9:dd:c25:c25:94de:a1bb
1892c19:dd:d9:dd:c25:c25:94de:a1bc/1282c19:dd:d9:dd:c25:c25:94de:a1bc
1902c19:dd:d9:dd:c25:c25:94de:a1bd/1282c19:dd:d9:dd:c25:c25:94de:a1bd
1912c19:dd:d9:dd:c25:c25:94de:a1be/1282c19:dd:d9:dd:c25:c25:94de:a1be
1922c19:dd:d9:dd:c25:c25:94de:a1bf/1282c19:dd:d9:dd:c25:c25:94de:a1bf
1932c19:dd:d9:dd:c25:c25:94de:a1c0/1282c19:dd:d9:dd:c25:c25:94de:a1c0
1942c19:dd:d9:dd:c25:c25:94de:a1c1/1282c19:dd:d9:dd:c25:c25:94de:a1c1
1952c19:dd:d9:dd:c25:c25:94de:a1c2/1282c19:dd:d9:dd:c25:c25:94de:a1c2
1962c19:dd:d9:dd:c25:c25:94de:a1c3/1282c19:dd:d9:dd:c25:c25:94de:a1c3
1972c19:dd:d9:dd:c25:c25:94de:a1c4/1282c19:dd:d9:dd:c25:c25:94de:a1c4
1982c19:dd:d9:dd:c25:c25:94de:a1c5/1282c19:dd:d9:dd:c25:c25:94de:a1c5
1992c19:dd:d9:dd:c25:c25:94de:a1c6/1282c19:dd:d9:dd:c25:c25:94de:a1c6
2002c19:dd:d9:dd:c25:c25:94de:a1c7/1282c19:dd:d9:dd:c25:c25:94de:a1c7
2012c19:dd:d9:dd:c25:c25:94de:a1c8/1282c19:dd:d9:dd:c25:c25:94de:a1c8
2022c19:dd:d9:dd:c25:c25:94de:a1c9/1282c19:dd:d9:dd:c25:c25:94de:a1c9
2032c19:dd:d9:dd:c25:c25:94de:a1ca/1282c19:dd:d9:dd:c25:c25:94de:a1ca
2042c19:dd:d9:dd:c25:c25:94de:a1cb/1282c19:dd:d9:dd:c25:c25:94de:a1cb
2052c19:dd:d9:dd:c25:c25:94de:a1cc/1282c19:dd:d9:dd:c25:c25:94de:a1cc
2062c19:dd:d9:dd:c25:c25:94de:a1cd/1282c19:dd:d9:dd:c25:c25:94de:a1cd
2072c19:dd:d9:dd:c25:c25:94de:a1ce/1282c19:dd:d9:dd:c25:c25:94de:a1ce
2082c19:dd:d9:dd:c25:c25:94de:a1cf/1282c19:dd:d9:dd:c25:c25:94de:a1cf
2092c19:dd:d9:dd:c25:c25:94de:a1d0/1282c19:dd:d9:dd:c25:c25:94de:a1d0
2102c19:dd:d9:dd:c25:c25:94de:a1d1/1282c19:dd:d9:dd:c25:c25:94de:a1d1
2112c19:dd:d9:dd:c25:c25:94de:a1d2/1282c19:dd:d9:dd:c25:c25:94de:a1d2
2122c19:dd:d9:dd:c25:c25:94de:a1d3/1282c19:dd:d9:dd:c25:c25:94de:a1d3
2132c19:dd:d9:dd:c25:c25:94de:a1d4/1282c19:dd:d9:dd:c25:c25:94de:a1d4
2142c19:dd:d9:dd:c25:c25:94de:a1d5/1282c19:dd:d9:dd:c25:c25:94de:a1d5
2152c19:dd:d9:dd:c25:c25:94de:a1d6/1282c19:dd:d9:dd:c25:c25:94de:a1d6
2162c19:dd:d9:dd:c25:c25:94de:a1d7/1282c19:dd:d9:dd:c25:c25:94de:a1d7
2172c19:dd:d9:dd:c25:c25:94de:a1d8/1282c19:dd:d9:dd:c25:c25:94de:a1d8
2182c19:dd:d9:dd:c25:c25:94de:a1d9/1282c19:dd:d9:dd:c25:c25:94de:a1d9
2192c19:dd:d9:dd:c25:c25:94de:a1da/1282c19:dd:d9:dd:c25:c25:94de:a1da
2202c19:dd:d9:dd:c25:c25:94de:a1db/1282c19:dd:d9:dd:c25:c25:94de:a1db
2212c19:dd:d9:dd:c25:c25:94de:a1dc/1282c19:dd:d9:dd:c25:c25:94de:a1dc
2222c19:dd:d9:dd:c25:c25:94de:a1dd/1282c19:dd:d9:dd:c25:c25:94de:a1dd
2232c19:dd:d9:dd:c25:c25:94de:a1de/1282c19:dd:d9:dd:c25:c25:94de:a1de
2242c19:dd:d9:dd:c25:c25:94de:a1df/1282c19:dd:d9:dd:c25:c25:94de:a1df
2252c19:dd:d9:dd:c25:c25:94de:a1e0/1282c19:dd:d9:dd:c25:c25:94de:a1e0
2262c19:dd:d9:dd:c25:c25:94de:a1e1/1282c19:dd:d9:dd:c25:c25:94de:a1e1
2272c19:dd:d9:dd:c25:c25:94de:a1e2/1282c19:dd:d9:dd:c25:c25:94de:a1e2
2282c19:dd:d9:dd:c25:c25:94de:a1e3/1282c19:dd:d9:dd:c25:c25:94de:a1e3
2292c19:dd:d9:dd:c25:c25:94de:a1e4/1282c19:dd:d9:dd:c25:c25:94de:a1e4
2302c19:dd:d9:dd:c25:c25:94de:a1e5/1282c19:dd:d9:dd:c25:c25:94de:a1e5
2312c19:dd:d9:dd:c25:c25:94de:a1e6/1282c19:dd:d9:dd:c25:c25:94de:a1e6
2322c19:dd:d9:dd:c25:c25:94de:a1e7/1282c19:dd:d9:dd:c25:c25:94de:a1e7
2332c19:dd:d9:dd:c25:c25:94de:a1e8/1282c19:dd:d9:dd:c25:c25:94de:a1e8
2342c19:dd:d9:dd:c25:c25:94de:a1e9/1282c19:dd:d9:dd:c25:c25:94de:a1e9
2352c19:dd:d9:dd:c25:c25:94de:a1ea/1282c19:dd:d9:dd:c25:c25:94de:a1ea
2362c19:dd:d9:dd:c25:c25:94de:a1eb/1282c19:dd:d9:dd:c25:c25:94de:a1eb
2372c19:dd:d9:dd:c25:c25:94de:a1ec/1282c19:dd:d9:dd:c25:c25:94de:a1ec
2382c19:dd:d9:dd:c25:c25:94de:a1ed/1282c19:dd:d9:dd:c25:c25:94de:a1ed
2392c19:dd:d9:dd:c25:c25:94de:a1ee/1282c19:dd:d9:dd:c25:c25:94de:a1ee
2402c19:dd:d9:dd:c25:c25:94de:a1ef/1282c19:dd:d9:dd:c25:c25:94de:a1ef
2412c19:dd:d9:dd:c25:c25:94de:a1f0/1282c19:dd:d9:dd:c25:c25:94de:a1f0
2422c19:dd:d9:dd:c25:c25:94de:a1f1/1282c19:dd:d9:dd:c25:c25:94de:a1f1
2432c19:dd:d9:dd:c25:c25:94de:a1f2/1282c19:dd:d9:dd:c25:c25:94de:a1f2
2442c19:dd:d9:dd:c25:c25:94de:a1f3/1282c19:dd:d9:dd:c25:c25:94de:a1f3
2452c19:dd:d9:dd:c25:c25:94de:a1f4/1282c19:dd:d9:dd:c25:c25:94de:a1f4
2462c19:dd:d9:dd:c25:c25:94de:a1f5/1282c19:dd:d9:dd:c25:c25:94de:a1f5
2472c19:dd:d9:dd:c25:c25:94de:a1f6/1282c19:dd:d9:dd:c25:c25:94de:a1f6
2482c19:dd:d9:dd:c25:c25:94de:a1f7/1282c19:dd:d9:dd:c25:c25:94de:a1f7
2492c19:dd:d9:dd:c25:c25:94de:a1f8/1282c19:dd:d9:dd:c25:c25:94de:a1f8
2502c19:dd:d9:dd:c25:c25:94de:a1f9/1282c19:dd:d9:dd:c25:c25:94de:a1f9
2512c19:dd:d9:dd:c25:c25:94de:a1fa/1282c19:dd:d9:dd:c25:c25:94de:a1fa
2522c19:dd:d9:dd:c25:c25:94de:a1fb/1282c19:dd:d9:dd:c25:c25:94de:a1fb
2532c19:dd:d9:dd:c25:c25:94de:a1fc/1282c19:dd:d9:dd:c25:c25:94de:a1fc
2542c19:dd:d9:dd:c25:c25:94de:a1fd/1282c19:dd:d9:dd:c25:c25:94de:a1fd
2552c19:dd:d9:dd:c25:c25:94de:a1fe/1282c19:dd:d9:dd:c25:c25:94de:a1fe
2562c19:dd:d9:dd:c25:c25:94de:a1ff/1282c19:dd:d9:dd:c25:c25:94de:a1ff

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.