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/119
Addresses512
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:94de:a200/119
First address
2c19:dd:d9:dd:c25:c25:94de:a200
Last address
2c19:dd:d9:dd:c25:c25:94de:a3ff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:a200
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
2.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
3.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
/119 is not on a 4-bit boundary, so it takes 2 /120 zones.
Split into smaller subnets/127
/120 (2)/121 (4)/122 (8)/123 (16)/124 (32)/127 (256)/128 (512)

2c19:dd:d9:dd:c25:c25:94de:a200/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:a200/1272c19:dd:d9:dd:c25:c25:94de:a201
22c19:dd:d9:dd:c25:c25:94de:a202/1272c19:dd:d9:dd:c25:c25:94de:a203
32c19:dd:d9:dd:c25:c25:94de:a204/1272c19:dd:d9:dd:c25:c25:94de:a205
42c19:dd:d9:dd:c25:c25:94de:a206/1272c19:dd:d9:dd:c25:c25:94de:a207
52c19:dd:d9:dd:c25:c25:94de:a208/1272c19:dd:d9:dd:c25:c25:94de:a209
62c19:dd:d9:dd:c25:c25:94de:a20a/1272c19:dd:d9:dd:c25:c25:94de:a20b
72c19:dd:d9:dd:c25:c25:94de:a20c/1272c19:dd:d9:dd:c25:c25:94de:a20d
82c19:dd:d9:dd:c25:c25:94de:a20e/1272c19:dd:d9:dd:c25:c25:94de:a20f
92c19:dd:d9:dd:c25:c25:94de:a210/1272c19:dd:d9:dd:c25:c25:94de:a211
102c19:dd:d9:dd:c25:c25:94de:a212/1272c19:dd:d9:dd:c25:c25:94de:a213
112c19:dd:d9:dd:c25:c25:94de:a214/1272c19:dd:d9:dd:c25:c25:94de:a215
122c19:dd:d9:dd:c25:c25:94de:a216/1272c19:dd:d9:dd:c25:c25:94de:a217
132c19:dd:d9:dd:c25:c25:94de:a218/1272c19:dd:d9:dd:c25:c25:94de:a219
142c19:dd:d9:dd:c25:c25:94de:a21a/1272c19:dd:d9:dd:c25:c25:94de:a21b
152c19:dd:d9:dd:c25:c25:94de:a21c/1272c19:dd:d9:dd:c25:c25:94de:a21d
162c19:dd:d9:dd:c25:c25:94de:a21e/1272c19:dd:d9:dd:c25:c25:94de:a21f
172c19:dd:d9:dd:c25:c25:94de:a220/1272c19:dd:d9:dd:c25:c25:94de:a221
182c19:dd:d9:dd:c25:c25:94de:a222/1272c19:dd:d9:dd:c25:c25:94de:a223
192c19:dd:d9:dd:c25:c25:94de:a224/1272c19:dd:d9:dd:c25:c25:94de:a225
202c19:dd:d9:dd:c25:c25:94de:a226/1272c19:dd:d9:dd:c25:c25:94de:a227
212c19:dd:d9:dd:c25:c25:94de:a228/1272c19:dd:d9:dd:c25:c25:94de:a229
222c19:dd:d9:dd:c25:c25:94de:a22a/1272c19:dd:d9:dd:c25:c25:94de:a22b
232c19:dd:d9:dd:c25:c25:94de:a22c/1272c19:dd:d9:dd:c25:c25:94de:a22d
242c19:dd:d9:dd:c25:c25:94de:a22e/1272c19:dd:d9:dd:c25:c25:94de:a22f
252c19:dd:d9:dd:c25:c25:94de:a230/1272c19:dd:d9:dd:c25:c25:94de:a231
262c19:dd:d9:dd:c25:c25:94de:a232/1272c19:dd:d9:dd:c25:c25:94de:a233
272c19:dd:d9:dd:c25:c25:94de:a234/1272c19:dd:d9:dd:c25:c25:94de:a235
282c19:dd:d9:dd:c25:c25:94de:a236/1272c19:dd:d9:dd:c25:c25:94de:a237
292c19:dd:d9:dd:c25:c25:94de:a238/1272c19:dd:d9:dd:c25:c25:94de:a239
302c19:dd:d9:dd:c25:c25:94de:a23a/1272c19:dd:d9:dd:c25:c25:94de:a23b
312c19:dd:d9:dd:c25:c25:94de:a23c/1272c19:dd:d9:dd:c25:c25:94de:a23d
322c19:dd:d9:dd:c25:c25:94de:a23e/1272c19:dd:d9:dd:c25:c25:94de:a23f
332c19:dd:d9:dd:c25:c25:94de:a240/1272c19:dd:d9:dd:c25:c25:94de:a241
342c19:dd:d9:dd:c25:c25:94de:a242/1272c19:dd:d9:dd:c25:c25:94de:a243
352c19:dd:d9:dd:c25:c25:94de:a244/1272c19:dd:d9:dd:c25:c25:94de:a245
362c19:dd:d9:dd:c25:c25:94de:a246/1272c19:dd:d9:dd:c25:c25:94de:a247
372c19:dd:d9:dd:c25:c25:94de:a248/1272c19:dd:d9:dd:c25:c25:94de:a249
382c19:dd:d9:dd:c25:c25:94de:a24a/1272c19:dd:d9:dd:c25:c25:94de:a24b
392c19:dd:d9:dd:c25:c25:94de:a24c/1272c19:dd:d9:dd:c25:c25:94de:a24d
402c19:dd:d9:dd:c25:c25:94de:a24e/1272c19:dd:d9:dd:c25:c25:94de:a24f
412c19:dd:d9:dd:c25:c25:94de:a250/1272c19:dd:d9:dd:c25:c25:94de:a251
422c19:dd:d9:dd:c25:c25:94de:a252/1272c19:dd:d9:dd:c25:c25:94de:a253
432c19:dd:d9:dd:c25:c25:94de:a254/1272c19:dd:d9:dd:c25:c25:94de:a255
442c19:dd:d9:dd:c25:c25:94de:a256/1272c19:dd:d9:dd:c25:c25:94de:a257
452c19:dd:d9:dd:c25:c25:94de:a258/1272c19:dd:d9:dd:c25:c25:94de:a259
462c19:dd:d9:dd:c25:c25:94de:a25a/1272c19:dd:d9:dd:c25:c25:94de:a25b
472c19:dd:d9:dd:c25:c25:94de:a25c/1272c19:dd:d9:dd:c25:c25:94de:a25d
482c19:dd:d9:dd:c25:c25:94de:a25e/1272c19:dd:d9:dd:c25:c25:94de:a25f
492c19:dd:d9:dd:c25:c25:94de:a260/1272c19:dd:d9:dd:c25:c25:94de:a261
502c19:dd:d9:dd:c25:c25:94de:a262/1272c19:dd:d9:dd:c25:c25:94de:a263
512c19:dd:d9:dd:c25:c25:94de:a264/1272c19:dd:d9:dd:c25:c25:94de:a265
522c19:dd:d9:dd:c25:c25:94de:a266/1272c19:dd:d9:dd:c25:c25:94de:a267
532c19:dd:d9:dd:c25:c25:94de:a268/1272c19:dd:d9:dd:c25:c25:94de:a269
542c19:dd:d9:dd:c25:c25:94de:a26a/1272c19:dd:d9:dd:c25:c25:94de:a26b
552c19:dd:d9:dd:c25:c25:94de:a26c/1272c19:dd:d9:dd:c25:c25:94de:a26d
562c19:dd:d9:dd:c25:c25:94de:a26e/1272c19:dd:d9:dd:c25:c25:94de:a26f
572c19:dd:d9:dd:c25:c25:94de:a270/1272c19:dd:d9:dd:c25:c25:94de:a271
582c19:dd:d9:dd:c25:c25:94de:a272/1272c19:dd:d9:dd:c25:c25:94de:a273
592c19:dd:d9:dd:c25:c25:94de:a274/1272c19:dd:d9:dd:c25:c25:94de:a275
602c19:dd:d9:dd:c25:c25:94de:a276/1272c19:dd:d9:dd:c25:c25:94de:a277
612c19:dd:d9:dd:c25:c25:94de:a278/1272c19:dd:d9:dd:c25:c25:94de:a279
622c19:dd:d9:dd:c25:c25:94de:a27a/1272c19:dd:d9:dd:c25:c25:94de:a27b
632c19:dd:d9:dd:c25:c25:94de:a27c/1272c19:dd:d9:dd:c25:c25:94de:a27d
642c19:dd:d9:dd:c25:c25:94de:a27e/1272c19:dd:d9:dd:c25:c25:94de:a27f
652c19:dd:d9:dd:c25:c25:94de:a280/1272c19:dd:d9:dd:c25:c25:94de:a281
662c19:dd:d9:dd:c25:c25:94de:a282/1272c19:dd:d9:dd:c25:c25:94de:a283
672c19:dd:d9:dd:c25:c25:94de:a284/1272c19:dd:d9:dd:c25:c25:94de:a285
682c19:dd:d9:dd:c25:c25:94de:a286/1272c19:dd:d9:dd:c25:c25:94de:a287
692c19:dd:d9:dd:c25:c25:94de:a288/1272c19:dd:d9:dd:c25:c25:94de:a289
702c19:dd:d9:dd:c25:c25:94de:a28a/1272c19:dd:d9:dd:c25:c25:94de:a28b
712c19:dd:d9:dd:c25:c25:94de:a28c/1272c19:dd:d9:dd:c25:c25:94de:a28d
722c19:dd:d9:dd:c25:c25:94de:a28e/1272c19:dd:d9:dd:c25:c25:94de:a28f
732c19:dd:d9:dd:c25:c25:94de:a290/1272c19:dd:d9:dd:c25:c25:94de:a291
742c19:dd:d9:dd:c25:c25:94de:a292/1272c19:dd:d9:dd:c25:c25:94de:a293
752c19:dd:d9:dd:c25:c25:94de:a294/1272c19:dd:d9:dd:c25:c25:94de:a295
762c19:dd:d9:dd:c25:c25:94de:a296/1272c19:dd:d9:dd:c25:c25:94de:a297
772c19:dd:d9:dd:c25:c25:94de:a298/1272c19:dd:d9:dd:c25:c25:94de:a299
782c19:dd:d9:dd:c25:c25:94de:a29a/1272c19:dd:d9:dd:c25:c25:94de:a29b
792c19:dd:d9:dd:c25:c25:94de:a29c/1272c19:dd:d9:dd:c25:c25:94de:a29d
802c19:dd:d9:dd:c25:c25:94de:a29e/1272c19:dd:d9:dd:c25:c25:94de:a29f
812c19:dd:d9:dd:c25:c25:94de:a2a0/1272c19:dd:d9:dd:c25:c25:94de:a2a1
822c19:dd:d9:dd:c25:c25:94de:a2a2/1272c19:dd:d9:dd:c25:c25:94de:a2a3
832c19:dd:d9:dd:c25:c25:94de:a2a4/1272c19:dd:d9:dd:c25:c25:94de:a2a5
842c19:dd:d9:dd:c25:c25:94de:a2a6/1272c19:dd:d9:dd:c25:c25:94de:a2a7
852c19:dd:d9:dd:c25:c25:94de:a2a8/1272c19:dd:d9:dd:c25:c25:94de:a2a9
862c19:dd:d9:dd:c25:c25:94de:a2aa/1272c19:dd:d9:dd:c25:c25:94de:a2ab
872c19:dd:d9:dd:c25:c25:94de:a2ac/1272c19:dd:d9:dd:c25:c25:94de:a2ad
882c19:dd:d9:dd:c25:c25:94de:a2ae/1272c19:dd:d9:dd:c25:c25:94de:a2af
892c19:dd:d9:dd:c25:c25:94de:a2b0/1272c19:dd:d9:dd:c25:c25:94de:a2b1
902c19:dd:d9:dd:c25:c25:94de:a2b2/1272c19:dd:d9:dd:c25:c25:94de:a2b3
912c19:dd:d9:dd:c25:c25:94de:a2b4/1272c19:dd:d9:dd:c25:c25:94de:a2b5
922c19:dd:d9:dd:c25:c25:94de:a2b6/1272c19:dd:d9:dd:c25:c25:94de:a2b7
932c19:dd:d9:dd:c25:c25:94de:a2b8/1272c19:dd:d9:dd:c25:c25:94de:a2b9
942c19:dd:d9:dd:c25:c25:94de:a2ba/1272c19:dd:d9:dd:c25:c25:94de:a2bb
952c19:dd:d9:dd:c25:c25:94de:a2bc/1272c19:dd:d9:dd:c25:c25:94de:a2bd
962c19:dd:d9:dd:c25:c25:94de:a2be/1272c19:dd:d9:dd:c25:c25:94de:a2bf
972c19:dd:d9:dd:c25:c25:94de:a2c0/1272c19:dd:d9:dd:c25:c25:94de:a2c1
982c19:dd:d9:dd:c25:c25:94de:a2c2/1272c19:dd:d9:dd:c25:c25:94de:a2c3
992c19:dd:d9:dd:c25:c25:94de:a2c4/1272c19:dd:d9:dd:c25:c25:94de:a2c5
1002c19:dd:d9:dd:c25:c25:94de:a2c6/1272c19:dd:d9:dd:c25:c25:94de:a2c7
1012c19:dd:d9:dd:c25:c25:94de:a2c8/1272c19:dd:d9:dd:c25:c25:94de:a2c9
1022c19:dd:d9:dd:c25:c25:94de:a2ca/1272c19:dd:d9:dd:c25:c25:94de:a2cb
1032c19:dd:d9:dd:c25:c25:94de:a2cc/1272c19:dd:d9:dd:c25:c25:94de:a2cd
1042c19:dd:d9:dd:c25:c25:94de:a2ce/1272c19:dd:d9:dd:c25:c25:94de:a2cf
1052c19:dd:d9:dd:c25:c25:94de:a2d0/1272c19:dd:d9:dd:c25:c25:94de:a2d1
1062c19:dd:d9:dd:c25:c25:94de:a2d2/1272c19:dd:d9:dd:c25:c25:94de:a2d3
1072c19:dd:d9:dd:c25:c25:94de:a2d4/1272c19:dd:d9:dd:c25:c25:94de:a2d5
1082c19:dd:d9:dd:c25:c25:94de:a2d6/1272c19:dd:d9:dd:c25:c25:94de:a2d7
1092c19:dd:d9:dd:c25:c25:94de:a2d8/1272c19:dd:d9:dd:c25:c25:94de:a2d9
1102c19:dd:d9:dd:c25:c25:94de:a2da/1272c19:dd:d9:dd:c25:c25:94de:a2db
1112c19:dd:d9:dd:c25:c25:94de:a2dc/1272c19:dd:d9:dd:c25:c25:94de:a2dd
1122c19:dd:d9:dd:c25:c25:94de:a2de/1272c19:dd:d9:dd:c25:c25:94de:a2df
1132c19:dd:d9:dd:c25:c25:94de:a2e0/1272c19:dd:d9:dd:c25:c25:94de:a2e1
1142c19:dd:d9:dd:c25:c25:94de:a2e2/1272c19:dd:d9:dd:c25:c25:94de:a2e3
1152c19:dd:d9:dd:c25:c25:94de:a2e4/1272c19:dd:d9:dd:c25:c25:94de:a2e5
1162c19:dd:d9:dd:c25:c25:94de:a2e6/1272c19:dd:d9:dd:c25:c25:94de:a2e7
1172c19:dd:d9:dd:c25:c25:94de:a2e8/1272c19:dd:d9:dd:c25:c25:94de:a2e9
1182c19:dd:d9:dd:c25:c25:94de:a2ea/1272c19:dd:d9:dd:c25:c25:94de:a2eb
1192c19:dd:d9:dd:c25:c25:94de:a2ec/1272c19:dd:d9:dd:c25:c25:94de:a2ed
1202c19:dd:d9:dd:c25:c25:94de:a2ee/1272c19:dd:d9:dd:c25:c25:94de:a2ef
1212c19:dd:d9:dd:c25:c25:94de:a2f0/1272c19:dd:d9:dd:c25:c25:94de:a2f1
1222c19:dd:d9:dd:c25:c25:94de:a2f2/1272c19:dd:d9:dd:c25:c25:94de:a2f3
1232c19:dd:d9:dd:c25:c25:94de:a2f4/1272c19:dd:d9:dd:c25:c25:94de:a2f5
1242c19:dd:d9:dd:c25:c25:94de:a2f6/1272c19:dd:d9:dd:c25:c25:94de:a2f7
1252c19:dd:d9:dd:c25:c25:94de:a2f8/1272c19:dd:d9:dd:c25:c25:94de:a2f9
1262c19:dd:d9:dd:c25:c25:94de:a2fa/1272c19:dd:d9:dd:c25:c25:94de:a2fb
1272c19:dd:d9:dd:c25:c25:94de:a2fc/1272c19:dd:d9:dd:c25:c25:94de:a2fd
1282c19:dd:d9:dd:c25:c25:94de:a2fe/1272c19:dd:d9:dd:c25:c25:94de:a2ff
1292c19:dd:d9:dd:c25:c25:94de:a300/1272c19:dd:d9:dd:c25:c25:94de:a301
1302c19:dd:d9:dd:c25:c25:94de:a302/1272c19:dd:d9:dd:c25:c25:94de:a303
1312c19:dd:d9:dd:c25:c25:94de:a304/1272c19:dd:d9:dd:c25:c25:94de:a305
1322c19:dd:d9:dd:c25:c25:94de:a306/1272c19:dd:d9:dd:c25:c25:94de:a307
1332c19:dd:d9:dd:c25:c25:94de:a308/1272c19:dd:d9:dd:c25:c25:94de:a309
1342c19:dd:d9:dd:c25:c25:94de:a30a/1272c19:dd:d9:dd:c25:c25:94de:a30b
1352c19:dd:d9:dd:c25:c25:94de:a30c/1272c19:dd:d9:dd:c25:c25:94de:a30d
1362c19:dd:d9:dd:c25:c25:94de:a30e/1272c19:dd:d9:dd:c25:c25:94de:a30f
1372c19:dd:d9:dd:c25:c25:94de:a310/1272c19:dd:d9:dd:c25:c25:94de:a311
1382c19:dd:d9:dd:c25:c25:94de:a312/1272c19:dd:d9:dd:c25:c25:94de:a313
1392c19:dd:d9:dd:c25:c25:94de:a314/1272c19:dd:d9:dd:c25:c25:94de:a315
1402c19:dd:d9:dd:c25:c25:94de:a316/1272c19:dd:d9:dd:c25:c25:94de:a317
1412c19:dd:d9:dd:c25:c25:94de:a318/1272c19:dd:d9:dd:c25:c25:94de:a319
1422c19:dd:d9:dd:c25:c25:94de:a31a/1272c19:dd:d9:dd:c25:c25:94de:a31b
1432c19:dd:d9:dd:c25:c25:94de:a31c/1272c19:dd:d9:dd:c25:c25:94de:a31d
1442c19:dd:d9:dd:c25:c25:94de:a31e/1272c19:dd:d9:dd:c25:c25:94de:a31f
1452c19:dd:d9:dd:c25:c25:94de:a320/1272c19:dd:d9:dd:c25:c25:94de:a321
1462c19:dd:d9:dd:c25:c25:94de:a322/1272c19:dd:d9:dd:c25:c25:94de:a323
1472c19:dd:d9:dd:c25:c25:94de:a324/1272c19:dd:d9:dd:c25:c25:94de:a325
1482c19:dd:d9:dd:c25:c25:94de:a326/1272c19:dd:d9:dd:c25:c25:94de:a327
1492c19:dd:d9:dd:c25:c25:94de:a328/1272c19:dd:d9:dd:c25:c25:94de:a329
1502c19:dd:d9:dd:c25:c25:94de:a32a/1272c19:dd:d9:dd:c25:c25:94de:a32b
1512c19:dd:d9:dd:c25:c25:94de:a32c/1272c19:dd:d9:dd:c25:c25:94de:a32d
1522c19:dd:d9:dd:c25:c25:94de:a32e/1272c19:dd:d9:dd:c25:c25:94de:a32f
1532c19:dd:d9:dd:c25:c25:94de:a330/1272c19:dd:d9:dd:c25:c25:94de:a331
1542c19:dd:d9:dd:c25:c25:94de:a332/1272c19:dd:d9:dd:c25:c25:94de:a333
1552c19:dd:d9:dd:c25:c25:94de:a334/1272c19:dd:d9:dd:c25:c25:94de:a335
1562c19:dd:d9:dd:c25:c25:94de:a336/1272c19:dd:d9:dd:c25:c25:94de:a337
1572c19:dd:d9:dd:c25:c25:94de:a338/1272c19:dd:d9:dd:c25:c25:94de:a339
1582c19:dd:d9:dd:c25:c25:94de:a33a/1272c19:dd:d9:dd:c25:c25:94de:a33b
1592c19:dd:d9:dd:c25:c25:94de:a33c/1272c19:dd:d9:dd:c25:c25:94de:a33d
1602c19:dd:d9:dd:c25:c25:94de:a33e/1272c19:dd:d9:dd:c25:c25:94de:a33f
1612c19:dd:d9:dd:c25:c25:94de:a340/1272c19:dd:d9:dd:c25:c25:94de:a341
1622c19:dd:d9:dd:c25:c25:94de:a342/1272c19:dd:d9:dd:c25:c25:94de:a343
1632c19:dd:d9:dd:c25:c25:94de:a344/1272c19:dd:d9:dd:c25:c25:94de:a345
1642c19:dd:d9:dd:c25:c25:94de:a346/1272c19:dd:d9:dd:c25:c25:94de:a347
1652c19:dd:d9:dd:c25:c25:94de:a348/1272c19:dd:d9:dd:c25:c25:94de:a349
1662c19:dd:d9:dd:c25:c25:94de:a34a/1272c19:dd:d9:dd:c25:c25:94de:a34b
1672c19:dd:d9:dd:c25:c25:94de:a34c/1272c19:dd:d9:dd:c25:c25:94de:a34d
1682c19:dd:d9:dd:c25:c25:94de:a34e/1272c19:dd:d9:dd:c25:c25:94de:a34f
1692c19:dd:d9:dd:c25:c25:94de:a350/1272c19:dd:d9:dd:c25:c25:94de:a351
1702c19:dd:d9:dd:c25:c25:94de:a352/1272c19:dd:d9:dd:c25:c25:94de:a353
1712c19:dd:d9:dd:c25:c25:94de:a354/1272c19:dd:d9:dd:c25:c25:94de:a355
1722c19:dd:d9:dd:c25:c25:94de:a356/1272c19:dd:d9:dd:c25:c25:94de:a357
1732c19:dd:d9:dd:c25:c25:94de:a358/1272c19:dd:d9:dd:c25:c25:94de:a359
1742c19:dd:d9:dd:c25:c25:94de:a35a/1272c19:dd:d9:dd:c25:c25:94de:a35b
1752c19:dd:d9:dd:c25:c25:94de:a35c/1272c19:dd:d9:dd:c25:c25:94de:a35d
1762c19:dd:d9:dd:c25:c25:94de:a35e/1272c19:dd:d9:dd:c25:c25:94de:a35f
1772c19:dd:d9:dd:c25:c25:94de:a360/1272c19:dd:d9:dd:c25:c25:94de:a361
1782c19:dd:d9:dd:c25:c25:94de:a362/1272c19:dd:d9:dd:c25:c25:94de:a363
1792c19:dd:d9:dd:c25:c25:94de:a364/1272c19:dd:d9:dd:c25:c25:94de:a365
1802c19:dd:d9:dd:c25:c25:94de:a366/1272c19:dd:d9:dd:c25:c25:94de:a367
1812c19:dd:d9:dd:c25:c25:94de:a368/1272c19:dd:d9:dd:c25:c25:94de:a369
1822c19:dd:d9:dd:c25:c25:94de:a36a/1272c19:dd:d9:dd:c25:c25:94de:a36b
1832c19:dd:d9:dd:c25:c25:94de:a36c/1272c19:dd:d9:dd:c25:c25:94de:a36d
1842c19:dd:d9:dd:c25:c25:94de:a36e/1272c19:dd:d9:dd:c25:c25:94de:a36f
1852c19:dd:d9:dd:c25:c25:94de:a370/1272c19:dd:d9:dd:c25:c25:94de:a371
1862c19:dd:d9:dd:c25:c25:94de:a372/1272c19:dd:d9:dd:c25:c25:94de:a373
1872c19:dd:d9:dd:c25:c25:94de:a374/1272c19:dd:d9:dd:c25:c25:94de:a375
1882c19:dd:d9:dd:c25:c25:94de:a376/1272c19:dd:d9:dd:c25:c25:94de:a377
1892c19:dd:d9:dd:c25:c25:94de:a378/1272c19:dd:d9:dd:c25:c25:94de:a379
1902c19:dd:d9:dd:c25:c25:94de:a37a/1272c19:dd:d9:dd:c25:c25:94de:a37b
1912c19:dd:d9:dd:c25:c25:94de:a37c/1272c19:dd:d9:dd:c25:c25:94de:a37d
1922c19:dd:d9:dd:c25:c25:94de:a37e/1272c19:dd:d9:dd:c25:c25:94de:a37f
1932c19:dd:d9:dd:c25:c25:94de:a380/1272c19:dd:d9:dd:c25:c25:94de:a381
1942c19:dd:d9:dd:c25:c25:94de:a382/1272c19:dd:d9:dd:c25:c25:94de:a383
1952c19:dd:d9:dd:c25:c25:94de:a384/1272c19:dd:d9:dd:c25:c25:94de:a385
1962c19:dd:d9:dd:c25:c25:94de:a386/1272c19:dd:d9:dd:c25:c25:94de:a387
1972c19:dd:d9:dd:c25:c25:94de:a388/1272c19:dd:d9:dd:c25:c25:94de:a389
1982c19:dd:d9:dd:c25:c25:94de:a38a/1272c19:dd:d9:dd:c25:c25:94de:a38b
1992c19:dd:d9:dd:c25:c25:94de:a38c/1272c19:dd:d9:dd:c25:c25:94de:a38d
2002c19:dd:d9:dd:c25:c25:94de:a38e/1272c19:dd:d9:dd:c25:c25:94de:a38f
2012c19:dd:d9:dd:c25:c25:94de:a390/1272c19:dd:d9:dd:c25:c25:94de:a391
2022c19:dd:d9:dd:c25:c25:94de:a392/1272c19:dd:d9:dd:c25:c25:94de:a393
2032c19:dd:d9:dd:c25:c25:94de:a394/1272c19:dd:d9:dd:c25:c25:94de:a395
2042c19:dd:d9:dd:c25:c25:94de:a396/1272c19:dd:d9:dd:c25:c25:94de:a397
2052c19:dd:d9:dd:c25:c25:94de:a398/1272c19:dd:d9:dd:c25:c25:94de:a399
2062c19:dd:d9:dd:c25:c25:94de:a39a/1272c19:dd:d9:dd:c25:c25:94de:a39b
2072c19:dd:d9:dd:c25:c25:94de:a39c/1272c19:dd:d9:dd:c25:c25:94de:a39d
2082c19:dd:d9:dd:c25:c25:94de:a39e/1272c19:dd:d9:dd:c25:c25:94de:a39f
2092c19:dd:d9:dd:c25:c25:94de:a3a0/1272c19:dd:d9:dd:c25:c25:94de:a3a1
2102c19:dd:d9:dd:c25:c25:94de:a3a2/1272c19:dd:d9:dd:c25:c25:94de:a3a3
2112c19:dd:d9:dd:c25:c25:94de:a3a4/1272c19:dd:d9:dd:c25:c25:94de:a3a5
2122c19:dd:d9:dd:c25:c25:94de:a3a6/1272c19:dd:d9:dd:c25:c25:94de:a3a7
2132c19:dd:d9:dd:c25:c25:94de:a3a8/1272c19:dd:d9:dd:c25:c25:94de:a3a9
2142c19:dd:d9:dd:c25:c25:94de:a3aa/1272c19:dd:d9:dd:c25:c25:94de:a3ab
2152c19:dd:d9:dd:c25:c25:94de:a3ac/1272c19:dd:d9:dd:c25:c25:94de:a3ad
2162c19:dd:d9:dd:c25:c25:94de:a3ae/1272c19:dd:d9:dd:c25:c25:94de:a3af
2172c19:dd:d9:dd:c25:c25:94de:a3b0/1272c19:dd:d9:dd:c25:c25:94de:a3b1
2182c19:dd:d9:dd:c25:c25:94de:a3b2/1272c19:dd:d9:dd:c25:c25:94de:a3b3
2192c19:dd:d9:dd:c25:c25:94de:a3b4/1272c19:dd:d9:dd:c25:c25:94de:a3b5
2202c19:dd:d9:dd:c25:c25:94de:a3b6/1272c19:dd:d9:dd:c25:c25:94de:a3b7
2212c19:dd:d9:dd:c25:c25:94de:a3b8/1272c19:dd:d9:dd:c25:c25:94de:a3b9
2222c19:dd:d9:dd:c25:c25:94de:a3ba/1272c19:dd:d9:dd:c25:c25:94de:a3bb
2232c19:dd:d9:dd:c25:c25:94de:a3bc/1272c19:dd:d9:dd:c25:c25:94de:a3bd
2242c19:dd:d9:dd:c25:c25:94de:a3be/1272c19:dd:d9:dd:c25:c25:94de:a3bf
2252c19:dd:d9:dd:c25:c25:94de:a3c0/1272c19:dd:d9:dd:c25:c25:94de:a3c1
2262c19:dd:d9:dd:c25:c25:94de:a3c2/1272c19:dd:d9:dd:c25:c25:94de:a3c3
2272c19:dd:d9:dd:c25:c25:94de:a3c4/1272c19:dd:d9:dd:c25:c25:94de:a3c5
2282c19:dd:d9:dd:c25:c25:94de:a3c6/1272c19:dd:d9:dd:c25:c25:94de:a3c7
2292c19:dd:d9:dd:c25:c25:94de:a3c8/1272c19:dd:d9:dd:c25:c25:94de:a3c9
2302c19:dd:d9:dd:c25:c25:94de:a3ca/1272c19:dd:d9:dd:c25:c25:94de:a3cb
2312c19:dd:d9:dd:c25:c25:94de:a3cc/1272c19:dd:d9:dd:c25:c25:94de:a3cd
2322c19:dd:d9:dd:c25:c25:94de:a3ce/1272c19:dd:d9:dd:c25:c25:94de:a3cf
2332c19:dd:d9:dd:c25:c25:94de:a3d0/1272c19:dd:d9:dd:c25:c25:94de:a3d1
2342c19:dd:d9:dd:c25:c25:94de:a3d2/1272c19:dd:d9:dd:c25:c25:94de:a3d3
2352c19:dd:d9:dd:c25:c25:94de:a3d4/1272c19:dd:d9:dd:c25:c25:94de:a3d5
2362c19:dd:d9:dd:c25:c25:94de:a3d6/1272c19:dd:d9:dd:c25:c25:94de:a3d7
2372c19:dd:d9:dd:c25:c25:94de:a3d8/1272c19:dd:d9:dd:c25:c25:94de:a3d9
2382c19:dd:d9:dd:c25:c25:94de:a3da/1272c19:dd:d9:dd:c25:c25:94de:a3db
2392c19:dd:d9:dd:c25:c25:94de:a3dc/1272c19:dd:d9:dd:c25:c25:94de:a3dd
2402c19:dd:d9:dd:c25:c25:94de:a3de/1272c19:dd:d9:dd:c25:c25:94de:a3df
2412c19:dd:d9:dd:c25:c25:94de:a3e0/1272c19:dd:d9:dd:c25:c25:94de:a3e1
2422c19:dd:d9:dd:c25:c25:94de:a3e2/1272c19:dd:d9:dd:c25:c25:94de:a3e3
2432c19:dd:d9:dd:c25:c25:94de:a3e4/1272c19:dd:d9:dd:c25:c25:94de:a3e5
2442c19:dd:d9:dd:c25:c25:94de:a3e6/1272c19:dd:d9:dd:c25:c25:94de:a3e7
2452c19:dd:d9:dd:c25:c25:94de:a3e8/1272c19:dd:d9:dd:c25:c25:94de:a3e9
2462c19:dd:d9:dd:c25:c25:94de:a3ea/1272c19:dd:d9:dd:c25:c25:94de:a3eb
2472c19:dd:d9:dd:c25:c25:94de:a3ec/1272c19:dd:d9:dd:c25:c25:94de:a3ed
2482c19:dd:d9:dd:c25:c25:94de:a3ee/1272c19:dd:d9:dd:c25:c25:94de:a3ef
2492c19:dd:d9:dd:c25:c25:94de:a3f0/1272c19:dd:d9:dd:c25:c25:94de:a3f1
2502c19:dd:d9:dd:c25:c25:94de:a3f2/1272c19:dd:d9:dd:c25:c25:94de:a3f3
2512c19:dd:d9:dd:c25:c25:94de:a3f4/1272c19:dd:d9:dd:c25:c25:94de:a3f5
2522c19:dd:d9:dd:c25:c25:94de:a3f6/1272c19:dd:d9:dd:c25:c25:94de:a3f7
2532c19:dd:d9:dd:c25:c25:94de:a3f8/1272c19:dd:d9:dd:c25:c25:94de:a3f9
2542c19:dd:d9:dd:c25:c25:94de:a3fa/1272c19:dd:d9:dd:c25:c25:94de:a3fb
2552c19:dd:d9:dd:c25:c25:94de:a3fc/1272c19:dd:d9:dd:c25:c25:94de:a3fd
2562c19:dd:d9:dd:c25:c25:94de:a3fe/1272c19:dd:d9:dd:c25:c25:94de:a3ff

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.