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:d600/119
First address
2c19:dd:d9:dd:c25:c25:94de:d600
Last address
2c19:dd:d9:dd:c25:c25:94de:d7ff
Addresses
512
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:d600
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
6.d.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
7.d.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:d600/119 makes 256 subnets of /127.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:d600/1272c19:dd:d9:dd:c25:c25:94de:d601
22c19:dd:d9:dd:c25:c25:94de:d602/1272c19:dd:d9:dd:c25:c25:94de:d603
32c19:dd:d9:dd:c25:c25:94de:d604/1272c19:dd:d9:dd:c25:c25:94de:d605
42c19:dd:d9:dd:c25:c25:94de:d606/1272c19:dd:d9:dd:c25:c25:94de:d607
52c19:dd:d9:dd:c25:c25:94de:d608/1272c19:dd:d9:dd:c25:c25:94de:d609
62c19:dd:d9:dd:c25:c25:94de:d60a/1272c19:dd:d9:dd:c25:c25:94de:d60b
72c19:dd:d9:dd:c25:c25:94de:d60c/1272c19:dd:d9:dd:c25:c25:94de:d60d
82c19:dd:d9:dd:c25:c25:94de:d60e/1272c19:dd:d9:dd:c25:c25:94de:d60f
92c19:dd:d9:dd:c25:c25:94de:d610/1272c19:dd:d9:dd:c25:c25:94de:d611
102c19:dd:d9:dd:c25:c25:94de:d612/1272c19:dd:d9:dd:c25:c25:94de:d613
112c19:dd:d9:dd:c25:c25:94de:d614/1272c19:dd:d9:dd:c25:c25:94de:d615
122c19:dd:d9:dd:c25:c25:94de:d616/1272c19:dd:d9:dd:c25:c25:94de:d617
132c19:dd:d9:dd:c25:c25:94de:d618/1272c19:dd:d9:dd:c25:c25:94de:d619
142c19:dd:d9:dd:c25:c25:94de:d61a/1272c19:dd:d9:dd:c25:c25:94de:d61b
152c19:dd:d9:dd:c25:c25:94de:d61c/1272c19:dd:d9:dd:c25:c25:94de:d61d
162c19:dd:d9:dd:c25:c25:94de:d61e/1272c19:dd:d9:dd:c25:c25:94de:d61f
172c19:dd:d9:dd:c25:c25:94de:d620/1272c19:dd:d9:dd:c25:c25:94de:d621
182c19:dd:d9:dd:c25:c25:94de:d622/1272c19:dd:d9:dd:c25:c25:94de:d623
192c19:dd:d9:dd:c25:c25:94de:d624/1272c19:dd:d9:dd:c25:c25:94de:d625
202c19:dd:d9:dd:c25:c25:94de:d626/1272c19:dd:d9:dd:c25:c25:94de:d627
212c19:dd:d9:dd:c25:c25:94de:d628/1272c19:dd:d9:dd:c25:c25:94de:d629
222c19:dd:d9:dd:c25:c25:94de:d62a/1272c19:dd:d9:dd:c25:c25:94de:d62b
232c19:dd:d9:dd:c25:c25:94de:d62c/1272c19:dd:d9:dd:c25:c25:94de:d62d
242c19:dd:d9:dd:c25:c25:94de:d62e/1272c19:dd:d9:dd:c25:c25:94de:d62f
252c19:dd:d9:dd:c25:c25:94de:d630/1272c19:dd:d9:dd:c25:c25:94de:d631
262c19:dd:d9:dd:c25:c25:94de:d632/1272c19:dd:d9:dd:c25:c25:94de:d633
272c19:dd:d9:dd:c25:c25:94de:d634/1272c19:dd:d9:dd:c25:c25:94de:d635
282c19:dd:d9:dd:c25:c25:94de:d636/1272c19:dd:d9:dd:c25:c25:94de:d637
292c19:dd:d9:dd:c25:c25:94de:d638/1272c19:dd:d9:dd:c25:c25:94de:d639
302c19:dd:d9:dd:c25:c25:94de:d63a/1272c19:dd:d9:dd:c25:c25:94de:d63b
312c19:dd:d9:dd:c25:c25:94de:d63c/1272c19:dd:d9:dd:c25:c25:94de:d63d
322c19:dd:d9:dd:c25:c25:94de:d63e/1272c19:dd:d9:dd:c25:c25:94de:d63f
332c19:dd:d9:dd:c25:c25:94de:d640/1272c19:dd:d9:dd:c25:c25:94de:d641
342c19:dd:d9:dd:c25:c25:94de:d642/1272c19:dd:d9:dd:c25:c25:94de:d643
352c19:dd:d9:dd:c25:c25:94de:d644/1272c19:dd:d9:dd:c25:c25:94de:d645
362c19:dd:d9:dd:c25:c25:94de:d646/1272c19:dd:d9:dd:c25:c25:94de:d647
372c19:dd:d9:dd:c25:c25:94de:d648/1272c19:dd:d9:dd:c25:c25:94de:d649
382c19:dd:d9:dd:c25:c25:94de:d64a/1272c19:dd:d9:dd:c25:c25:94de:d64b
392c19:dd:d9:dd:c25:c25:94de:d64c/1272c19:dd:d9:dd:c25:c25:94de:d64d
402c19:dd:d9:dd:c25:c25:94de:d64e/1272c19:dd:d9:dd:c25:c25:94de:d64f
412c19:dd:d9:dd:c25:c25:94de:d650/1272c19:dd:d9:dd:c25:c25:94de:d651
422c19:dd:d9:dd:c25:c25:94de:d652/1272c19:dd:d9:dd:c25:c25:94de:d653
432c19:dd:d9:dd:c25:c25:94de:d654/1272c19:dd:d9:dd:c25:c25:94de:d655
442c19:dd:d9:dd:c25:c25:94de:d656/1272c19:dd:d9:dd:c25:c25:94de:d657
452c19:dd:d9:dd:c25:c25:94de:d658/1272c19:dd:d9:dd:c25:c25:94de:d659
462c19:dd:d9:dd:c25:c25:94de:d65a/1272c19:dd:d9:dd:c25:c25:94de:d65b
472c19:dd:d9:dd:c25:c25:94de:d65c/1272c19:dd:d9:dd:c25:c25:94de:d65d
482c19:dd:d9:dd:c25:c25:94de:d65e/1272c19:dd:d9:dd:c25:c25:94de:d65f
492c19:dd:d9:dd:c25:c25:94de:d660/1272c19:dd:d9:dd:c25:c25:94de:d661
502c19:dd:d9:dd:c25:c25:94de:d662/1272c19:dd:d9:dd:c25:c25:94de:d663
512c19:dd:d9:dd:c25:c25:94de:d664/1272c19:dd:d9:dd:c25:c25:94de:d665
522c19:dd:d9:dd:c25:c25:94de:d666/1272c19:dd:d9:dd:c25:c25:94de:d667
532c19:dd:d9:dd:c25:c25:94de:d668/1272c19:dd:d9:dd:c25:c25:94de:d669
542c19:dd:d9:dd:c25:c25:94de:d66a/1272c19:dd:d9:dd:c25:c25:94de:d66b
552c19:dd:d9:dd:c25:c25:94de:d66c/1272c19:dd:d9:dd:c25:c25:94de:d66d
562c19:dd:d9:dd:c25:c25:94de:d66e/1272c19:dd:d9:dd:c25:c25:94de:d66f
572c19:dd:d9:dd:c25:c25:94de:d670/1272c19:dd:d9:dd:c25:c25:94de:d671
582c19:dd:d9:dd:c25:c25:94de:d672/1272c19:dd:d9:dd:c25:c25:94de:d673
592c19:dd:d9:dd:c25:c25:94de:d674/1272c19:dd:d9:dd:c25:c25:94de:d675
602c19:dd:d9:dd:c25:c25:94de:d676/1272c19:dd:d9:dd:c25:c25:94de:d677
612c19:dd:d9:dd:c25:c25:94de:d678/1272c19:dd:d9:dd:c25:c25:94de:d679
622c19:dd:d9:dd:c25:c25:94de:d67a/1272c19:dd:d9:dd:c25:c25:94de:d67b
632c19:dd:d9:dd:c25:c25:94de:d67c/1272c19:dd:d9:dd:c25:c25:94de:d67d
642c19:dd:d9:dd:c25:c25:94de:d67e/1272c19:dd:d9:dd:c25:c25:94de:d67f
652c19:dd:d9:dd:c25:c25:94de:d680/1272c19:dd:d9:dd:c25:c25:94de:d681
662c19:dd:d9:dd:c25:c25:94de:d682/1272c19:dd:d9:dd:c25:c25:94de:d683
672c19:dd:d9:dd:c25:c25:94de:d684/1272c19:dd:d9:dd:c25:c25:94de:d685
682c19:dd:d9:dd:c25:c25:94de:d686/1272c19:dd:d9:dd:c25:c25:94de:d687
692c19:dd:d9:dd:c25:c25:94de:d688/1272c19:dd:d9:dd:c25:c25:94de:d689
702c19:dd:d9:dd:c25:c25:94de:d68a/1272c19:dd:d9:dd:c25:c25:94de:d68b
712c19:dd:d9:dd:c25:c25:94de:d68c/1272c19:dd:d9:dd:c25:c25:94de:d68d
722c19:dd:d9:dd:c25:c25:94de:d68e/1272c19:dd:d9:dd:c25:c25:94de:d68f
732c19:dd:d9:dd:c25:c25:94de:d690/1272c19:dd:d9:dd:c25:c25:94de:d691
742c19:dd:d9:dd:c25:c25:94de:d692/1272c19:dd:d9:dd:c25:c25:94de:d693
752c19:dd:d9:dd:c25:c25:94de:d694/1272c19:dd:d9:dd:c25:c25:94de:d695
762c19:dd:d9:dd:c25:c25:94de:d696/1272c19:dd:d9:dd:c25:c25:94de:d697
772c19:dd:d9:dd:c25:c25:94de:d698/1272c19:dd:d9:dd:c25:c25:94de:d699
782c19:dd:d9:dd:c25:c25:94de:d69a/1272c19:dd:d9:dd:c25:c25:94de:d69b
792c19:dd:d9:dd:c25:c25:94de:d69c/1272c19:dd:d9:dd:c25:c25:94de:d69d
802c19:dd:d9:dd:c25:c25:94de:d69e/1272c19:dd:d9:dd:c25:c25:94de:d69f
812c19:dd:d9:dd:c25:c25:94de:d6a0/1272c19:dd:d9:dd:c25:c25:94de:d6a1
822c19:dd:d9:dd:c25:c25:94de:d6a2/1272c19:dd:d9:dd:c25:c25:94de:d6a3
832c19:dd:d9:dd:c25:c25:94de:d6a4/1272c19:dd:d9:dd:c25:c25:94de:d6a5
842c19:dd:d9:dd:c25:c25:94de:d6a6/1272c19:dd:d9:dd:c25:c25:94de:d6a7
852c19:dd:d9:dd:c25:c25:94de:d6a8/1272c19:dd:d9:dd:c25:c25:94de:d6a9
862c19:dd:d9:dd:c25:c25:94de:d6aa/1272c19:dd:d9:dd:c25:c25:94de:d6ab
872c19:dd:d9:dd:c25:c25:94de:d6ac/1272c19:dd:d9:dd:c25:c25:94de:d6ad
882c19:dd:d9:dd:c25:c25:94de:d6ae/1272c19:dd:d9:dd:c25:c25:94de:d6af
892c19:dd:d9:dd:c25:c25:94de:d6b0/1272c19:dd:d9:dd:c25:c25:94de:d6b1
902c19:dd:d9:dd:c25:c25:94de:d6b2/1272c19:dd:d9:dd:c25:c25:94de:d6b3
912c19:dd:d9:dd:c25:c25:94de:d6b4/1272c19:dd:d9:dd:c25:c25:94de:d6b5
922c19:dd:d9:dd:c25:c25:94de:d6b6/1272c19:dd:d9:dd:c25:c25:94de:d6b7
932c19:dd:d9:dd:c25:c25:94de:d6b8/1272c19:dd:d9:dd:c25:c25:94de:d6b9
942c19:dd:d9:dd:c25:c25:94de:d6ba/1272c19:dd:d9:dd:c25:c25:94de:d6bb
952c19:dd:d9:dd:c25:c25:94de:d6bc/1272c19:dd:d9:dd:c25:c25:94de:d6bd
962c19:dd:d9:dd:c25:c25:94de:d6be/1272c19:dd:d9:dd:c25:c25:94de:d6bf
972c19:dd:d9:dd:c25:c25:94de:d6c0/1272c19:dd:d9:dd:c25:c25:94de:d6c1
982c19:dd:d9:dd:c25:c25:94de:d6c2/1272c19:dd:d9:dd:c25:c25:94de:d6c3
992c19:dd:d9:dd:c25:c25:94de:d6c4/1272c19:dd:d9:dd:c25:c25:94de:d6c5
1002c19:dd:d9:dd:c25:c25:94de:d6c6/1272c19:dd:d9:dd:c25:c25:94de:d6c7
1012c19:dd:d9:dd:c25:c25:94de:d6c8/1272c19:dd:d9:dd:c25:c25:94de:d6c9
1022c19:dd:d9:dd:c25:c25:94de:d6ca/1272c19:dd:d9:dd:c25:c25:94de:d6cb
1032c19:dd:d9:dd:c25:c25:94de:d6cc/1272c19:dd:d9:dd:c25:c25:94de:d6cd
1042c19:dd:d9:dd:c25:c25:94de:d6ce/1272c19:dd:d9:dd:c25:c25:94de:d6cf
1052c19:dd:d9:dd:c25:c25:94de:d6d0/1272c19:dd:d9:dd:c25:c25:94de:d6d1
1062c19:dd:d9:dd:c25:c25:94de:d6d2/1272c19:dd:d9:dd:c25:c25:94de:d6d3
1072c19:dd:d9:dd:c25:c25:94de:d6d4/1272c19:dd:d9:dd:c25:c25:94de:d6d5
1082c19:dd:d9:dd:c25:c25:94de:d6d6/1272c19:dd:d9:dd:c25:c25:94de:d6d7
1092c19:dd:d9:dd:c25:c25:94de:d6d8/1272c19:dd:d9:dd:c25:c25:94de:d6d9
1102c19:dd:d9:dd:c25:c25:94de:d6da/1272c19:dd:d9:dd:c25:c25:94de:d6db
1112c19:dd:d9:dd:c25:c25:94de:d6dc/1272c19:dd:d9:dd:c25:c25:94de:d6dd
1122c19:dd:d9:dd:c25:c25:94de:d6de/1272c19:dd:d9:dd:c25:c25:94de:d6df
1132c19:dd:d9:dd:c25:c25:94de:d6e0/1272c19:dd:d9:dd:c25:c25:94de:d6e1
1142c19:dd:d9:dd:c25:c25:94de:d6e2/1272c19:dd:d9:dd:c25:c25:94de:d6e3
1152c19:dd:d9:dd:c25:c25:94de:d6e4/1272c19:dd:d9:dd:c25:c25:94de:d6e5
1162c19:dd:d9:dd:c25:c25:94de:d6e6/1272c19:dd:d9:dd:c25:c25:94de:d6e7
1172c19:dd:d9:dd:c25:c25:94de:d6e8/1272c19:dd:d9:dd:c25:c25:94de:d6e9
1182c19:dd:d9:dd:c25:c25:94de:d6ea/1272c19:dd:d9:dd:c25:c25:94de:d6eb
1192c19:dd:d9:dd:c25:c25:94de:d6ec/1272c19:dd:d9:dd:c25:c25:94de:d6ed
1202c19:dd:d9:dd:c25:c25:94de:d6ee/1272c19:dd:d9:dd:c25:c25:94de:d6ef
1212c19:dd:d9:dd:c25:c25:94de:d6f0/1272c19:dd:d9:dd:c25:c25:94de:d6f1
1222c19:dd:d9:dd:c25:c25:94de:d6f2/1272c19:dd:d9:dd:c25:c25:94de:d6f3
1232c19:dd:d9:dd:c25:c25:94de:d6f4/1272c19:dd:d9:dd:c25:c25:94de:d6f5
1242c19:dd:d9:dd:c25:c25:94de:d6f6/1272c19:dd:d9:dd:c25:c25:94de:d6f7
1252c19:dd:d9:dd:c25:c25:94de:d6f8/1272c19:dd:d9:dd:c25:c25:94de:d6f9
1262c19:dd:d9:dd:c25:c25:94de:d6fa/1272c19:dd:d9:dd:c25:c25:94de:d6fb
1272c19:dd:d9:dd:c25:c25:94de:d6fc/1272c19:dd:d9:dd:c25:c25:94de:d6fd
1282c19:dd:d9:dd:c25:c25:94de:d6fe/1272c19:dd:d9:dd:c25:c25:94de:d6ff
1292c19:dd:d9:dd:c25:c25:94de:d700/1272c19:dd:d9:dd:c25:c25:94de:d701
1302c19:dd:d9:dd:c25:c25:94de:d702/1272c19:dd:d9:dd:c25:c25:94de:d703
1312c19:dd:d9:dd:c25:c25:94de:d704/1272c19:dd:d9:dd:c25:c25:94de:d705
1322c19:dd:d9:dd:c25:c25:94de:d706/1272c19:dd:d9:dd:c25:c25:94de:d707
1332c19:dd:d9:dd:c25:c25:94de:d708/1272c19:dd:d9:dd:c25:c25:94de:d709
1342c19:dd:d9:dd:c25:c25:94de:d70a/1272c19:dd:d9:dd:c25:c25:94de:d70b
1352c19:dd:d9:dd:c25:c25:94de:d70c/1272c19:dd:d9:dd:c25:c25:94de:d70d
1362c19:dd:d9:dd:c25:c25:94de:d70e/1272c19:dd:d9:dd:c25:c25:94de:d70f
1372c19:dd:d9:dd:c25:c25:94de:d710/1272c19:dd:d9:dd:c25:c25:94de:d711
1382c19:dd:d9:dd:c25:c25:94de:d712/1272c19:dd:d9:dd:c25:c25:94de:d713
1392c19:dd:d9:dd:c25:c25:94de:d714/1272c19:dd:d9:dd:c25:c25:94de:d715
1402c19:dd:d9:dd:c25:c25:94de:d716/1272c19:dd:d9:dd:c25:c25:94de:d717
1412c19:dd:d9:dd:c25:c25:94de:d718/1272c19:dd:d9:dd:c25:c25:94de:d719
1422c19:dd:d9:dd:c25:c25:94de:d71a/1272c19:dd:d9:dd:c25:c25:94de:d71b
1432c19:dd:d9:dd:c25:c25:94de:d71c/1272c19:dd:d9:dd:c25:c25:94de:d71d
1442c19:dd:d9:dd:c25:c25:94de:d71e/1272c19:dd:d9:dd:c25:c25:94de:d71f
1452c19:dd:d9:dd:c25:c25:94de:d720/1272c19:dd:d9:dd:c25:c25:94de:d721
1462c19:dd:d9:dd:c25:c25:94de:d722/1272c19:dd:d9:dd:c25:c25:94de:d723
1472c19:dd:d9:dd:c25:c25:94de:d724/1272c19:dd:d9:dd:c25:c25:94de:d725
1482c19:dd:d9:dd:c25:c25:94de:d726/1272c19:dd:d9:dd:c25:c25:94de:d727
1492c19:dd:d9:dd:c25:c25:94de:d728/1272c19:dd:d9:dd:c25:c25:94de:d729
1502c19:dd:d9:dd:c25:c25:94de:d72a/1272c19:dd:d9:dd:c25:c25:94de:d72b
1512c19:dd:d9:dd:c25:c25:94de:d72c/1272c19:dd:d9:dd:c25:c25:94de:d72d
1522c19:dd:d9:dd:c25:c25:94de:d72e/1272c19:dd:d9:dd:c25:c25:94de:d72f
1532c19:dd:d9:dd:c25:c25:94de:d730/1272c19:dd:d9:dd:c25:c25:94de:d731
1542c19:dd:d9:dd:c25:c25:94de:d732/1272c19:dd:d9:dd:c25:c25:94de:d733
1552c19:dd:d9:dd:c25:c25:94de:d734/1272c19:dd:d9:dd:c25:c25:94de:d735
1562c19:dd:d9:dd:c25:c25:94de:d736/1272c19:dd:d9:dd:c25:c25:94de:d737
1572c19:dd:d9:dd:c25:c25:94de:d738/1272c19:dd:d9:dd:c25:c25:94de:d739
1582c19:dd:d9:dd:c25:c25:94de:d73a/1272c19:dd:d9:dd:c25:c25:94de:d73b
1592c19:dd:d9:dd:c25:c25:94de:d73c/1272c19:dd:d9:dd:c25:c25:94de:d73d
1602c19:dd:d9:dd:c25:c25:94de:d73e/1272c19:dd:d9:dd:c25:c25:94de:d73f
1612c19:dd:d9:dd:c25:c25:94de:d740/1272c19:dd:d9:dd:c25:c25:94de:d741
1622c19:dd:d9:dd:c25:c25:94de:d742/1272c19:dd:d9:dd:c25:c25:94de:d743
1632c19:dd:d9:dd:c25:c25:94de:d744/1272c19:dd:d9:dd:c25:c25:94de:d745
1642c19:dd:d9:dd:c25:c25:94de:d746/1272c19:dd:d9:dd:c25:c25:94de:d747
1652c19:dd:d9:dd:c25:c25:94de:d748/1272c19:dd:d9:dd:c25:c25:94de:d749
1662c19:dd:d9:dd:c25:c25:94de:d74a/1272c19:dd:d9:dd:c25:c25:94de:d74b
1672c19:dd:d9:dd:c25:c25:94de:d74c/1272c19:dd:d9:dd:c25:c25:94de:d74d
1682c19:dd:d9:dd:c25:c25:94de:d74e/1272c19:dd:d9:dd:c25:c25:94de:d74f
1692c19:dd:d9:dd:c25:c25:94de:d750/1272c19:dd:d9:dd:c25:c25:94de:d751
1702c19:dd:d9:dd:c25:c25:94de:d752/1272c19:dd:d9:dd:c25:c25:94de:d753
1712c19:dd:d9:dd:c25:c25:94de:d754/1272c19:dd:d9:dd:c25:c25:94de:d755
1722c19:dd:d9:dd:c25:c25:94de:d756/1272c19:dd:d9:dd:c25:c25:94de:d757
1732c19:dd:d9:dd:c25:c25:94de:d758/1272c19:dd:d9:dd:c25:c25:94de:d759
1742c19:dd:d9:dd:c25:c25:94de:d75a/1272c19:dd:d9:dd:c25:c25:94de:d75b
1752c19:dd:d9:dd:c25:c25:94de:d75c/1272c19:dd:d9:dd:c25:c25:94de:d75d
1762c19:dd:d9:dd:c25:c25:94de:d75e/1272c19:dd:d9:dd:c25:c25:94de:d75f
1772c19:dd:d9:dd:c25:c25:94de:d760/1272c19:dd:d9:dd:c25:c25:94de:d761
1782c19:dd:d9:dd:c25:c25:94de:d762/1272c19:dd:d9:dd:c25:c25:94de:d763
1792c19:dd:d9:dd:c25:c25:94de:d764/1272c19:dd:d9:dd:c25:c25:94de:d765
1802c19:dd:d9:dd:c25:c25:94de:d766/1272c19:dd:d9:dd:c25:c25:94de:d767
1812c19:dd:d9:dd:c25:c25:94de:d768/1272c19:dd:d9:dd:c25:c25:94de:d769
1822c19:dd:d9:dd:c25:c25:94de:d76a/1272c19:dd:d9:dd:c25:c25:94de:d76b
1832c19:dd:d9:dd:c25:c25:94de:d76c/1272c19:dd:d9:dd:c25:c25:94de:d76d
1842c19:dd:d9:dd:c25:c25:94de:d76e/1272c19:dd:d9:dd:c25:c25:94de:d76f
1852c19:dd:d9:dd:c25:c25:94de:d770/1272c19:dd:d9:dd:c25:c25:94de:d771
1862c19:dd:d9:dd:c25:c25:94de:d772/1272c19:dd:d9:dd:c25:c25:94de:d773
1872c19:dd:d9:dd:c25:c25:94de:d774/1272c19:dd:d9:dd:c25:c25:94de:d775
1882c19:dd:d9:dd:c25:c25:94de:d776/1272c19:dd:d9:dd:c25:c25:94de:d777
1892c19:dd:d9:dd:c25:c25:94de:d778/1272c19:dd:d9:dd:c25:c25:94de:d779
1902c19:dd:d9:dd:c25:c25:94de:d77a/1272c19:dd:d9:dd:c25:c25:94de:d77b
1912c19:dd:d9:dd:c25:c25:94de:d77c/1272c19:dd:d9:dd:c25:c25:94de:d77d
1922c19:dd:d9:dd:c25:c25:94de:d77e/1272c19:dd:d9:dd:c25:c25:94de:d77f
1932c19:dd:d9:dd:c25:c25:94de:d780/1272c19:dd:d9:dd:c25:c25:94de:d781
1942c19:dd:d9:dd:c25:c25:94de:d782/1272c19:dd:d9:dd:c25:c25:94de:d783
1952c19:dd:d9:dd:c25:c25:94de:d784/1272c19:dd:d9:dd:c25:c25:94de:d785
1962c19:dd:d9:dd:c25:c25:94de:d786/1272c19:dd:d9:dd:c25:c25:94de:d787
1972c19:dd:d9:dd:c25:c25:94de:d788/1272c19:dd:d9:dd:c25:c25:94de:d789
1982c19:dd:d9:dd:c25:c25:94de:d78a/1272c19:dd:d9:dd:c25:c25:94de:d78b
1992c19:dd:d9:dd:c25:c25:94de:d78c/1272c19:dd:d9:dd:c25:c25:94de:d78d
2002c19:dd:d9:dd:c25:c25:94de:d78e/1272c19:dd:d9:dd:c25:c25:94de:d78f
2012c19:dd:d9:dd:c25:c25:94de:d790/1272c19:dd:d9:dd:c25:c25:94de:d791
2022c19:dd:d9:dd:c25:c25:94de:d792/1272c19:dd:d9:dd:c25:c25:94de:d793
2032c19:dd:d9:dd:c25:c25:94de:d794/1272c19:dd:d9:dd:c25:c25:94de:d795
2042c19:dd:d9:dd:c25:c25:94de:d796/1272c19:dd:d9:dd:c25:c25:94de:d797
2052c19:dd:d9:dd:c25:c25:94de:d798/1272c19:dd:d9:dd:c25:c25:94de:d799
2062c19:dd:d9:dd:c25:c25:94de:d79a/1272c19:dd:d9:dd:c25:c25:94de:d79b
2072c19:dd:d9:dd:c25:c25:94de:d79c/1272c19:dd:d9:dd:c25:c25:94de:d79d
2082c19:dd:d9:dd:c25:c25:94de:d79e/1272c19:dd:d9:dd:c25:c25:94de:d79f
2092c19:dd:d9:dd:c25:c25:94de:d7a0/1272c19:dd:d9:dd:c25:c25:94de:d7a1
2102c19:dd:d9:dd:c25:c25:94de:d7a2/1272c19:dd:d9:dd:c25:c25:94de:d7a3
2112c19:dd:d9:dd:c25:c25:94de:d7a4/1272c19:dd:d9:dd:c25:c25:94de:d7a5
2122c19:dd:d9:dd:c25:c25:94de:d7a6/1272c19:dd:d9:dd:c25:c25:94de:d7a7
2132c19:dd:d9:dd:c25:c25:94de:d7a8/1272c19:dd:d9:dd:c25:c25:94de:d7a9
2142c19:dd:d9:dd:c25:c25:94de:d7aa/1272c19:dd:d9:dd:c25:c25:94de:d7ab
2152c19:dd:d9:dd:c25:c25:94de:d7ac/1272c19:dd:d9:dd:c25:c25:94de:d7ad
2162c19:dd:d9:dd:c25:c25:94de:d7ae/1272c19:dd:d9:dd:c25:c25:94de:d7af
2172c19:dd:d9:dd:c25:c25:94de:d7b0/1272c19:dd:d9:dd:c25:c25:94de:d7b1
2182c19:dd:d9:dd:c25:c25:94de:d7b2/1272c19:dd:d9:dd:c25:c25:94de:d7b3
2192c19:dd:d9:dd:c25:c25:94de:d7b4/1272c19:dd:d9:dd:c25:c25:94de:d7b5
2202c19:dd:d9:dd:c25:c25:94de:d7b6/1272c19:dd:d9:dd:c25:c25:94de:d7b7
2212c19:dd:d9:dd:c25:c25:94de:d7b8/1272c19:dd:d9:dd:c25:c25:94de:d7b9
2222c19:dd:d9:dd:c25:c25:94de:d7ba/1272c19:dd:d9:dd:c25:c25:94de:d7bb
2232c19:dd:d9:dd:c25:c25:94de:d7bc/1272c19:dd:d9:dd:c25:c25:94de:d7bd
2242c19:dd:d9:dd:c25:c25:94de:d7be/1272c19:dd:d9:dd:c25:c25:94de:d7bf
2252c19:dd:d9:dd:c25:c25:94de:d7c0/1272c19:dd:d9:dd:c25:c25:94de:d7c1
2262c19:dd:d9:dd:c25:c25:94de:d7c2/1272c19:dd:d9:dd:c25:c25:94de:d7c3
2272c19:dd:d9:dd:c25:c25:94de:d7c4/1272c19:dd:d9:dd:c25:c25:94de:d7c5
2282c19:dd:d9:dd:c25:c25:94de:d7c6/1272c19:dd:d9:dd:c25:c25:94de:d7c7
2292c19:dd:d9:dd:c25:c25:94de:d7c8/1272c19:dd:d9:dd:c25:c25:94de:d7c9
2302c19:dd:d9:dd:c25:c25:94de:d7ca/1272c19:dd:d9:dd:c25:c25:94de:d7cb
2312c19:dd:d9:dd:c25:c25:94de:d7cc/1272c19:dd:d9:dd:c25:c25:94de:d7cd
2322c19:dd:d9:dd:c25:c25:94de:d7ce/1272c19:dd:d9:dd:c25:c25:94de:d7cf
2332c19:dd:d9:dd:c25:c25:94de:d7d0/1272c19:dd:d9:dd:c25:c25:94de:d7d1
2342c19:dd:d9:dd:c25:c25:94de:d7d2/1272c19:dd:d9:dd:c25:c25:94de:d7d3
2352c19:dd:d9:dd:c25:c25:94de:d7d4/1272c19:dd:d9:dd:c25:c25:94de:d7d5
2362c19:dd:d9:dd:c25:c25:94de:d7d6/1272c19:dd:d9:dd:c25:c25:94de:d7d7
2372c19:dd:d9:dd:c25:c25:94de:d7d8/1272c19:dd:d9:dd:c25:c25:94de:d7d9
2382c19:dd:d9:dd:c25:c25:94de:d7da/1272c19:dd:d9:dd:c25:c25:94de:d7db
2392c19:dd:d9:dd:c25:c25:94de:d7dc/1272c19:dd:d9:dd:c25:c25:94de:d7dd
2402c19:dd:d9:dd:c25:c25:94de:d7de/1272c19:dd:d9:dd:c25:c25:94de:d7df
2412c19:dd:d9:dd:c25:c25:94de:d7e0/1272c19:dd:d9:dd:c25:c25:94de:d7e1
2422c19:dd:d9:dd:c25:c25:94de:d7e2/1272c19:dd:d9:dd:c25:c25:94de:d7e3
2432c19:dd:d9:dd:c25:c25:94de:d7e4/1272c19:dd:d9:dd:c25:c25:94de:d7e5
2442c19:dd:d9:dd:c25:c25:94de:d7e6/1272c19:dd:d9:dd:c25:c25:94de:d7e7
2452c19:dd:d9:dd:c25:c25:94de:d7e8/1272c19:dd:d9:dd:c25:c25:94de:d7e9
2462c19:dd:d9:dd:c25:c25:94de:d7ea/1272c19:dd:d9:dd:c25:c25:94de:d7eb
2472c19:dd:d9:dd:c25:c25:94de:d7ec/1272c19:dd:d9:dd:c25:c25:94de:d7ed
2482c19:dd:d9:dd:c25:c25:94de:d7ee/1272c19:dd:d9:dd:c25:c25:94de:d7ef
2492c19:dd:d9:dd:c25:c25:94de:d7f0/1272c19:dd:d9:dd:c25:c25:94de:d7f1
2502c19:dd:d9:dd:c25:c25:94de:d7f2/1272c19:dd:d9:dd:c25:c25:94de:d7f3
2512c19:dd:d9:dd:c25:c25:94de:d7f4/1272c19:dd:d9:dd:c25:c25:94de:d7f5
2522c19:dd:d9:dd:c25:c25:94de:d7f6/1272c19:dd:d9:dd:c25:c25:94de:d7f7
2532c19:dd:d9:dd:c25:c25:94de:d7f8/1272c19:dd:d9:dd:c25:c25:94de:d7f9
2542c19:dd:d9:dd:c25:c25:94de:d7fa/1272c19:dd:d9:dd:c25:c25:94de:d7fb
2552c19:dd:d9:dd:c25:c25:94de:d7fc/1272c19:dd:d9:dd:c25:c25:94de:d7fd
2562c19:dd:d9:dd:c25:c25:94de:d7fe/1272c19:dd:d9:dd:c25:c25:94de:d7ff

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.