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:c00a:d400/119
First address
2c19:dd:d9:dd:c25:c25:c00a:d400
Last address
2c19:dd:d9:dd:c25:c25:c00a:d5ff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:c00a:d400
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
4.d.a.0.0.c.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
5.d.a.0.0.c.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/128
/120 (2)/121 (4)/122 (8)/123 (16)/124 (32)/127 (256)/128 (512)

2c19:dd:d9:dd:c25:c25:c00a:d400/119 makes 512 subnets of /128; the first 256 are listed.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:c00a:d400/1282c19:dd:d9:dd:c25:c25:c00a:d400
22c19:dd:d9:dd:c25:c25:c00a:d401/1282c19:dd:d9:dd:c25:c25:c00a:d401
32c19:dd:d9:dd:c25:c25:c00a:d402/1282c19:dd:d9:dd:c25:c25:c00a:d402
42c19:dd:d9:dd:c25:c25:c00a:d403/1282c19:dd:d9:dd:c25:c25:c00a:d403
52c19:dd:d9:dd:c25:c25:c00a:d404/1282c19:dd:d9:dd:c25:c25:c00a:d404
62c19:dd:d9:dd:c25:c25:c00a:d405/1282c19:dd:d9:dd:c25:c25:c00a:d405
72c19:dd:d9:dd:c25:c25:c00a:d406/1282c19:dd:d9:dd:c25:c25:c00a:d406
82c19:dd:d9:dd:c25:c25:c00a:d407/1282c19:dd:d9:dd:c25:c25:c00a:d407
92c19:dd:d9:dd:c25:c25:c00a:d408/1282c19:dd:d9:dd:c25:c25:c00a:d408
102c19:dd:d9:dd:c25:c25:c00a:d409/1282c19:dd:d9:dd:c25:c25:c00a:d409
112c19:dd:d9:dd:c25:c25:c00a:d40a/1282c19:dd:d9:dd:c25:c25:c00a:d40a
122c19:dd:d9:dd:c25:c25:c00a:d40b/1282c19:dd:d9:dd:c25:c25:c00a:d40b
132c19:dd:d9:dd:c25:c25:c00a:d40c/1282c19:dd:d9:dd:c25:c25:c00a:d40c
142c19:dd:d9:dd:c25:c25:c00a:d40d/1282c19:dd:d9:dd:c25:c25:c00a:d40d
152c19:dd:d9:dd:c25:c25:c00a:d40e/1282c19:dd:d9:dd:c25:c25:c00a:d40e
162c19:dd:d9:dd:c25:c25:c00a:d40f/1282c19:dd:d9:dd:c25:c25:c00a:d40f
172c19:dd:d9:dd:c25:c25:c00a:d410/1282c19:dd:d9:dd:c25:c25:c00a:d410
182c19:dd:d9:dd:c25:c25:c00a:d411/1282c19:dd:d9:dd:c25:c25:c00a:d411
192c19:dd:d9:dd:c25:c25:c00a:d412/1282c19:dd:d9:dd:c25:c25:c00a:d412
202c19:dd:d9:dd:c25:c25:c00a:d413/1282c19:dd:d9:dd:c25:c25:c00a:d413
212c19:dd:d9:dd:c25:c25:c00a:d414/1282c19:dd:d9:dd:c25:c25:c00a:d414
222c19:dd:d9:dd:c25:c25:c00a:d415/1282c19:dd:d9:dd:c25:c25:c00a:d415
232c19:dd:d9:dd:c25:c25:c00a:d416/1282c19:dd:d9:dd:c25:c25:c00a:d416
242c19:dd:d9:dd:c25:c25:c00a:d417/1282c19:dd:d9:dd:c25:c25:c00a:d417
252c19:dd:d9:dd:c25:c25:c00a:d418/1282c19:dd:d9:dd:c25:c25:c00a:d418
262c19:dd:d9:dd:c25:c25:c00a:d419/1282c19:dd:d9:dd:c25:c25:c00a:d419
272c19:dd:d9:dd:c25:c25:c00a:d41a/1282c19:dd:d9:dd:c25:c25:c00a:d41a
282c19:dd:d9:dd:c25:c25:c00a:d41b/1282c19:dd:d9:dd:c25:c25:c00a:d41b
292c19:dd:d9:dd:c25:c25:c00a:d41c/1282c19:dd:d9:dd:c25:c25:c00a:d41c
302c19:dd:d9:dd:c25:c25:c00a:d41d/1282c19:dd:d9:dd:c25:c25:c00a:d41d
312c19:dd:d9:dd:c25:c25:c00a:d41e/1282c19:dd:d9:dd:c25:c25:c00a:d41e
322c19:dd:d9:dd:c25:c25:c00a:d41f/1282c19:dd:d9:dd:c25:c25:c00a:d41f
332c19:dd:d9:dd:c25:c25:c00a:d420/1282c19:dd:d9:dd:c25:c25:c00a:d420
342c19:dd:d9:dd:c25:c25:c00a:d421/1282c19:dd:d9:dd:c25:c25:c00a:d421
352c19:dd:d9:dd:c25:c25:c00a:d422/1282c19:dd:d9:dd:c25:c25:c00a:d422
362c19:dd:d9:dd:c25:c25:c00a:d423/1282c19:dd:d9:dd:c25:c25:c00a:d423
372c19:dd:d9:dd:c25:c25:c00a:d424/1282c19:dd:d9:dd:c25:c25:c00a:d424
382c19:dd:d9:dd:c25:c25:c00a:d425/1282c19:dd:d9:dd:c25:c25:c00a:d425
392c19:dd:d9:dd:c25:c25:c00a:d426/1282c19:dd:d9:dd:c25:c25:c00a:d426
402c19:dd:d9:dd:c25:c25:c00a:d427/1282c19:dd:d9:dd:c25:c25:c00a:d427
412c19:dd:d9:dd:c25:c25:c00a:d428/1282c19:dd:d9:dd:c25:c25:c00a:d428
422c19:dd:d9:dd:c25:c25:c00a:d429/1282c19:dd:d9:dd:c25:c25:c00a:d429
432c19:dd:d9:dd:c25:c25:c00a:d42a/1282c19:dd:d9:dd:c25:c25:c00a:d42a
442c19:dd:d9:dd:c25:c25:c00a:d42b/1282c19:dd:d9:dd:c25:c25:c00a:d42b
452c19:dd:d9:dd:c25:c25:c00a:d42c/1282c19:dd:d9:dd:c25:c25:c00a:d42c
462c19:dd:d9:dd:c25:c25:c00a:d42d/1282c19:dd:d9:dd:c25:c25:c00a:d42d
472c19:dd:d9:dd:c25:c25:c00a:d42e/1282c19:dd:d9:dd:c25:c25:c00a:d42e
482c19:dd:d9:dd:c25:c25:c00a:d42f/1282c19:dd:d9:dd:c25:c25:c00a:d42f
492c19:dd:d9:dd:c25:c25:c00a:d430/1282c19:dd:d9:dd:c25:c25:c00a:d430
502c19:dd:d9:dd:c25:c25:c00a:d431/1282c19:dd:d9:dd:c25:c25:c00a:d431
512c19:dd:d9:dd:c25:c25:c00a:d432/1282c19:dd:d9:dd:c25:c25:c00a:d432
522c19:dd:d9:dd:c25:c25:c00a:d433/1282c19:dd:d9:dd:c25:c25:c00a:d433
532c19:dd:d9:dd:c25:c25:c00a:d434/1282c19:dd:d9:dd:c25:c25:c00a:d434
542c19:dd:d9:dd:c25:c25:c00a:d435/1282c19:dd:d9:dd:c25:c25:c00a:d435
552c19:dd:d9:dd:c25:c25:c00a:d436/1282c19:dd:d9:dd:c25:c25:c00a:d436
562c19:dd:d9:dd:c25:c25:c00a:d437/1282c19:dd:d9:dd:c25:c25:c00a:d437
572c19:dd:d9:dd:c25:c25:c00a:d438/1282c19:dd:d9:dd:c25:c25:c00a:d438
582c19:dd:d9:dd:c25:c25:c00a:d439/1282c19:dd:d9:dd:c25:c25:c00a:d439
592c19:dd:d9:dd:c25:c25:c00a:d43a/1282c19:dd:d9:dd:c25:c25:c00a:d43a
602c19:dd:d9:dd:c25:c25:c00a:d43b/1282c19:dd:d9:dd:c25:c25:c00a:d43b
612c19:dd:d9:dd:c25:c25:c00a:d43c/1282c19:dd:d9:dd:c25:c25:c00a:d43c
622c19:dd:d9:dd:c25:c25:c00a:d43d/1282c19:dd:d9:dd:c25:c25:c00a:d43d
632c19:dd:d9:dd:c25:c25:c00a:d43e/1282c19:dd:d9:dd:c25:c25:c00a:d43e
642c19:dd:d9:dd:c25:c25:c00a:d43f/1282c19:dd:d9:dd:c25:c25:c00a:d43f
652c19:dd:d9:dd:c25:c25:c00a:d440/1282c19:dd:d9:dd:c25:c25:c00a:d440
662c19:dd:d9:dd:c25:c25:c00a:d441/1282c19:dd:d9:dd:c25:c25:c00a:d441
672c19:dd:d9:dd:c25:c25:c00a:d442/1282c19:dd:d9:dd:c25:c25:c00a:d442
682c19:dd:d9:dd:c25:c25:c00a:d443/1282c19:dd:d9:dd:c25:c25:c00a:d443
692c19:dd:d9:dd:c25:c25:c00a:d444/1282c19:dd:d9:dd:c25:c25:c00a:d444
702c19:dd:d9:dd:c25:c25:c00a:d445/1282c19:dd:d9:dd:c25:c25:c00a:d445
712c19:dd:d9:dd:c25:c25:c00a:d446/1282c19:dd:d9:dd:c25:c25:c00a:d446
722c19:dd:d9:dd:c25:c25:c00a:d447/1282c19:dd:d9:dd:c25:c25:c00a:d447
732c19:dd:d9:dd:c25:c25:c00a:d448/1282c19:dd:d9:dd:c25:c25:c00a:d448
742c19:dd:d9:dd:c25:c25:c00a:d449/1282c19:dd:d9:dd:c25:c25:c00a:d449
752c19:dd:d9:dd:c25:c25:c00a:d44a/1282c19:dd:d9:dd:c25:c25:c00a:d44a
762c19:dd:d9:dd:c25:c25:c00a:d44b/1282c19:dd:d9:dd:c25:c25:c00a:d44b
772c19:dd:d9:dd:c25:c25:c00a:d44c/1282c19:dd:d9:dd:c25:c25:c00a:d44c
782c19:dd:d9:dd:c25:c25:c00a:d44d/1282c19:dd:d9:dd:c25:c25:c00a:d44d
792c19:dd:d9:dd:c25:c25:c00a:d44e/1282c19:dd:d9:dd:c25:c25:c00a:d44e
802c19:dd:d9:dd:c25:c25:c00a:d44f/1282c19:dd:d9:dd:c25:c25:c00a:d44f
812c19:dd:d9:dd:c25:c25:c00a:d450/1282c19:dd:d9:dd:c25:c25:c00a:d450
822c19:dd:d9:dd:c25:c25:c00a:d451/1282c19:dd:d9:dd:c25:c25:c00a:d451
832c19:dd:d9:dd:c25:c25:c00a:d452/1282c19:dd:d9:dd:c25:c25:c00a:d452
842c19:dd:d9:dd:c25:c25:c00a:d453/1282c19:dd:d9:dd:c25:c25:c00a:d453
852c19:dd:d9:dd:c25:c25:c00a:d454/1282c19:dd:d9:dd:c25:c25:c00a:d454
862c19:dd:d9:dd:c25:c25:c00a:d455/1282c19:dd:d9:dd:c25:c25:c00a:d455
872c19:dd:d9:dd:c25:c25:c00a:d456/1282c19:dd:d9:dd:c25:c25:c00a:d456
882c19:dd:d9:dd:c25:c25:c00a:d457/1282c19:dd:d9:dd:c25:c25:c00a:d457
892c19:dd:d9:dd:c25:c25:c00a:d458/1282c19:dd:d9:dd:c25:c25:c00a:d458
902c19:dd:d9:dd:c25:c25:c00a:d459/1282c19:dd:d9:dd:c25:c25:c00a:d459
912c19:dd:d9:dd:c25:c25:c00a:d45a/1282c19:dd:d9:dd:c25:c25:c00a:d45a
922c19:dd:d9:dd:c25:c25:c00a:d45b/1282c19:dd:d9:dd:c25:c25:c00a:d45b
932c19:dd:d9:dd:c25:c25:c00a:d45c/1282c19:dd:d9:dd:c25:c25:c00a:d45c
942c19:dd:d9:dd:c25:c25:c00a:d45d/1282c19:dd:d9:dd:c25:c25:c00a:d45d
952c19:dd:d9:dd:c25:c25:c00a:d45e/1282c19:dd:d9:dd:c25:c25:c00a:d45e
962c19:dd:d9:dd:c25:c25:c00a:d45f/1282c19:dd:d9:dd:c25:c25:c00a:d45f
972c19:dd:d9:dd:c25:c25:c00a:d460/1282c19:dd:d9:dd:c25:c25:c00a:d460
982c19:dd:d9:dd:c25:c25:c00a:d461/1282c19:dd:d9:dd:c25:c25:c00a:d461
992c19:dd:d9:dd:c25:c25:c00a:d462/1282c19:dd:d9:dd:c25:c25:c00a:d462
1002c19:dd:d9:dd:c25:c25:c00a:d463/1282c19:dd:d9:dd:c25:c25:c00a:d463
1012c19:dd:d9:dd:c25:c25:c00a:d464/1282c19:dd:d9:dd:c25:c25:c00a:d464
1022c19:dd:d9:dd:c25:c25:c00a:d465/1282c19:dd:d9:dd:c25:c25:c00a:d465
1032c19:dd:d9:dd:c25:c25:c00a:d466/1282c19:dd:d9:dd:c25:c25:c00a:d466
1042c19:dd:d9:dd:c25:c25:c00a:d467/1282c19:dd:d9:dd:c25:c25:c00a:d467
1052c19:dd:d9:dd:c25:c25:c00a:d468/1282c19:dd:d9:dd:c25:c25:c00a:d468
1062c19:dd:d9:dd:c25:c25:c00a:d469/1282c19:dd:d9:dd:c25:c25:c00a:d469
1072c19:dd:d9:dd:c25:c25:c00a:d46a/1282c19:dd:d9:dd:c25:c25:c00a:d46a
1082c19:dd:d9:dd:c25:c25:c00a:d46b/1282c19:dd:d9:dd:c25:c25:c00a:d46b
1092c19:dd:d9:dd:c25:c25:c00a:d46c/1282c19:dd:d9:dd:c25:c25:c00a:d46c
1102c19:dd:d9:dd:c25:c25:c00a:d46d/1282c19:dd:d9:dd:c25:c25:c00a:d46d
1112c19:dd:d9:dd:c25:c25:c00a:d46e/1282c19:dd:d9:dd:c25:c25:c00a:d46e
1122c19:dd:d9:dd:c25:c25:c00a:d46f/1282c19:dd:d9:dd:c25:c25:c00a:d46f
1132c19:dd:d9:dd:c25:c25:c00a:d470/1282c19:dd:d9:dd:c25:c25:c00a:d470
1142c19:dd:d9:dd:c25:c25:c00a:d471/1282c19:dd:d9:dd:c25:c25:c00a:d471
1152c19:dd:d9:dd:c25:c25:c00a:d472/1282c19:dd:d9:dd:c25:c25:c00a:d472
1162c19:dd:d9:dd:c25:c25:c00a:d473/1282c19:dd:d9:dd:c25:c25:c00a:d473
1172c19:dd:d9:dd:c25:c25:c00a:d474/1282c19:dd:d9:dd:c25:c25:c00a:d474
1182c19:dd:d9:dd:c25:c25:c00a:d475/1282c19:dd:d9:dd:c25:c25:c00a:d475
1192c19:dd:d9:dd:c25:c25:c00a:d476/1282c19:dd:d9:dd:c25:c25:c00a:d476
1202c19:dd:d9:dd:c25:c25:c00a:d477/1282c19:dd:d9:dd:c25:c25:c00a:d477
1212c19:dd:d9:dd:c25:c25:c00a:d478/1282c19:dd:d9:dd:c25:c25:c00a:d478
1222c19:dd:d9:dd:c25:c25:c00a:d479/1282c19:dd:d9:dd:c25:c25:c00a:d479
1232c19:dd:d9:dd:c25:c25:c00a:d47a/1282c19:dd:d9:dd:c25:c25:c00a:d47a
1242c19:dd:d9:dd:c25:c25:c00a:d47b/1282c19:dd:d9:dd:c25:c25:c00a:d47b
1252c19:dd:d9:dd:c25:c25:c00a:d47c/1282c19:dd:d9:dd:c25:c25:c00a:d47c
1262c19:dd:d9:dd:c25:c25:c00a:d47d/1282c19:dd:d9:dd:c25:c25:c00a:d47d
1272c19:dd:d9:dd:c25:c25:c00a:d47e/1282c19:dd:d9:dd:c25:c25:c00a:d47e
1282c19:dd:d9:dd:c25:c25:c00a:d47f/1282c19:dd:d9:dd:c25:c25:c00a:d47f
1292c19:dd:d9:dd:c25:c25:c00a:d480/1282c19:dd:d9:dd:c25:c25:c00a:d480
1302c19:dd:d9:dd:c25:c25:c00a:d481/1282c19:dd:d9:dd:c25:c25:c00a:d481
1312c19:dd:d9:dd:c25:c25:c00a:d482/1282c19:dd:d9:dd:c25:c25:c00a:d482
1322c19:dd:d9:dd:c25:c25:c00a:d483/1282c19:dd:d9:dd:c25:c25:c00a:d483
1332c19:dd:d9:dd:c25:c25:c00a:d484/1282c19:dd:d9:dd:c25:c25:c00a:d484
1342c19:dd:d9:dd:c25:c25:c00a:d485/1282c19:dd:d9:dd:c25:c25:c00a:d485
1352c19:dd:d9:dd:c25:c25:c00a:d486/1282c19:dd:d9:dd:c25:c25:c00a:d486
1362c19:dd:d9:dd:c25:c25:c00a:d487/1282c19:dd:d9:dd:c25:c25:c00a:d487
1372c19:dd:d9:dd:c25:c25:c00a:d488/1282c19:dd:d9:dd:c25:c25:c00a:d488
1382c19:dd:d9:dd:c25:c25:c00a:d489/1282c19:dd:d9:dd:c25:c25:c00a:d489
1392c19:dd:d9:dd:c25:c25:c00a:d48a/1282c19:dd:d9:dd:c25:c25:c00a:d48a
1402c19:dd:d9:dd:c25:c25:c00a:d48b/1282c19:dd:d9:dd:c25:c25:c00a:d48b
1412c19:dd:d9:dd:c25:c25:c00a:d48c/1282c19:dd:d9:dd:c25:c25:c00a:d48c
1422c19:dd:d9:dd:c25:c25:c00a:d48d/1282c19:dd:d9:dd:c25:c25:c00a:d48d
1432c19:dd:d9:dd:c25:c25:c00a:d48e/1282c19:dd:d9:dd:c25:c25:c00a:d48e
1442c19:dd:d9:dd:c25:c25:c00a:d48f/1282c19:dd:d9:dd:c25:c25:c00a:d48f
1452c19:dd:d9:dd:c25:c25:c00a:d490/1282c19:dd:d9:dd:c25:c25:c00a:d490
1462c19:dd:d9:dd:c25:c25:c00a:d491/1282c19:dd:d9:dd:c25:c25:c00a:d491
1472c19:dd:d9:dd:c25:c25:c00a:d492/1282c19:dd:d9:dd:c25:c25:c00a:d492
1482c19:dd:d9:dd:c25:c25:c00a:d493/1282c19:dd:d9:dd:c25:c25:c00a:d493
1492c19:dd:d9:dd:c25:c25:c00a:d494/1282c19:dd:d9:dd:c25:c25:c00a:d494
1502c19:dd:d9:dd:c25:c25:c00a:d495/1282c19:dd:d9:dd:c25:c25:c00a:d495
1512c19:dd:d9:dd:c25:c25:c00a:d496/1282c19:dd:d9:dd:c25:c25:c00a:d496
1522c19:dd:d9:dd:c25:c25:c00a:d497/1282c19:dd:d9:dd:c25:c25:c00a:d497
1532c19:dd:d9:dd:c25:c25:c00a:d498/1282c19:dd:d9:dd:c25:c25:c00a:d498
1542c19:dd:d9:dd:c25:c25:c00a:d499/1282c19:dd:d9:dd:c25:c25:c00a:d499
1552c19:dd:d9:dd:c25:c25:c00a:d49a/1282c19:dd:d9:dd:c25:c25:c00a:d49a
1562c19:dd:d9:dd:c25:c25:c00a:d49b/1282c19:dd:d9:dd:c25:c25:c00a:d49b
1572c19:dd:d9:dd:c25:c25:c00a:d49c/1282c19:dd:d9:dd:c25:c25:c00a:d49c
1582c19:dd:d9:dd:c25:c25:c00a:d49d/1282c19:dd:d9:dd:c25:c25:c00a:d49d
1592c19:dd:d9:dd:c25:c25:c00a:d49e/1282c19:dd:d9:dd:c25:c25:c00a:d49e
1602c19:dd:d9:dd:c25:c25:c00a:d49f/1282c19:dd:d9:dd:c25:c25:c00a:d49f
1612c19:dd:d9:dd:c25:c25:c00a:d4a0/1282c19:dd:d9:dd:c25:c25:c00a:d4a0
1622c19:dd:d9:dd:c25:c25:c00a:d4a1/1282c19:dd:d9:dd:c25:c25:c00a:d4a1
1632c19:dd:d9:dd:c25:c25:c00a:d4a2/1282c19:dd:d9:dd:c25:c25:c00a:d4a2
1642c19:dd:d9:dd:c25:c25:c00a:d4a3/1282c19:dd:d9:dd:c25:c25:c00a:d4a3
1652c19:dd:d9:dd:c25:c25:c00a:d4a4/1282c19:dd:d9:dd:c25:c25:c00a:d4a4
1662c19:dd:d9:dd:c25:c25:c00a:d4a5/1282c19:dd:d9:dd:c25:c25:c00a:d4a5
1672c19:dd:d9:dd:c25:c25:c00a:d4a6/1282c19:dd:d9:dd:c25:c25:c00a:d4a6
1682c19:dd:d9:dd:c25:c25:c00a:d4a7/1282c19:dd:d9:dd:c25:c25:c00a:d4a7
1692c19:dd:d9:dd:c25:c25:c00a:d4a8/1282c19:dd:d9:dd:c25:c25:c00a:d4a8
1702c19:dd:d9:dd:c25:c25:c00a:d4a9/1282c19:dd:d9:dd:c25:c25:c00a:d4a9
1712c19:dd:d9:dd:c25:c25:c00a:d4aa/1282c19:dd:d9:dd:c25:c25:c00a:d4aa
1722c19:dd:d9:dd:c25:c25:c00a:d4ab/1282c19:dd:d9:dd:c25:c25:c00a:d4ab
1732c19:dd:d9:dd:c25:c25:c00a:d4ac/1282c19:dd:d9:dd:c25:c25:c00a:d4ac
1742c19:dd:d9:dd:c25:c25:c00a:d4ad/1282c19:dd:d9:dd:c25:c25:c00a:d4ad
1752c19:dd:d9:dd:c25:c25:c00a:d4ae/1282c19:dd:d9:dd:c25:c25:c00a:d4ae
1762c19:dd:d9:dd:c25:c25:c00a:d4af/1282c19:dd:d9:dd:c25:c25:c00a:d4af
1772c19:dd:d9:dd:c25:c25:c00a:d4b0/1282c19:dd:d9:dd:c25:c25:c00a:d4b0
1782c19:dd:d9:dd:c25:c25:c00a:d4b1/1282c19:dd:d9:dd:c25:c25:c00a:d4b1
1792c19:dd:d9:dd:c25:c25:c00a:d4b2/1282c19:dd:d9:dd:c25:c25:c00a:d4b2
1802c19:dd:d9:dd:c25:c25:c00a:d4b3/1282c19:dd:d9:dd:c25:c25:c00a:d4b3
1812c19:dd:d9:dd:c25:c25:c00a:d4b4/1282c19:dd:d9:dd:c25:c25:c00a:d4b4
1822c19:dd:d9:dd:c25:c25:c00a:d4b5/1282c19:dd:d9:dd:c25:c25:c00a:d4b5
1832c19:dd:d9:dd:c25:c25:c00a:d4b6/1282c19:dd:d9:dd:c25:c25:c00a:d4b6
1842c19:dd:d9:dd:c25:c25:c00a:d4b7/1282c19:dd:d9:dd:c25:c25:c00a:d4b7
1852c19:dd:d9:dd:c25:c25:c00a:d4b8/1282c19:dd:d9:dd:c25:c25:c00a:d4b8
1862c19:dd:d9:dd:c25:c25:c00a:d4b9/1282c19:dd:d9:dd:c25:c25:c00a:d4b9
1872c19:dd:d9:dd:c25:c25:c00a:d4ba/1282c19:dd:d9:dd:c25:c25:c00a:d4ba
1882c19:dd:d9:dd:c25:c25:c00a:d4bb/1282c19:dd:d9:dd:c25:c25:c00a:d4bb
1892c19:dd:d9:dd:c25:c25:c00a:d4bc/1282c19:dd:d9:dd:c25:c25:c00a:d4bc
1902c19:dd:d9:dd:c25:c25:c00a:d4bd/1282c19:dd:d9:dd:c25:c25:c00a:d4bd
1912c19:dd:d9:dd:c25:c25:c00a:d4be/1282c19:dd:d9:dd:c25:c25:c00a:d4be
1922c19:dd:d9:dd:c25:c25:c00a:d4bf/1282c19:dd:d9:dd:c25:c25:c00a:d4bf
1932c19:dd:d9:dd:c25:c25:c00a:d4c0/1282c19:dd:d9:dd:c25:c25:c00a:d4c0
1942c19:dd:d9:dd:c25:c25:c00a:d4c1/1282c19:dd:d9:dd:c25:c25:c00a:d4c1
1952c19:dd:d9:dd:c25:c25:c00a:d4c2/1282c19:dd:d9:dd:c25:c25:c00a:d4c2
1962c19:dd:d9:dd:c25:c25:c00a:d4c3/1282c19:dd:d9:dd:c25:c25:c00a:d4c3
1972c19:dd:d9:dd:c25:c25:c00a:d4c4/1282c19:dd:d9:dd:c25:c25:c00a:d4c4
1982c19:dd:d9:dd:c25:c25:c00a:d4c5/1282c19:dd:d9:dd:c25:c25:c00a:d4c5
1992c19:dd:d9:dd:c25:c25:c00a:d4c6/1282c19:dd:d9:dd:c25:c25:c00a:d4c6
2002c19:dd:d9:dd:c25:c25:c00a:d4c7/1282c19:dd:d9:dd:c25:c25:c00a:d4c7
2012c19:dd:d9:dd:c25:c25:c00a:d4c8/1282c19:dd:d9:dd:c25:c25:c00a:d4c8
2022c19:dd:d9:dd:c25:c25:c00a:d4c9/1282c19:dd:d9:dd:c25:c25:c00a:d4c9
2032c19:dd:d9:dd:c25:c25:c00a:d4ca/1282c19:dd:d9:dd:c25:c25:c00a:d4ca
2042c19:dd:d9:dd:c25:c25:c00a:d4cb/1282c19:dd:d9:dd:c25:c25:c00a:d4cb
2052c19:dd:d9:dd:c25:c25:c00a:d4cc/1282c19:dd:d9:dd:c25:c25:c00a:d4cc
2062c19:dd:d9:dd:c25:c25:c00a:d4cd/1282c19:dd:d9:dd:c25:c25:c00a:d4cd
2072c19:dd:d9:dd:c25:c25:c00a:d4ce/1282c19:dd:d9:dd:c25:c25:c00a:d4ce
2082c19:dd:d9:dd:c25:c25:c00a:d4cf/1282c19:dd:d9:dd:c25:c25:c00a:d4cf
2092c19:dd:d9:dd:c25:c25:c00a:d4d0/1282c19:dd:d9:dd:c25:c25:c00a:d4d0
2102c19:dd:d9:dd:c25:c25:c00a:d4d1/1282c19:dd:d9:dd:c25:c25:c00a:d4d1
2112c19:dd:d9:dd:c25:c25:c00a:d4d2/1282c19:dd:d9:dd:c25:c25:c00a:d4d2
2122c19:dd:d9:dd:c25:c25:c00a:d4d3/1282c19:dd:d9:dd:c25:c25:c00a:d4d3
2132c19:dd:d9:dd:c25:c25:c00a:d4d4/1282c19:dd:d9:dd:c25:c25:c00a:d4d4
2142c19:dd:d9:dd:c25:c25:c00a:d4d5/1282c19:dd:d9:dd:c25:c25:c00a:d4d5
2152c19:dd:d9:dd:c25:c25:c00a:d4d6/1282c19:dd:d9:dd:c25:c25:c00a:d4d6
2162c19:dd:d9:dd:c25:c25:c00a:d4d7/1282c19:dd:d9:dd:c25:c25:c00a:d4d7
2172c19:dd:d9:dd:c25:c25:c00a:d4d8/1282c19:dd:d9:dd:c25:c25:c00a:d4d8
2182c19:dd:d9:dd:c25:c25:c00a:d4d9/1282c19:dd:d9:dd:c25:c25:c00a:d4d9
2192c19:dd:d9:dd:c25:c25:c00a:d4da/1282c19:dd:d9:dd:c25:c25:c00a:d4da
2202c19:dd:d9:dd:c25:c25:c00a:d4db/1282c19:dd:d9:dd:c25:c25:c00a:d4db
2212c19:dd:d9:dd:c25:c25:c00a:d4dc/1282c19:dd:d9:dd:c25:c25:c00a:d4dc
2222c19:dd:d9:dd:c25:c25:c00a:d4dd/1282c19:dd:d9:dd:c25:c25:c00a:d4dd
2232c19:dd:d9:dd:c25:c25:c00a:d4de/1282c19:dd:d9:dd:c25:c25:c00a:d4de
2242c19:dd:d9:dd:c25:c25:c00a:d4df/1282c19:dd:d9:dd:c25:c25:c00a:d4df
2252c19:dd:d9:dd:c25:c25:c00a:d4e0/1282c19:dd:d9:dd:c25:c25:c00a:d4e0
2262c19:dd:d9:dd:c25:c25:c00a:d4e1/1282c19:dd:d9:dd:c25:c25:c00a:d4e1
2272c19:dd:d9:dd:c25:c25:c00a:d4e2/1282c19:dd:d9:dd:c25:c25:c00a:d4e2
2282c19:dd:d9:dd:c25:c25:c00a:d4e3/1282c19:dd:d9:dd:c25:c25:c00a:d4e3
2292c19:dd:d9:dd:c25:c25:c00a:d4e4/1282c19:dd:d9:dd:c25:c25:c00a:d4e4
2302c19:dd:d9:dd:c25:c25:c00a:d4e5/1282c19:dd:d9:dd:c25:c25:c00a:d4e5
2312c19:dd:d9:dd:c25:c25:c00a:d4e6/1282c19:dd:d9:dd:c25:c25:c00a:d4e6
2322c19:dd:d9:dd:c25:c25:c00a:d4e7/1282c19:dd:d9:dd:c25:c25:c00a:d4e7
2332c19:dd:d9:dd:c25:c25:c00a:d4e8/1282c19:dd:d9:dd:c25:c25:c00a:d4e8
2342c19:dd:d9:dd:c25:c25:c00a:d4e9/1282c19:dd:d9:dd:c25:c25:c00a:d4e9
2352c19:dd:d9:dd:c25:c25:c00a:d4ea/1282c19:dd:d9:dd:c25:c25:c00a:d4ea
2362c19:dd:d9:dd:c25:c25:c00a:d4eb/1282c19:dd:d9:dd:c25:c25:c00a:d4eb
2372c19:dd:d9:dd:c25:c25:c00a:d4ec/1282c19:dd:d9:dd:c25:c25:c00a:d4ec
2382c19:dd:d9:dd:c25:c25:c00a:d4ed/1282c19:dd:d9:dd:c25:c25:c00a:d4ed
2392c19:dd:d9:dd:c25:c25:c00a:d4ee/1282c19:dd:d9:dd:c25:c25:c00a:d4ee
2402c19:dd:d9:dd:c25:c25:c00a:d4ef/1282c19:dd:d9:dd:c25:c25:c00a:d4ef
2412c19:dd:d9:dd:c25:c25:c00a:d4f0/1282c19:dd:d9:dd:c25:c25:c00a:d4f0
2422c19:dd:d9:dd:c25:c25:c00a:d4f1/1282c19:dd:d9:dd:c25:c25:c00a:d4f1
2432c19:dd:d9:dd:c25:c25:c00a:d4f2/1282c19:dd:d9:dd:c25:c25:c00a:d4f2
2442c19:dd:d9:dd:c25:c25:c00a:d4f3/1282c19:dd:d9:dd:c25:c25:c00a:d4f3
2452c19:dd:d9:dd:c25:c25:c00a:d4f4/1282c19:dd:d9:dd:c25:c25:c00a:d4f4
2462c19:dd:d9:dd:c25:c25:c00a:d4f5/1282c19:dd:d9:dd:c25:c25:c00a:d4f5
2472c19:dd:d9:dd:c25:c25:c00a:d4f6/1282c19:dd:d9:dd:c25:c25:c00a:d4f6
2482c19:dd:d9:dd:c25:c25:c00a:d4f7/1282c19:dd:d9:dd:c25:c25:c00a:d4f7
2492c19:dd:d9:dd:c25:c25:c00a:d4f8/1282c19:dd:d9:dd:c25:c25:c00a:d4f8
2502c19:dd:d9:dd:c25:c25:c00a:d4f9/1282c19:dd:d9:dd:c25:c25:c00a:d4f9
2512c19:dd:d9:dd:c25:c25:c00a:d4fa/1282c19:dd:d9:dd:c25:c25:c00a:d4fa
2522c19:dd:d9:dd:c25:c25:c00a:d4fb/1282c19:dd:d9:dd:c25:c25:c00a:d4fb
2532c19:dd:d9:dd:c25:c25:c00a:d4fc/1282c19:dd:d9:dd:c25:c25:c00a:d4fc
2542c19:dd:d9:dd:c25:c25:c00a:d4fd/1282c19:dd:d9:dd:c25:c25:c00a:d4fd
2552c19:dd:d9:dd:c25:c25:c00a:d4fe/1282c19:dd:d9:dd:c25:c25:c00a:d4fe
2562c19:dd:d9:dd:c25:c25:c00a:d4ff/1282c19:dd:d9:dd:c25:c25:c00a:d4ff

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.