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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.

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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.

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Remote supportLet a Surftec engineer connect to your computer to help you.All workingA full-screen confirmation that everything is up and running.

Surftec

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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/20
Addresses2^108
/64 networks2^44
Network
ff06:6000::/20
First address
ff06:6000::
Last address
ff06:6fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
ff06:6000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
6.6.0.f.f.ip6.arpa
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

ff06:6000::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1ff06:6000::/28ff06:600f:ffff:ffff:ffff:ffff:ffff:ffff
2ff06:6010::/28ff06:601f:ffff:ffff:ffff:ffff:ffff:ffff
3ff06:6020::/28ff06:602f:ffff:ffff:ffff:ffff:ffff:ffff
4ff06:6030::/28ff06:603f:ffff:ffff:ffff:ffff:ffff:ffff
5ff06:6040::/28ff06:604f:ffff:ffff:ffff:ffff:ffff:ffff
6ff06:6050::/28ff06:605f:ffff:ffff:ffff:ffff:ffff:ffff
7ff06:6060::/28ff06:606f:ffff:ffff:ffff:ffff:ffff:ffff
8ff06:6070::/28ff06:607f:ffff:ffff:ffff:ffff:ffff:ffff
9ff06:6080::/28ff06:608f:ffff:ffff:ffff:ffff:ffff:ffff
10ff06:6090::/28ff06:609f:ffff:ffff:ffff:ffff:ffff:ffff
11ff06:60a0::/28ff06:60af:ffff:ffff:ffff:ffff:ffff:ffff
12ff06:60b0::/28ff06:60bf:ffff:ffff:ffff:ffff:ffff:ffff
13ff06:60c0::/28ff06:60cf:ffff:ffff:ffff:ffff:ffff:ffff
14ff06:60d0::/28ff06:60df:ffff:ffff:ffff:ffff:ffff:ffff
15ff06:60e0::/28ff06:60ef:ffff:ffff:ffff:ffff:ffff:ffff
16ff06:60f0::/28ff06:60ff:ffff:ffff:ffff:ffff:ffff:ffff
17ff06:6100::/28ff06:610f:ffff:ffff:ffff:ffff:ffff:ffff
18ff06:6110::/28ff06:611f:ffff:ffff:ffff:ffff:ffff:ffff
19ff06:6120::/28ff06:612f:ffff:ffff:ffff:ffff:ffff:ffff
20ff06:6130::/28ff06:613f:ffff:ffff:ffff:ffff:ffff:ffff
21ff06:6140::/28ff06:614f:ffff:ffff:ffff:ffff:ffff:ffff
22ff06:6150::/28ff06:615f:ffff:ffff:ffff:ffff:ffff:ffff
23ff06:6160::/28ff06:616f:ffff:ffff:ffff:ffff:ffff:ffff
24ff06:6170::/28ff06:617f:ffff:ffff:ffff:ffff:ffff:ffff
25ff06:6180::/28ff06:618f:ffff:ffff:ffff:ffff:ffff:ffff
26ff06:6190::/28ff06:619f:ffff:ffff:ffff:ffff:ffff:ffff
27ff06:61a0::/28ff06:61af:ffff:ffff:ffff:ffff:ffff:ffff
28ff06:61b0::/28ff06:61bf:ffff:ffff:ffff:ffff:ffff:ffff
29ff06:61c0::/28ff06:61cf:ffff:ffff:ffff:ffff:ffff:ffff
30ff06:61d0::/28ff06:61df:ffff:ffff:ffff:ffff:ffff:ffff
31ff06:61e0::/28ff06:61ef:ffff:ffff:ffff:ffff:ffff:ffff
32ff06:61f0::/28ff06:61ff:ffff:ffff:ffff:ffff:ffff:ffff
33ff06:6200::/28ff06:620f:ffff:ffff:ffff:ffff:ffff:ffff
34ff06:6210::/28ff06:621f:ffff:ffff:ffff:ffff:ffff:ffff
35ff06:6220::/28ff06:622f:ffff:ffff:ffff:ffff:ffff:ffff
36ff06:6230::/28ff06:623f:ffff:ffff:ffff:ffff:ffff:ffff
37ff06:6240::/28ff06:624f:ffff:ffff:ffff:ffff:ffff:ffff
38ff06:6250::/28ff06:625f:ffff:ffff:ffff:ffff:ffff:ffff
39ff06:6260::/28ff06:626f:ffff:ffff:ffff:ffff:ffff:ffff
40ff06:6270::/28ff06:627f:ffff:ffff:ffff:ffff:ffff:ffff
41ff06:6280::/28ff06:628f:ffff:ffff:ffff:ffff:ffff:ffff
42ff06:6290::/28ff06:629f:ffff:ffff:ffff:ffff:ffff:ffff
43ff06:62a0::/28ff06:62af:ffff:ffff:ffff:ffff:ffff:ffff
44ff06:62b0::/28ff06:62bf:ffff:ffff:ffff:ffff:ffff:ffff
45ff06:62c0::/28ff06:62cf:ffff:ffff:ffff:ffff:ffff:ffff
46ff06:62d0::/28ff06:62df:ffff:ffff:ffff:ffff:ffff:ffff
47ff06:62e0::/28ff06:62ef:ffff:ffff:ffff:ffff:ffff:ffff
48ff06:62f0::/28ff06:62ff:ffff:ffff:ffff:ffff:ffff:ffff
49ff06:6300::/28ff06:630f:ffff:ffff:ffff:ffff:ffff:ffff
50ff06:6310::/28ff06:631f:ffff:ffff:ffff:ffff:ffff:ffff
51ff06:6320::/28ff06:632f:ffff:ffff:ffff:ffff:ffff:ffff
52ff06:6330::/28ff06:633f:ffff:ffff:ffff:ffff:ffff:ffff
53ff06:6340::/28ff06:634f:ffff:ffff:ffff:ffff:ffff:ffff
54ff06:6350::/28ff06:635f:ffff:ffff:ffff:ffff:ffff:ffff
55ff06:6360::/28ff06:636f:ffff:ffff:ffff:ffff:ffff:ffff
56ff06:6370::/28ff06:637f:ffff:ffff:ffff:ffff:ffff:ffff
57ff06:6380::/28ff06:638f:ffff:ffff:ffff:ffff:ffff:ffff
58ff06:6390::/28ff06:639f:ffff:ffff:ffff:ffff:ffff:ffff
59ff06:63a0::/28ff06:63af:ffff:ffff:ffff:ffff:ffff:ffff
60ff06:63b0::/28ff06:63bf:ffff:ffff:ffff:ffff:ffff:ffff
61ff06:63c0::/28ff06:63cf:ffff:ffff:ffff:ffff:ffff:ffff
62ff06:63d0::/28ff06:63df:ffff:ffff:ffff:ffff:ffff:ffff
63ff06:63e0::/28ff06:63ef:ffff:ffff:ffff:ffff:ffff:ffff
64ff06:63f0::/28ff06:63ff:ffff:ffff:ffff:ffff:ffff:ffff
65ff06:6400::/28ff06:640f:ffff:ffff:ffff:ffff:ffff:ffff
66ff06:6410::/28ff06:641f:ffff:ffff:ffff:ffff:ffff:ffff
67ff06:6420::/28ff06:642f:ffff:ffff:ffff:ffff:ffff:ffff
68ff06:6430::/28ff06:643f:ffff:ffff:ffff:ffff:ffff:ffff
69ff06:6440::/28ff06:644f:ffff:ffff:ffff:ffff:ffff:ffff
70ff06:6450::/28ff06:645f:ffff:ffff:ffff:ffff:ffff:ffff
71ff06:6460::/28ff06:646f:ffff:ffff:ffff:ffff:ffff:ffff
72ff06:6470::/28ff06:647f:ffff:ffff:ffff:ffff:ffff:ffff
73ff06:6480::/28ff06:648f:ffff:ffff:ffff:ffff:ffff:ffff
74ff06:6490::/28ff06:649f:ffff:ffff:ffff:ffff:ffff:ffff
75ff06:64a0::/28ff06:64af:ffff:ffff:ffff:ffff:ffff:ffff
76ff06:64b0::/28ff06:64bf:ffff:ffff:ffff:ffff:ffff:ffff
77ff06:64c0::/28ff06:64cf:ffff:ffff:ffff:ffff:ffff:ffff
78ff06:64d0::/28ff06:64df:ffff:ffff:ffff:ffff:ffff:ffff
79ff06:64e0::/28ff06:64ef:ffff:ffff:ffff:ffff:ffff:ffff
80ff06:64f0::/28ff06:64ff:ffff:ffff:ffff:ffff:ffff:ffff
81ff06:6500::/28ff06:650f:ffff:ffff:ffff:ffff:ffff:ffff
82ff06:6510::/28ff06:651f:ffff:ffff:ffff:ffff:ffff:ffff
83ff06:6520::/28ff06:652f:ffff:ffff:ffff:ffff:ffff:ffff
84ff06:6530::/28ff06:653f:ffff:ffff:ffff:ffff:ffff:ffff
85ff06:6540::/28ff06:654f:ffff:ffff:ffff:ffff:ffff:ffff
86ff06:6550::/28ff06:655f:ffff:ffff:ffff:ffff:ffff:ffff
87ff06:6560::/28ff06:656f:ffff:ffff:ffff:ffff:ffff:ffff
88ff06:6570::/28ff06:657f:ffff:ffff:ffff:ffff:ffff:ffff
89ff06:6580::/28ff06:658f:ffff:ffff:ffff:ffff:ffff:ffff
90ff06:6590::/28ff06:659f:ffff:ffff:ffff:ffff:ffff:ffff
91ff06:65a0::/28ff06:65af:ffff:ffff:ffff:ffff:ffff:ffff
92ff06:65b0::/28ff06:65bf:ffff:ffff:ffff:ffff:ffff:ffff
93ff06:65c0::/28ff06:65cf:ffff:ffff:ffff:ffff:ffff:ffff
94ff06:65d0::/28ff06:65df:ffff:ffff:ffff:ffff:ffff:ffff
95ff06:65e0::/28ff06:65ef:ffff:ffff:ffff:ffff:ffff:ffff
96ff06:65f0::/28ff06:65ff:ffff:ffff:ffff:ffff:ffff:ffff
97ff06:6600::/28ff06:660f:ffff:ffff:ffff:ffff:ffff:ffff
98ff06:6610::/28ff06:661f:ffff:ffff:ffff:ffff:ffff:ffff
99ff06:6620::/28ff06:662f:ffff:ffff:ffff:ffff:ffff:ffff
100ff06:6630::/28ff06:663f:ffff:ffff:ffff:ffff:ffff:ffff
101ff06:6640::/28ff06:664f:ffff:ffff:ffff:ffff:ffff:ffff
102ff06:6650::/28ff06:665f:ffff:ffff:ffff:ffff:ffff:ffff
103ff06:6660::/28ff06:666f:ffff:ffff:ffff:ffff:ffff:ffff
104ff06:6670::/28ff06:667f:ffff:ffff:ffff:ffff:ffff:ffff
105ff06:6680::/28ff06:668f:ffff:ffff:ffff:ffff:ffff:ffff
106ff06:6690::/28ff06:669f:ffff:ffff:ffff:ffff:ffff:ffff
107ff06:66a0::/28ff06:66af:ffff:ffff:ffff:ffff:ffff:ffff
108ff06:66b0::/28ff06:66bf:ffff:ffff:ffff:ffff:ffff:ffff
109ff06:66c0::/28ff06:66cf:ffff:ffff:ffff:ffff:ffff:ffff
110ff06:66d0::/28ff06:66df:ffff:ffff:ffff:ffff:ffff:ffff
111ff06:66e0::/28ff06:66ef:ffff:ffff:ffff:ffff:ffff:ffff
112ff06:66f0::/28ff06:66ff:ffff:ffff:ffff:ffff:ffff:ffff
113ff06:6700::/28ff06:670f:ffff:ffff:ffff:ffff:ffff:ffff
114ff06:6710::/28ff06:671f:ffff:ffff:ffff:ffff:ffff:ffff
115ff06:6720::/28ff06:672f:ffff:ffff:ffff:ffff:ffff:ffff
116ff06:6730::/28ff06:673f:ffff:ffff:ffff:ffff:ffff:ffff
117ff06:6740::/28ff06:674f:ffff:ffff:ffff:ffff:ffff:ffff
118ff06:6750::/28ff06:675f:ffff:ffff:ffff:ffff:ffff:ffff
119ff06:6760::/28ff06:676f:ffff:ffff:ffff:ffff:ffff:ffff
120ff06:6770::/28ff06:677f:ffff:ffff:ffff:ffff:ffff:ffff
121ff06:6780::/28ff06:678f:ffff:ffff:ffff:ffff:ffff:ffff
122ff06:6790::/28ff06:679f:ffff:ffff:ffff:ffff:ffff:ffff
123ff06:67a0::/28ff06:67af:ffff:ffff:ffff:ffff:ffff:ffff
124ff06:67b0::/28ff06:67bf:ffff:ffff:ffff:ffff:ffff:ffff
125ff06:67c0::/28ff06:67cf:ffff:ffff:ffff:ffff:ffff:ffff
126ff06:67d0::/28ff06:67df:ffff:ffff:ffff:ffff:ffff:ffff
127ff06:67e0::/28ff06:67ef:ffff:ffff:ffff:ffff:ffff:ffff
128ff06:67f0::/28ff06:67ff:ffff:ffff:ffff:ffff:ffff:ffff
129ff06:6800::/28ff06:680f:ffff:ffff:ffff:ffff:ffff:ffff
130ff06:6810::/28ff06:681f:ffff:ffff:ffff:ffff:ffff:ffff
131ff06:6820::/28ff06:682f:ffff:ffff:ffff:ffff:ffff:ffff
132ff06:6830::/28ff06:683f:ffff:ffff:ffff:ffff:ffff:ffff
133ff06:6840::/28ff06:684f:ffff:ffff:ffff:ffff:ffff:ffff
134ff06:6850::/28ff06:685f:ffff:ffff:ffff:ffff:ffff:ffff
135ff06:6860::/28ff06:686f:ffff:ffff:ffff:ffff:ffff:ffff
136ff06:6870::/28ff06:687f:ffff:ffff:ffff:ffff:ffff:ffff
137ff06:6880::/28ff06:688f:ffff:ffff:ffff:ffff:ffff:ffff
138ff06:6890::/28ff06:689f:ffff:ffff:ffff:ffff:ffff:ffff
139ff06:68a0::/28ff06:68af:ffff:ffff:ffff:ffff:ffff:ffff
140ff06:68b0::/28ff06:68bf:ffff:ffff:ffff:ffff:ffff:ffff
141ff06:68c0::/28ff06:68cf:ffff:ffff:ffff:ffff:ffff:ffff
142ff06:68d0::/28ff06:68df:ffff:ffff:ffff:ffff:ffff:ffff
143ff06:68e0::/28ff06:68ef:ffff:ffff:ffff:ffff:ffff:ffff
144ff06:68f0::/28ff06:68ff:ffff:ffff:ffff:ffff:ffff:ffff
145ff06:6900::/28ff06:690f:ffff:ffff:ffff:ffff:ffff:ffff
146ff06:6910::/28ff06:691f:ffff:ffff:ffff:ffff:ffff:ffff
147ff06:6920::/28ff06:692f:ffff:ffff:ffff:ffff:ffff:ffff
148ff06:6930::/28ff06:693f:ffff:ffff:ffff:ffff:ffff:ffff
149ff06:6940::/28ff06:694f:ffff:ffff:ffff:ffff:ffff:ffff
150ff06:6950::/28ff06:695f:ffff:ffff:ffff:ffff:ffff:ffff
151ff06:6960::/28ff06:696f:ffff:ffff:ffff:ffff:ffff:ffff
152ff06:6970::/28ff06:697f:ffff:ffff:ffff:ffff:ffff:ffff
153ff06:6980::/28ff06:698f:ffff:ffff:ffff:ffff:ffff:ffff
154ff06:6990::/28ff06:699f:ffff:ffff:ffff:ffff:ffff:ffff
155ff06:69a0::/28ff06:69af:ffff:ffff:ffff:ffff:ffff:ffff
156ff06:69b0::/28ff06:69bf:ffff:ffff:ffff:ffff:ffff:ffff
157ff06:69c0::/28ff06:69cf:ffff:ffff:ffff:ffff:ffff:ffff
158ff06:69d0::/28ff06:69df:ffff:ffff:ffff:ffff:ffff:ffff
159ff06:69e0::/28ff06:69ef:ffff:ffff:ffff:ffff:ffff:ffff
160ff06:69f0::/28ff06:69ff:ffff:ffff:ffff:ffff:ffff:ffff
161ff06:6a00::/28ff06:6a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ff06:6a10::/28ff06:6a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ff06:6a20::/28ff06:6a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ff06:6a30::/28ff06:6a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ff06:6a40::/28ff06:6a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ff06:6a50::/28ff06:6a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ff06:6a60::/28ff06:6a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ff06:6a70::/28ff06:6a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ff06:6a80::/28ff06:6a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ff06:6a90::/28ff06:6a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ff06:6aa0::/28ff06:6aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ff06:6ab0::/28ff06:6abf:ffff:ffff:ffff:ffff:ffff:ffff
173ff06:6ac0::/28ff06:6acf:ffff:ffff:ffff:ffff:ffff:ffff
174ff06:6ad0::/28ff06:6adf:ffff:ffff:ffff:ffff:ffff:ffff
175ff06:6ae0::/28ff06:6aef:ffff:ffff:ffff:ffff:ffff:ffff
176ff06:6af0::/28ff06:6aff:ffff:ffff:ffff:ffff:ffff:ffff
177ff06:6b00::/28ff06:6b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ff06:6b10::/28ff06:6b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ff06:6b20::/28ff06:6b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ff06:6b30::/28ff06:6b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ff06:6b40::/28ff06:6b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ff06:6b50::/28ff06:6b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ff06:6b60::/28ff06:6b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ff06:6b70::/28ff06:6b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ff06:6b80::/28ff06:6b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ff06:6b90::/28ff06:6b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ff06:6ba0::/28ff06:6baf:ffff:ffff:ffff:ffff:ffff:ffff
188ff06:6bb0::/28ff06:6bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ff06:6bc0::/28ff06:6bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ff06:6bd0::/28ff06:6bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ff06:6be0::/28ff06:6bef:ffff:ffff:ffff:ffff:ffff:ffff
192ff06:6bf0::/28ff06:6bff:ffff:ffff:ffff:ffff:ffff:ffff
193ff06:6c00::/28ff06:6c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ff06:6c10::/28ff06:6c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ff06:6c20::/28ff06:6c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ff06:6c30::/28ff06:6c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ff06:6c40::/28ff06:6c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ff06:6c50::/28ff06:6c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ff06:6c60::/28ff06:6c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ff06:6c70::/28ff06:6c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ff06:6c80::/28ff06:6c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ff06:6c90::/28ff06:6c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ff06:6ca0::/28ff06:6caf:ffff:ffff:ffff:ffff:ffff:ffff
204ff06:6cb0::/28ff06:6cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ff06:6cc0::/28ff06:6ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ff06:6cd0::/28ff06:6cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ff06:6ce0::/28ff06:6cef:ffff:ffff:ffff:ffff:ffff:ffff
208ff06:6cf0::/28ff06:6cff:ffff:ffff:ffff:ffff:ffff:ffff
209ff06:6d00::/28ff06:6d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ff06:6d10::/28ff06:6d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ff06:6d20::/28ff06:6d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ff06:6d30::/28ff06:6d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ff06:6d40::/28ff06:6d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ff06:6d50::/28ff06:6d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ff06:6d60::/28ff06:6d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ff06:6d70::/28ff06:6d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ff06:6d80::/28ff06:6d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ff06:6d90::/28ff06:6d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ff06:6da0::/28ff06:6daf:ffff:ffff:ffff:ffff:ffff:ffff
220ff06:6db0::/28ff06:6dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ff06:6dc0::/28ff06:6dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ff06:6dd0::/28ff06:6ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ff06:6de0::/28ff06:6def:ffff:ffff:ffff:ffff:ffff:ffff
224ff06:6df0::/28ff06:6dff:ffff:ffff:ffff:ffff:ffff:ffff
225ff06:6e00::/28ff06:6e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ff06:6e10::/28ff06:6e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ff06:6e20::/28ff06:6e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ff06:6e30::/28ff06:6e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ff06:6e40::/28ff06:6e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ff06:6e50::/28ff06:6e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ff06:6e60::/28ff06:6e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ff06:6e70::/28ff06:6e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ff06:6e80::/28ff06:6e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ff06:6e90::/28ff06:6e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ff06:6ea0::/28ff06:6eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ff06:6eb0::/28ff06:6ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ff06:6ec0::/28ff06:6ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ff06:6ed0::/28ff06:6edf:ffff:ffff:ffff:ffff:ffff:ffff
239ff06:6ee0::/28ff06:6eef:ffff:ffff:ffff:ffff:ffff:ffff
240ff06:6ef0::/28ff06:6eff:ffff:ffff:ffff:ffff:ffff:ffff
241ff06:6f00::/28ff06:6f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ff06:6f10::/28ff06:6f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ff06:6f20::/28ff06:6f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ff06:6f30::/28ff06:6f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ff06:6f40::/28ff06:6f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ff06:6f50::/28ff06:6f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ff06:6f60::/28ff06:6f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ff06:6f70::/28ff06:6f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ff06:6f80::/28ff06:6f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ff06:6f90::/28ff06:6f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ff06:6fa0::/28ff06:6faf:ffff:ffff:ffff:ffff:ffff:ffff
252ff06:6fb0::/28ff06:6fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ff06:6fc0::/28ff06:6fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ff06:6fd0::/28ff06:6fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ff06:6fe0::/28ff06:6fef:ffff:ffff:ffff:ffff:ffff:ffff
256ff06:6ff0::/28ff06:6fff:ffff:ffff:ffff:ffff:ffff:ffff

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.