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:4700/120
First address
2c19:dd:d9:dd:c25:c25:94de:4700
Last address
2c19:dd:d9:dd:c25:c25:94de:47ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:4700
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
7.4.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:4700/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:4700/1282c19:dd:d9:dd:c25:c25:94de:4700
22c19:dd:d9:dd:c25:c25:94de:4701/1282c19:dd:d9:dd:c25:c25:94de:4701
32c19:dd:d9:dd:c25:c25:94de:4702/1282c19:dd:d9:dd:c25:c25:94de:4702
42c19:dd:d9:dd:c25:c25:94de:4703/1282c19:dd:d9:dd:c25:c25:94de:4703
52c19:dd:d9:dd:c25:c25:94de:4704/1282c19:dd:d9:dd:c25:c25:94de:4704
62c19:dd:d9:dd:c25:c25:94de:4705/1282c19:dd:d9:dd:c25:c25:94de:4705
72c19:dd:d9:dd:c25:c25:94de:4706/1282c19:dd:d9:dd:c25:c25:94de:4706
82c19:dd:d9:dd:c25:c25:94de:4707/1282c19:dd:d9:dd:c25:c25:94de:4707
92c19:dd:d9:dd:c25:c25:94de:4708/1282c19:dd:d9:dd:c25:c25:94de:4708
102c19:dd:d9:dd:c25:c25:94de:4709/1282c19:dd:d9:dd:c25:c25:94de:4709
112c19:dd:d9:dd:c25:c25:94de:470a/1282c19:dd:d9:dd:c25:c25:94de:470a
122c19:dd:d9:dd:c25:c25:94de:470b/1282c19:dd:d9:dd:c25:c25:94de:470b
132c19:dd:d9:dd:c25:c25:94de:470c/1282c19:dd:d9:dd:c25:c25:94de:470c
142c19:dd:d9:dd:c25:c25:94de:470d/1282c19:dd:d9:dd:c25:c25:94de:470d
152c19:dd:d9:dd:c25:c25:94de:470e/1282c19:dd:d9:dd:c25:c25:94de:470e
162c19:dd:d9:dd:c25:c25:94de:470f/1282c19:dd:d9:dd:c25:c25:94de:470f
172c19:dd:d9:dd:c25:c25:94de:4710/1282c19:dd:d9:dd:c25:c25:94de:4710
182c19:dd:d9:dd:c25:c25:94de:4711/1282c19:dd:d9:dd:c25:c25:94de:4711
192c19:dd:d9:dd:c25:c25:94de:4712/1282c19:dd:d9:dd:c25:c25:94de:4712
202c19:dd:d9:dd:c25:c25:94de:4713/1282c19:dd:d9:dd:c25:c25:94de:4713
212c19:dd:d9:dd:c25:c25:94de:4714/1282c19:dd:d9:dd:c25:c25:94de:4714
222c19:dd:d9:dd:c25:c25:94de:4715/1282c19:dd:d9:dd:c25:c25:94de:4715
232c19:dd:d9:dd:c25:c25:94de:4716/1282c19:dd:d9:dd:c25:c25:94de:4716
242c19:dd:d9:dd:c25:c25:94de:4717/1282c19:dd:d9:dd:c25:c25:94de:4717
252c19:dd:d9:dd:c25:c25:94de:4718/1282c19:dd:d9:dd:c25:c25:94de:4718
262c19:dd:d9:dd:c25:c25:94de:4719/1282c19:dd:d9:dd:c25:c25:94de:4719
272c19:dd:d9:dd:c25:c25:94de:471a/1282c19:dd:d9:dd:c25:c25:94de:471a
282c19:dd:d9:dd:c25:c25:94de:471b/1282c19:dd:d9:dd:c25:c25:94de:471b
292c19:dd:d9:dd:c25:c25:94de:471c/1282c19:dd:d9:dd:c25:c25:94de:471c
302c19:dd:d9:dd:c25:c25:94de:471d/1282c19:dd:d9:dd:c25:c25:94de:471d
312c19:dd:d9:dd:c25:c25:94de:471e/1282c19:dd:d9:dd:c25:c25:94de:471e
322c19:dd:d9:dd:c25:c25:94de:471f/1282c19:dd:d9:dd:c25:c25:94de:471f
332c19:dd:d9:dd:c25:c25:94de:4720/1282c19:dd:d9:dd:c25:c25:94de:4720
342c19:dd:d9:dd:c25:c25:94de:4721/1282c19:dd:d9:dd:c25:c25:94de:4721
352c19:dd:d9:dd:c25:c25:94de:4722/1282c19:dd:d9:dd:c25:c25:94de:4722
362c19:dd:d9:dd:c25:c25:94de:4723/1282c19:dd:d9:dd:c25:c25:94de:4723
372c19:dd:d9:dd:c25:c25:94de:4724/1282c19:dd:d9:dd:c25:c25:94de:4724
382c19:dd:d9:dd:c25:c25:94de:4725/1282c19:dd:d9:dd:c25:c25:94de:4725
392c19:dd:d9:dd:c25:c25:94de:4726/1282c19:dd:d9:dd:c25:c25:94de:4726
402c19:dd:d9:dd:c25:c25:94de:4727/1282c19:dd:d9:dd:c25:c25:94de:4727
412c19:dd:d9:dd:c25:c25:94de:4728/1282c19:dd:d9:dd:c25:c25:94de:4728
422c19:dd:d9:dd:c25:c25:94de:4729/1282c19:dd:d9:dd:c25:c25:94de:4729
432c19:dd:d9:dd:c25:c25:94de:472a/1282c19:dd:d9:dd:c25:c25:94de:472a
442c19:dd:d9:dd:c25:c25:94de:472b/1282c19:dd:d9:dd:c25:c25:94de:472b
452c19:dd:d9:dd:c25:c25:94de:472c/1282c19:dd:d9:dd:c25:c25:94de:472c
462c19:dd:d9:dd:c25:c25:94de:472d/1282c19:dd:d9:dd:c25:c25:94de:472d
472c19:dd:d9:dd:c25:c25:94de:472e/1282c19:dd:d9:dd:c25:c25:94de:472e
482c19:dd:d9:dd:c25:c25:94de:472f/1282c19:dd:d9:dd:c25:c25:94de:472f
492c19:dd:d9:dd:c25:c25:94de:4730/1282c19:dd:d9:dd:c25:c25:94de:4730
502c19:dd:d9:dd:c25:c25:94de:4731/1282c19:dd:d9:dd:c25:c25:94de:4731
512c19:dd:d9:dd:c25:c25:94de:4732/1282c19:dd:d9:dd:c25:c25:94de:4732
522c19:dd:d9:dd:c25:c25:94de:4733/1282c19:dd:d9:dd:c25:c25:94de:4733
532c19:dd:d9:dd:c25:c25:94de:4734/1282c19:dd:d9:dd:c25:c25:94de:4734
542c19:dd:d9:dd:c25:c25:94de:4735/1282c19:dd:d9:dd:c25:c25:94de:4735
552c19:dd:d9:dd:c25:c25:94de:4736/1282c19:dd:d9:dd:c25:c25:94de:4736
562c19:dd:d9:dd:c25:c25:94de:4737/1282c19:dd:d9:dd:c25:c25:94de:4737
572c19:dd:d9:dd:c25:c25:94de:4738/1282c19:dd:d9:dd:c25:c25:94de:4738
582c19:dd:d9:dd:c25:c25:94de:4739/1282c19:dd:d9:dd:c25:c25:94de:4739
592c19:dd:d9:dd:c25:c25:94de:473a/1282c19:dd:d9:dd:c25:c25:94de:473a
602c19:dd:d9:dd:c25:c25:94de:473b/1282c19:dd:d9:dd:c25:c25:94de:473b
612c19:dd:d9:dd:c25:c25:94de:473c/1282c19:dd:d9:dd:c25:c25:94de:473c
622c19:dd:d9:dd:c25:c25:94de:473d/1282c19:dd:d9:dd:c25:c25:94de:473d
632c19:dd:d9:dd:c25:c25:94de:473e/1282c19:dd:d9:dd:c25:c25:94de:473e
642c19:dd:d9:dd:c25:c25:94de:473f/1282c19:dd:d9:dd:c25:c25:94de:473f
652c19:dd:d9:dd:c25:c25:94de:4740/1282c19:dd:d9:dd:c25:c25:94de:4740
662c19:dd:d9:dd:c25:c25:94de:4741/1282c19:dd:d9:dd:c25:c25:94de:4741
672c19:dd:d9:dd:c25:c25:94de:4742/1282c19:dd:d9:dd:c25:c25:94de:4742
682c19:dd:d9:dd:c25:c25:94de:4743/1282c19:dd:d9:dd:c25:c25:94de:4743
692c19:dd:d9:dd:c25:c25:94de:4744/1282c19:dd:d9:dd:c25:c25:94de:4744
702c19:dd:d9:dd:c25:c25:94de:4745/1282c19:dd:d9:dd:c25:c25:94de:4745
712c19:dd:d9:dd:c25:c25:94de:4746/1282c19:dd:d9:dd:c25:c25:94de:4746
722c19:dd:d9:dd:c25:c25:94de:4747/1282c19:dd:d9:dd:c25:c25:94de:4747
732c19:dd:d9:dd:c25:c25:94de:4748/1282c19:dd:d9:dd:c25:c25:94de:4748
742c19:dd:d9:dd:c25:c25:94de:4749/1282c19:dd:d9:dd:c25:c25:94de:4749
752c19:dd:d9:dd:c25:c25:94de:474a/1282c19:dd:d9:dd:c25:c25:94de:474a
762c19:dd:d9:dd:c25:c25:94de:474b/1282c19:dd:d9:dd:c25:c25:94de:474b
772c19:dd:d9:dd:c25:c25:94de:474c/1282c19:dd:d9:dd:c25:c25:94de:474c
782c19:dd:d9:dd:c25:c25:94de:474d/1282c19:dd:d9:dd:c25:c25:94de:474d
792c19:dd:d9:dd:c25:c25:94de:474e/1282c19:dd:d9:dd:c25:c25:94de:474e
802c19:dd:d9:dd:c25:c25:94de:474f/1282c19:dd:d9:dd:c25:c25:94de:474f
812c19:dd:d9:dd:c25:c25:94de:4750/1282c19:dd:d9:dd:c25:c25:94de:4750
822c19:dd:d9:dd:c25:c25:94de:4751/1282c19:dd:d9:dd:c25:c25:94de:4751
832c19:dd:d9:dd:c25:c25:94de:4752/1282c19:dd:d9:dd:c25:c25:94de:4752
842c19:dd:d9:dd:c25:c25:94de:4753/1282c19:dd:d9:dd:c25:c25:94de:4753
852c19:dd:d9:dd:c25:c25:94de:4754/1282c19:dd:d9:dd:c25:c25:94de:4754
862c19:dd:d9:dd:c25:c25:94de:4755/1282c19:dd:d9:dd:c25:c25:94de:4755
872c19:dd:d9:dd:c25:c25:94de:4756/1282c19:dd:d9:dd:c25:c25:94de:4756
882c19:dd:d9:dd:c25:c25:94de:4757/1282c19:dd:d9:dd:c25:c25:94de:4757
892c19:dd:d9:dd:c25:c25:94de:4758/1282c19:dd:d9:dd:c25:c25:94de:4758
902c19:dd:d9:dd:c25:c25:94de:4759/1282c19:dd:d9:dd:c25:c25:94de:4759
912c19:dd:d9:dd:c25:c25:94de:475a/1282c19:dd:d9:dd:c25:c25:94de:475a
922c19:dd:d9:dd:c25:c25:94de:475b/1282c19:dd:d9:dd:c25:c25:94de:475b
932c19:dd:d9:dd:c25:c25:94de:475c/1282c19:dd:d9:dd:c25:c25:94de:475c
942c19:dd:d9:dd:c25:c25:94de:475d/1282c19:dd:d9:dd:c25:c25:94de:475d
952c19:dd:d9:dd:c25:c25:94de:475e/1282c19:dd:d9:dd:c25:c25:94de:475e
962c19:dd:d9:dd:c25:c25:94de:475f/1282c19:dd:d9:dd:c25:c25:94de:475f
972c19:dd:d9:dd:c25:c25:94de:4760/1282c19:dd:d9:dd:c25:c25:94de:4760
982c19:dd:d9:dd:c25:c25:94de:4761/1282c19:dd:d9:dd:c25:c25:94de:4761
992c19:dd:d9:dd:c25:c25:94de:4762/1282c19:dd:d9:dd:c25:c25:94de:4762
1002c19:dd:d9:dd:c25:c25:94de:4763/1282c19:dd:d9:dd:c25:c25:94de:4763
1012c19:dd:d9:dd:c25:c25:94de:4764/1282c19:dd:d9:dd:c25:c25:94de:4764
1022c19:dd:d9:dd:c25:c25:94de:4765/1282c19:dd:d9:dd:c25:c25:94de:4765
1032c19:dd:d9:dd:c25:c25:94de:4766/1282c19:dd:d9:dd:c25:c25:94de:4766
1042c19:dd:d9:dd:c25:c25:94de:4767/1282c19:dd:d9:dd:c25:c25:94de:4767
1052c19:dd:d9:dd:c25:c25:94de:4768/1282c19:dd:d9:dd:c25:c25:94de:4768
1062c19:dd:d9:dd:c25:c25:94de:4769/1282c19:dd:d9:dd:c25:c25:94de:4769
1072c19:dd:d9:dd:c25:c25:94de:476a/1282c19:dd:d9:dd:c25:c25:94de:476a
1082c19:dd:d9:dd:c25:c25:94de:476b/1282c19:dd:d9:dd:c25:c25:94de:476b
1092c19:dd:d9:dd:c25:c25:94de:476c/1282c19:dd:d9:dd:c25:c25:94de:476c
1102c19:dd:d9:dd:c25:c25:94de:476d/1282c19:dd:d9:dd:c25:c25:94de:476d
1112c19:dd:d9:dd:c25:c25:94de:476e/1282c19:dd:d9:dd:c25:c25:94de:476e
1122c19:dd:d9:dd:c25:c25:94de:476f/1282c19:dd:d9:dd:c25:c25:94de:476f
1132c19:dd:d9:dd:c25:c25:94de:4770/1282c19:dd:d9:dd:c25:c25:94de:4770
1142c19:dd:d9:dd:c25:c25:94de:4771/1282c19:dd:d9:dd:c25:c25:94de:4771
1152c19:dd:d9:dd:c25:c25:94de:4772/1282c19:dd:d9:dd:c25:c25:94de:4772
1162c19:dd:d9:dd:c25:c25:94de:4773/1282c19:dd:d9:dd:c25:c25:94de:4773
1172c19:dd:d9:dd:c25:c25:94de:4774/1282c19:dd:d9:dd:c25:c25:94de:4774
1182c19:dd:d9:dd:c25:c25:94de:4775/1282c19:dd:d9:dd:c25:c25:94de:4775
1192c19:dd:d9:dd:c25:c25:94de:4776/1282c19:dd:d9:dd:c25:c25:94de:4776
1202c19:dd:d9:dd:c25:c25:94de:4777/1282c19:dd:d9:dd:c25:c25:94de:4777
1212c19:dd:d9:dd:c25:c25:94de:4778/1282c19:dd:d9:dd:c25:c25:94de:4778
1222c19:dd:d9:dd:c25:c25:94de:4779/1282c19:dd:d9:dd:c25:c25:94de:4779
1232c19:dd:d9:dd:c25:c25:94de:477a/1282c19:dd:d9:dd:c25:c25:94de:477a
1242c19:dd:d9:dd:c25:c25:94de:477b/1282c19:dd:d9:dd:c25:c25:94de:477b
1252c19:dd:d9:dd:c25:c25:94de:477c/1282c19:dd:d9:dd:c25:c25:94de:477c
1262c19:dd:d9:dd:c25:c25:94de:477d/1282c19:dd:d9:dd:c25:c25:94de:477d
1272c19:dd:d9:dd:c25:c25:94de:477e/1282c19:dd:d9:dd:c25:c25:94de:477e
1282c19:dd:d9:dd:c25:c25:94de:477f/1282c19:dd:d9:dd:c25:c25:94de:477f
1292c19:dd:d9:dd:c25:c25:94de:4780/1282c19:dd:d9:dd:c25:c25:94de:4780
1302c19:dd:d9:dd:c25:c25:94de:4781/1282c19:dd:d9:dd:c25:c25:94de:4781
1312c19:dd:d9:dd:c25:c25:94de:4782/1282c19:dd:d9:dd:c25:c25:94de:4782
1322c19:dd:d9:dd:c25:c25:94de:4783/1282c19:dd:d9:dd:c25:c25:94de:4783
1332c19:dd:d9:dd:c25:c25:94de:4784/1282c19:dd:d9:dd:c25:c25:94de:4784
1342c19:dd:d9:dd:c25:c25:94de:4785/1282c19:dd:d9:dd:c25:c25:94de:4785
1352c19:dd:d9:dd:c25:c25:94de:4786/1282c19:dd:d9:dd:c25:c25:94de:4786
1362c19:dd:d9:dd:c25:c25:94de:4787/1282c19:dd:d9:dd:c25:c25:94de:4787
1372c19:dd:d9:dd:c25:c25:94de:4788/1282c19:dd:d9:dd:c25:c25:94de:4788
1382c19:dd:d9:dd:c25:c25:94de:4789/1282c19:dd:d9:dd:c25:c25:94de:4789
1392c19:dd:d9:dd:c25:c25:94de:478a/1282c19:dd:d9:dd:c25:c25:94de:478a
1402c19:dd:d9:dd:c25:c25:94de:478b/1282c19:dd:d9:dd:c25:c25:94de:478b
1412c19:dd:d9:dd:c25:c25:94de:478c/1282c19:dd:d9:dd:c25:c25:94de:478c
1422c19:dd:d9:dd:c25:c25:94de:478d/1282c19:dd:d9:dd:c25:c25:94de:478d
1432c19:dd:d9:dd:c25:c25:94de:478e/1282c19:dd:d9:dd:c25:c25:94de:478e
1442c19:dd:d9:dd:c25:c25:94de:478f/1282c19:dd:d9:dd:c25:c25:94de:478f
1452c19:dd:d9:dd:c25:c25:94de:4790/1282c19:dd:d9:dd:c25:c25:94de:4790
1462c19:dd:d9:dd:c25:c25:94de:4791/1282c19:dd:d9:dd:c25:c25:94de:4791
1472c19:dd:d9:dd:c25:c25:94de:4792/1282c19:dd:d9:dd:c25:c25:94de:4792
1482c19:dd:d9:dd:c25:c25:94de:4793/1282c19:dd:d9:dd:c25:c25:94de:4793
1492c19:dd:d9:dd:c25:c25:94de:4794/1282c19:dd:d9:dd:c25:c25:94de:4794
1502c19:dd:d9:dd:c25:c25:94de:4795/1282c19:dd:d9:dd:c25:c25:94de:4795
1512c19:dd:d9:dd:c25:c25:94de:4796/1282c19:dd:d9:dd:c25:c25:94de:4796
1522c19:dd:d9:dd:c25:c25:94de:4797/1282c19:dd:d9:dd:c25:c25:94de:4797
1532c19:dd:d9:dd:c25:c25:94de:4798/1282c19:dd:d9:dd:c25:c25:94de:4798
1542c19:dd:d9:dd:c25:c25:94de:4799/1282c19:dd:d9:dd:c25:c25:94de:4799
1552c19:dd:d9:dd:c25:c25:94de:479a/1282c19:dd:d9:dd:c25:c25:94de:479a
1562c19:dd:d9:dd:c25:c25:94de:479b/1282c19:dd:d9:dd:c25:c25:94de:479b
1572c19:dd:d9:dd:c25:c25:94de:479c/1282c19:dd:d9:dd:c25:c25:94de:479c
1582c19:dd:d9:dd:c25:c25:94de:479d/1282c19:dd:d9:dd:c25:c25:94de:479d
1592c19:dd:d9:dd:c25:c25:94de:479e/1282c19:dd:d9:dd:c25:c25:94de:479e
1602c19:dd:d9:dd:c25:c25:94de:479f/1282c19:dd:d9:dd:c25:c25:94de:479f
1612c19:dd:d9:dd:c25:c25:94de:47a0/1282c19:dd:d9:dd:c25:c25:94de:47a0
1622c19:dd:d9:dd:c25:c25:94de:47a1/1282c19:dd:d9:dd:c25:c25:94de:47a1
1632c19:dd:d9:dd:c25:c25:94de:47a2/1282c19:dd:d9:dd:c25:c25:94de:47a2
1642c19:dd:d9:dd:c25:c25:94de:47a3/1282c19:dd:d9:dd:c25:c25:94de:47a3
1652c19:dd:d9:dd:c25:c25:94de:47a4/1282c19:dd:d9:dd:c25:c25:94de:47a4
1662c19:dd:d9:dd:c25:c25:94de:47a5/1282c19:dd:d9:dd:c25:c25:94de:47a5
1672c19:dd:d9:dd:c25:c25:94de:47a6/1282c19:dd:d9:dd:c25:c25:94de:47a6
1682c19:dd:d9:dd:c25:c25:94de:47a7/1282c19:dd:d9:dd:c25:c25:94de:47a7
1692c19:dd:d9:dd:c25:c25:94de:47a8/1282c19:dd:d9:dd:c25:c25:94de:47a8
1702c19:dd:d9:dd:c25:c25:94de:47a9/1282c19:dd:d9:dd:c25:c25:94de:47a9
1712c19:dd:d9:dd:c25:c25:94de:47aa/1282c19:dd:d9:dd:c25:c25:94de:47aa
1722c19:dd:d9:dd:c25:c25:94de:47ab/1282c19:dd:d9:dd:c25:c25:94de:47ab
1732c19:dd:d9:dd:c25:c25:94de:47ac/1282c19:dd:d9:dd:c25:c25:94de:47ac
1742c19:dd:d9:dd:c25:c25:94de:47ad/1282c19:dd:d9:dd:c25:c25:94de:47ad
1752c19:dd:d9:dd:c25:c25:94de:47ae/1282c19:dd:d9:dd:c25:c25:94de:47ae
1762c19:dd:d9:dd:c25:c25:94de:47af/1282c19:dd:d9:dd:c25:c25:94de:47af
1772c19:dd:d9:dd:c25:c25:94de:47b0/1282c19:dd:d9:dd:c25:c25:94de:47b0
1782c19:dd:d9:dd:c25:c25:94de:47b1/1282c19:dd:d9:dd:c25:c25:94de:47b1
1792c19:dd:d9:dd:c25:c25:94de:47b2/1282c19:dd:d9:dd:c25:c25:94de:47b2
1802c19:dd:d9:dd:c25:c25:94de:47b3/1282c19:dd:d9:dd:c25:c25:94de:47b3
1812c19:dd:d9:dd:c25:c25:94de:47b4/1282c19:dd:d9:dd:c25:c25:94de:47b4
1822c19:dd:d9:dd:c25:c25:94de:47b5/1282c19:dd:d9:dd:c25:c25:94de:47b5
1832c19:dd:d9:dd:c25:c25:94de:47b6/1282c19:dd:d9:dd:c25:c25:94de:47b6
1842c19:dd:d9:dd:c25:c25:94de:47b7/1282c19:dd:d9:dd:c25:c25:94de:47b7
1852c19:dd:d9:dd:c25:c25:94de:47b8/1282c19:dd:d9:dd:c25:c25:94de:47b8
1862c19:dd:d9:dd:c25:c25:94de:47b9/1282c19:dd:d9:dd:c25:c25:94de:47b9
1872c19:dd:d9:dd:c25:c25:94de:47ba/1282c19:dd:d9:dd:c25:c25:94de:47ba
1882c19:dd:d9:dd:c25:c25:94de:47bb/1282c19:dd:d9:dd:c25:c25:94de:47bb
1892c19:dd:d9:dd:c25:c25:94de:47bc/1282c19:dd:d9:dd:c25:c25:94de:47bc
1902c19:dd:d9:dd:c25:c25:94de:47bd/1282c19:dd:d9:dd:c25:c25:94de:47bd
1912c19:dd:d9:dd:c25:c25:94de:47be/1282c19:dd:d9:dd:c25:c25:94de:47be
1922c19:dd:d9:dd:c25:c25:94de:47bf/1282c19:dd:d9:dd:c25:c25:94de:47bf
1932c19:dd:d9:dd:c25:c25:94de:47c0/1282c19:dd:d9:dd:c25:c25:94de:47c0
1942c19:dd:d9:dd:c25:c25:94de:47c1/1282c19:dd:d9:dd:c25:c25:94de:47c1
1952c19:dd:d9:dd:c25:c25:94de:47c2/1282c19:dd:d9:dd:c25:c25:94de:47c2
1962c19:dd:d9:dd:c25:c25:94de:47c3/1282c19:dd:d9:dd:c25:c25:94de:47c3
1972c19:dd:d9:dd:c25:c25:94de:47c4/1282c19:dd:d9:dd:c25:c25:94de:47c4
1982c19:dd:d9:dd:c25:c25:94de:47c5/1282c19:dd:d9:dd:c25:c25:94de:47c5
1992c19:dd:d9:dd:c25:c25:94de:47c6/1282c19:dd:d9:dd:c25:c25:94de:47c6
2002c19:dd:d9:dd:c25:c25:94de:47c7/1282c19:dd:d9:dd:c25:c25:94de:47c7
2012c19:dd:d9:dd:c25:c25:94de:47c8/1282c19:dd:d9:dd:c25:c25:94de:47c8
2022c19:dd:d9:dd:c25:c25:94de:47c9/1282c19:dd:d9:dd:c25:c25:94de:47c9
2032c19:dd:d9:dd:c25:c25:94de:47ca/1282c19:dd:d9:dd:c25:c25:94de:47ca
2042c19:dd:d9:dd:c25:c25:94de:47cb/1282c19:dd:d9:dd:c25:c25:94de:47cb
2052c19:dd:d9:dd:c25:c25:94de:47cc/1282c19:dd:d9:dd:c25:c25:94de:47cc
2062c19:dd:d9:dd:c25:c25:94de:47cd/1282c19:dd:d9:dd:c25:c25:94de:47cd
2072c19:dd:d9:dd:c25:c25:94de:47ce/1282c19:dd:d9:dd:c25:c25:94de:47ce
2082c19:dd:d9:dd:c25:c25:94de:47cf/1282c19:dd:d9:dd:c25:c25:94de:47cf
2092c19:dd:d9:dd:c25:c25:94de:47d0/1282c19:dd:d9:dd:c25:c25:94de:47d0
2102c19:dd:d9:dd:c25:c25:94de:47d1/1282c19:dd:d9:dd:c25:c25:94de:47d1
2112c19:dd:d9:dd:c25:c25:94de:47d2/1282c19:dd:d9:dd:c25:c25:94de:47d2
2122c19:dd:d9:dd:c25:c25:94de:47d3/1282c19:dd:d9:dd:c25:c25:94de:47d3
2132c19:dd:d9:dd:c25:c25:94de:47d4/1282c19:dd:d9:dd:c25:c25:94de:47d4
2142c19:dd:d9:dd:c25:c25:94de:47d5/1282c19:dd:d9:dd:c25:c25:94de:47d5
2152c19:dd:d9:dd:c25:c25:94de:47d6/1282c19:dd:d9:dd:c25:c25:94de:47d6
2162c19:dd:d9:dd:c25:c25:94de:47d7/1282c19:dd:d9:dd:c25:c25:94de:47d7
2172c19:dd:d9:dd:c25:c25:94de:47d8/1282c19:dd:d9:dd:c25:c25:94de:47d8
2182c19:dd:d9:dd:c25:c25:94de:47d9/1282c19:dd:d9:dd:c25:c25:94de:47d9
2192c19:dd:d9:dd:c25:c25:94de:47da/1282c19:dd:d9:dd:c25:c25:94de:47da
2202c19:dd:d9:dd:c25:c25:94de:47db/1282c19:dd:d9:dd:c25:c25:94de:47db
2212c19:dd:d9:dd:c25:c25:94de:47dc/1282c19:dd:d9:dd:c25:c25:94de:47dc
2222c19:dd:d9:dd:c25:c25:94de:47dd/1282c19:dd:d9:dd:c25:c25:94de:47dd
2232c19:dd:d9:dd:c25:c25:94de:47de/1282c19:dd:d9:dd:c25:c25:94de:47de
2242c19:dd:d9:dd:c25:c25:94de:47df/1282c19:dd:d9:dd:c25:c25:94de:47df
2252c19:dd:d9:dd:c25:c25:94de:47e0/1282c19:dd:d9:dd:c25:c25:94de:47e0
2262c19:dd:d9:dd:c25:c25:94de:47e1/1282c19:dd:d9:dd:c25:c25:94de:47e1
2272c19:dd:d9:dd:c25:c25:94de:47e2/1282c19:dd:d9:dd:c25:c25:94de:47e2
2282c19:dd:d9:dd:c25:c25:94de:47e3/1282c19:dd:d9:dd:c25:c25:94de:47e3
2292c19:dd:d9:dd:c25:c25:94de:47e4/1282c19:dd:d9:dd:c25:c25:94de:47e4
2302c19:dd:d9:dd:c25:c25:94de:47e5/1282c19:dd:d9:dd:c25:c25:94de:47e5
2312c19:dd:d9:dd:c25:c25:94de:47e6/1282c19:dd:d9:dd:c25:c25:94de:47e6
2322c19:dd:d9:dd:c25:c25:94de:47e7/1282c19:dd:d9:dd:c25:c25:94de:47e7
2332c19:dd:d9:dd:c25:c25:94de:47e8/1282c19:dd:d9:dd:c25:c25:94de:47e8
2342c19:dd:d9:dd:c25:c25:94de:47e9/1282c19:dd:d9:dd:c25:c25:94de:47e9
2352c19:dd:d9:dd:c25:c25:94de:47ea/1282c19:dd:d9:dd:c25:c25:94de:47ea
2362c19:dd:d9:dd:c25:c25:94de:47eb/1282c19:dd:d9:dd:c25:c25:94de:47eb
2372c19:dd:d9:dd:c25:c25:94de:47ec/1282c19:dd:d9:dd:c25:c25:94de:47ec
2382c19:dd:d9:dd:c25:c25:94de:47ed/1282c19:dd:d9:dd:c25:c25:94de:47ed
2392c19:dd:d9:dd:c25:c25:94de:47ee/1282c19:dd:d9:dd:c25:c25:94de:47ee
2402c19:dd:d9:dd:c25:c25:94de:47ef/1282c19:dd:d9:dd:c25:c25:94de:47ef
2412c19:dd:d9:dd:c25:c25:94de:47f0/1282c19:dd:d9:dd:c25:c25:94de:47f0
2422c19:dd:d9:dd:c25:c25:94de:47f1/1282c19:dd:d9:dd:c25:c25:94de:47f1
2432c19:dd:d9:dd:c25:c25:94de:47f2/1282c19:dd:d9:dd:c25:c25:94de:47f2
2442c19:dd:d9:dd:c25:c25:94de:47f3/1282c19:dd:d9:dd:c25:c25:94de:47f3
2452c19:dd:d9:dd:c25:c25:94de:47f4/1282c19:dd:d9:dd:c25:c25:94de:47f4
2462c19:dd:d9:dd:c25:c25:94de:47f5/1282c19:dd:d9:dd:c25:c25:94de:47f5
2472c19:dd:d9:dd:c25:c25:94de:47f6/1282c19:dd:d9:dd:c25:c25:94de:47f6
2482c19:dd:d9:dd:c25:c25:94de:47f7/1282c19:dd:d9:dd:c25:c25:94de:47f7
2492c19:dd:d9:dd:c25:c25:94de:47f8/1282c19:dd:d9:dd:c25:c25:94de:47f8
2502c19:dd:d9:dd:c25:c25:94de:47f9/1282c19:dd:d9:dd:c25:c25:94de:47f9
2512c19:dd:d9:dd:c25:c25:94de:47fa/1282c19:dd:d9:dd:c25:c25:94de:47fa
2522c19:dd:d9:dd:c25:c25:94de:47fb/1282c19:dd:d9:dd:c25:c25:94de:47fb
2532c19:dd:d9:dd:c25:c25:94de:47fc/1282c19:dd:d9:dd:c25:c25:94de:47fc
2542c19:dd:d9:dd:c25:c25:94de:47fd/1282c19:dd:d9:dd:c25:c25:94de:47fd
2552c19:dd:d9:dd:c25:c25:94de:47fe/1282c19:dd:d9:dd:c25:c25:94de:47fe
2562c19:dd:d9:dd:c25:c25:94de:47ff/1282c19:dd:d9:dd:c25:c25:94de:47ff

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.