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/35
Addresses2^93
/64 networks536,870,912
Network
ffd2::/35
First address
ffd2::
Last address
ffd2:0:1fff:ffff:ffff:ffff:ffff:ffff
Addresses
9,903,520,314,283,042,199,192,993,792 (2^93)
/64 networks (LANs)
536,870,912
Full form
ffd2:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zones
0.0.0.0.0.2.d.f.f.ip6.arpa
1.0.0.0.0.2.d.f.f.ip6.arpa
/35 is not on a 4-bit boundary, so it takes 2 /36 zones.
Split into smaller subnets/48
/36 (2)/37 (4)/38 (8)/39 (16)/40 (32)/44 (512)/48 (8,192)

ffd2::/35 makes 8,192 subnets of /48; the first 256 are listed.

Subnets
#SubnetLast address
1ffd2::/48ffd2::ffff:ffff:ffff:ffff:ffff
2ffd2:0:1::/48ffd2:0:1:ffff:ffff:ffff:ffff:ffff
3ffd2:0:2::/48ffd2:0:2:ffff:ffff:ffff:ffff:ffff
4ffd2:0:3::/48ffd2:0:3:ffff:ffff:ffff:ffff:ffff
5ffd2:0:4::/48ffd2:0:4:ffff:ffff:ffff:ffff:ffff
6ffd2:0:5::/48ffd2:0:5:ffff:ffff:ffff:ffff:ffff
7ffd2:0:6::/48ffd2:0:6:ffff:ffff:ffff:ffff:ffff
8ffd2:0:7::/48ffd2:0:7:ffff:ffff:ffff:ffff:ffff
9ffd2:0:8::/48ffd2:0:8:ffff:ffff:ffff:ffff:ffff
10ffd2:0:9::/48ffd2:0:9:ffff:ffff:ffff:ffff:ffff
11ffd2:0:a::/48ffd2:0:a:ffff:ffff:ffff:ffff:ffff
12ffd2:0:b::/48ffd2:0:b:ffff:ffff:ffff:ffff:ffff
13ffd2:0:c::/48ffd2:0:c:ffff:ffff:ffff:ffff:ffff
14ffd2:0:d::/48ffd2:0:d:ffff:ffff:ffff:ffff:ffff
15ffd2:0:e::/48ffd2:0:e:ffff:ffff:ffff:ffff:ffff
16ffd2:0:f::/48ffd2:0:f:ffff:ffff:ffff:ffff:ffff
17ffd2:0:10::/48ffd2:0:10:ffff:ffff:ffff:ffff:ffff
18ffd2:0:11::/48ffd2:0:11:ffff:ffff:ffff:ffff:ffff
19ffd2:0:12::/48ffd2:0:12:ffff:ffff:ffff:ffff:ffff
20ffd2:0:13::/48ffd2:0:13:ffff:ffff:ffff:ffff:ffff
21ffd2:0:14::/48ffd2:0:14:ffff:ffff:ffff:ffff:ffff
22ffd2:0:15::/48ffd2:0:15:ffff:ffff:ffff:ffff:ffff
23ffd2:0:16::/48ffd2:0:16:ffff:ffff:ffff:ffff:ffff
24ffd2:0:17::/48ffd2:0:17:ffff:ffff:ffff:ffff:ffff
25ffd2:0:18::/48ffd2:0:18:ffff:ffff:ffff:ffff:ffff
26ffd2:0:19::/48ffd2:0:19:ffff:ffff:ffff:ffff:ffff
27ffd2:0:1a::/48ffd2:0:1a:ffff:ffff:ffff:ffff:ffff
28ffd2:0:1b::/48ffd2:0:1b:ffff:ffff:ffff:ffff:ffff
29ffd2:0:1c::/48ffd2:0:1c:ffff:ffff:ffff:ffff:ffff
30ffd2:0:1d::/48ffd2:0:1d:ffff:ffff:ffff:ffff:ffff
31ffd2:0:1e::/48ffd2:0:1e:ffff:ffff:ffff:ffff:ffff
32ffd2:0:1f::/48ffd2:0:1f:ffff:ffff:ffff:ffff:ffff
33ffd2:0:20::/48ffd2:0:20:ffff:ffff:ffff:ffff:ffff
34ffd2:0:21::/48ffd2:0:21:ffff:ffff:ffff:ffff:ffff
35ffd2:0:22::/48ffd2:0:22:ffff:ffff:ffff:ffff:ffff
36ffd2:0:23::/48ffd2:0:23:ffff:ffff:ffff:ffff:ffff
37ffd2:0:24::/48ffd2:0:24:ffff:ffff:ffff:ffff:ffff
38ffd2:0:25::/48ffd2:0:25:ffff:ffff:ffff:ffff:ffff
39ffd2:0:26::/48ffd2:0:26:ffff:ffff:ffff:ffff:ffff
40ffd2:0:27::/48ffd2:0:27:ffff:ffff:ffff:ffff:ffff
41ffd2:0:28::/48ffd2:0:28:ffff:ffff:ffff:ffff:ffff
42ffd2:0:29::/48ffd2:0:29:ffff:ffff:ffff:ffff:ffff
43ffd2:0:2a::/48ffd2:0:2a:ffff:ffff:ffff:ffff:ffff
44ffd2:0:2b::/48ffd2:0:2b:ffff:ffff:ffff:ffff:ffff
45ffd2:0:2c::/48ffd2:0:2c:ffff:ffff:ffff:ffff:ffff
46ffd2:0:2d::/48ffd2:0:2d:ffff:ffff:ffff:ffff:ffff
47ffd2:0:2e::/48ffd2:0:2e:ffff:ffff:ffff:ffff:ffff
48ffd2:0:2f::/48ffd2:0:2f:ffff:ffff:ffff:ffff:ffff
49ffd2:0:30::/48ffd2:0:30:ffff:ffff:ffff:ffff:ffff
50ffd2:0:31::/48ffd2:0:31:ffff:ffff:ffff:ffff:ffff
51ffd2:0:32::/48ffd2:0:32:ffff:ffff:ffff:ffff:ffff
52ffd2:0:33::/48ffd2:0:33:ffff:ffff:ffff:ffff:ffff
53ffd2:0:34::/48ffd2:0:34:ffff:ffff:ffff:ffff:ffff
54ffd2:0:35::/48ffd2:0:35:ffff:ffff:ffff:ffff:ffff
55ffd2:0:36::/48ffd2:0:36:ffff:ffff:ffff:ffff:ffff
56ffd2:0:37::/48ffd2:0:37:ffff:ffff:ffff:ffff:ffff
57ffd2:0:38::/48ffd2:0:38:ffff:ffff:ffff:ffff:ffff
58ffd2:0:39::/48ffd2:0:39:ffff:ffff:ffff:ffff:ffff
59ffd2:0:3a::/48ffd2:0:3a:ffff:ffff:ffff:ffff:ffff
60ffd2:0:3b::/48ffd2:0:3b:ffff:ffff:ffff:ffff:ffff
61ffd2:0:3c::/48ffd2:0:3c:ffff:ffff:ffff:ffff:ffff
62ffd2:0:3d::/48ffd2:0:3d:ffff:ffff:ffff:ffff:ffff
63ffd2:0:3e::/48ffd2:0:3e:ffff:ffff:ffff:ffff:ffff
64ffd2:0:3f::/48ffd2:0:3f:ffff:ffff:ffff:ffff:ffff
65ffd2:0:40::/48ffd2:0:40:ffff:ffff:ffff:ffff:ffff
66ffd2:0:41::/48ffd2:0:41:ffff:ffff:ffff:ffff:ffff
67ffd2:0:42::/48ffd2:0:42:ffff:ffff:ffff:ffff:ffff
68ffd2:0:43::/48ffd2:0:43:ffff:ffff:ffff:ffff:ffff
69ffd2:0:44::/48ffd2:0:44:ffff:ffff:ffff:ffff:ffff
70ffd2:0:45::/48ffd2:0:45:ffff:ffff:ffff:ffff:ffff
71ffd2:0:46::/48ffd2:0:46:ffff:ffff:ffff:ffff:ffff
72ffd2:0:47::/48ffd2:0:47:ffff:ffff:ffff:ffff:ffff
73ffd2:0:48::/48ffd2:0:48:ffff:ffff:ffff:ffff:ffff
74ffd2:0:49::/48ffd2:0:49:ffff:ffff:ffff:ffff:ffff
75ffd2:0:4a::/48ffd2:0:4a:ffff:ffff:ffff:ffff:ffff
76ffd2:0:4b::/48ffd2:0:4b:ffff:ffff:ffff:ffff:ffff
77ffd2:0:4c::/48ffd2:0:4c:ffff:ffff:ffff:ffff:ffff
78ffd2:0:4d::/48ffd2:0:4d:ffff:ffff:ffff:ffff:ffff
79ffd2:0:4e::/48ffd2:0:4e:ffff:ffff:ffff:ffff:ffff
80ffd2:0:4f::/48ffd2:0:4f:ffff:ffff:ffff:ffff:ffff
81ffd2:0:50::/48ffd2:0:50:ffff:ffff:ffff:ffff:ffff
82ffd2:0:51::/48ffd2:0:51:ffff:ffff:ffff:ffff:ffff
83ffd2:0:52::/48ffd2:0:52:ffff:ffff:ffff:ffff:ffff
84ffd2:0:53::/48ffd2:0:53:ffff:ffff:ffff:ffff:ffff
85ffd2:0:54::/48ffd2:0:54:ffff:ffff:ffff:ffff:ffff
86ffd2:0:55::/48ffd2:0:55:ffff:ffff:ffff:ffff:ffff
87ffd2:0:56::/48ffd2:0:56:ffff:ffff:ffff:ffff:ffff
88ffd2:0:57::/48ffd2:0:57:ffff:ffff:ffff:ffff:ffff
89ffd2:0:58::/48ffd2:0:58:ffff:ffff:ffff:ffff:ffff
90ffd2:0:59::/48ffd2:0:59:ffff:ffff:ffff:ffff:ffff
91ffd2:0:5a::/48ffd2:0:5a:ffff:ffff:ffff:ffff:ffff
92ffd2:0:5b::/48ffd2:0:5b:ffff:ffff:ffff:ffff:ffff
93ffd2:0:5c::/48ffd2:0:5c:ffff:ffff:ffff:ffff:ffff
94ffd2:0:5d::/48ffd2:0:5d:ffff:ffff:ffff:ffff:ffff
95ffd2:0:5e::/48ffd2:0:5e:ffff:ffff:ffff:ffff:ffff
96ffd2:0:5f::/48ffd2:0:5f:ffff:ffff:ffff:ffff:ffff
97ffd2:0:60::/48ffd2:0:60:ffff:ffff:ffff:ffff:ffff
98ffd2:0:61::/48ffd2:0:61:ffff:ffff:ffff:ffff:ffff
99ffd2:0:62::/48ffd2:0:62:ffff:ffff:ffff:ffff:ffff
100ffd2:0:63::/48ffd2:0:63:ffff:ffff:ffff:ffff:ffff
101ffd2:0:64::/48ffd2:0:64:ffff:ffff:ffff:ffff:ffff
102ffd2:0:65::/48ffd2:0:65:ffff:ffff:ffff:ffff:ffff
103ffd2:0:66::/48ffd2:0:66:ffff:ffff:ffff:ffff:ffff
104ffd2:0:67::/48ffd2:0:67:ffff:ffff:ffff:ffff:ffff
105ffd2:0:68::/48ffd2:0:68:ffff:ffff:ffff:ffff:ffff
106ffd2:0:69::/48ffd2:0:69:ffff:ffff:ffff:ffff:ffff
107ffd2:0:6a::/48ffd2:0:6a:ffff:ffff:ffff:ffff:ffff
108ffd2:0:6b::/48ffd2:0:6b:ffff:ffff:ffff:ffff:ffff
109ffd2:0:6c::/48ffd2:0:6c:ffff:ffff:ffff:ffff:ffff
110ffd2:0:6d::/48ffd2:0:6d:ffff:ffff:ffff:ffff:ffff
111ffd2:0:6e::/48ffd2:0:6e:ffff:ffff:ffff:ffff:ffff
112ffd2:0:6f::/48ffd2:0:6f:ffff:ffff:ffff:ffff:ffff
113ffd2:0:70::/48ffd2:0:70:ffff:ffff:ffff:ffff:ffff
114ffd2:0:71::/48ffd2:0:71:ffff:ffff:ffff:ffff:ffff
115ffd2:0:72::/48ffd2:0:72:ffff:ffff:ffff:ffff:ffff
116ffd2:0:73::/48ffd2:0:73:ffff:ffff:ffff:ffff:ffff
117ffd2:0:74::/48ffd2:0:74:ffff:ffff:ffff:ffff:ffff
118ffd2:0:75::/48ffd2:0:75:ffff:ffff:ffff:ffff:ffff
119ffd2:0:76::/48ffd2:0:76:ffff:ffff:ffff:ffff:ffff
120ffd2:0:77::/48ffd2:0:77:ffff:ffff:ffff:ffff:ffff
121ffd2:0:78::/48ffd2:0:78:ffff:ffff:ffff:ffff:ffff
122ffd2:0:79::/48ffd2:0:79:ffff:ffff:ffff:ffff:ffff
123ffd2:0:7a::/48ffd2:0:7a:ffff:ffff:ffff:ffff:ffff
124ffd2:0:7b::/48ffd2:0:7b:ffff:ffff:ffff:ffff:ffff
125ffd2:0:7c::/48ffd2:0:7c:ffff:ffff:ffff:ffff:ffff
126ffd2:0:7d::/48ffd2:0:7d:ffff:ffff:ffff:ffff:ffff
127ffd2:0:7e::/48ffd2:0:7e:ffff:ffff:ffff:ffff:ffff
128ffd2:0:7f::/48ffd2:0:7f:ffff:ffff:ffff:ffff:ffff
129ffd2:0:80::/48ffd2:0:80:ffff:ffff:ffff:ffff:ffff
130ffd2:0:81::/48ffd2:0:81:ffff:ffff:ffff:ffff:ffff
131ffd2:0:82::/48ffd2:0:82:ffff:ffff:ffff:ffff:ffff
132ffd2:0:83::/48ffd2:0:83:ffff:ffff:ffff:ffff:ffff
133ffd2:0:84::/48ffd2:0:84:ffff:ffff:ffff:ffff:ffff
134ffd2:0:85::/48ffd2:0:85:ffff:ffff:ffff:ffff:ffff
135ffd2:0:86::/48ffd2:0:86:ffff:ffff:ffff:ffff:ffff
136ffd2:0:87::/48ffd2:0:87:ffff:ffff:ffff:ffff:ffff
137ffd2:0:88::/48ffd2:0:88:ffff:ffff:ffff:ffff:ffff
138ffd2:0:89::/48ffd2:0:89:ffff:ffff:ffff:ffff:ffff
139ffd2:0:8a::/48ffd2:0:8a:ffff:ffff:ffff:ffff:ffff
140ffd2:0:8b::/48ffd2:0:8b:ffff:ffff:ffff:ffff:ffff
141ffd2:0:8c::/48ffd2:0:8c:ffff:ffff:ffff:ffff:ffff
142ffd2:0:8d::/48ffd2:0:8d:ffff:ffff:ffff:ffff:ffff
143ffd2:0:8e::/48ffd2:0:8e:ffff:ffff:ffff:ffff:ffff
144ffd2:0:8f::/48ffd2:0:8f:ffff:ffff:ffff:ffff:ffff
145ffd2:0:90::/48ffd2:0:90:ffff:ffff:ffff:ffff:ffff
146ffd2:0:91::/48ffd2:0:91:ffff:ffff:ffff:ffff:ffff
147ffd2:0:92::/48ffd2:0:92:ffff:ffff:ffff:ffff:ffff
148ffd2:0:93::/48ffd2:0:93:ffff:ffff:ffff:ffff:ffff
149ffd2:0:94::/48ffd2:0:94:ffff:ffff:ffff:ffff:ffff
150ffd2:0:95::/48ffd2:0:95:ffff:ffff:ffff:ffff:ffff
151ffd2:0:96::/48ffd2:0:96:ffff:ffff:ffff:ffff:ffff
152ffd2:0:97::/48ffd2:0:97:ffff:ffff:ffff:ffff:ffff
153ffd2:0:98::/48ffd2:0:98:ffff:ffff:ffff:ffff:ffff
154ffd2:0:99::/48ffd2:0:99:ffff:ffff:ffff:ffff:ffff
155ffd2:0:9a::/48ffd2:0:9a:ffff:ffff:ffff:ffff:ffff
156ffd2:0:9b::/48ffd2:0:9b:ffff:ffff:ffff:ffff:ffff
157ffd2:0:9c::/48ffd2:0:9c:ffff:ffff:ffff:ffff:ffff
158ffd2:0:9d::/48ffd2:0:9d:ffff:ffff:ffff:ffff:ffff
159ffd2:0:9e::/48ffd2:0:9e:ffff:ffff:ffff:ffff:ffff
160ffd2:0:9f::/48ffd2:0:9f:ffff:ffff:ffff:ffff:ffff
161ffd2:0:a0::/48ffd2:0:a0:ffff:ffff:ffff:ffff:ffff
162ffd2:0:a1::/48ffd2:0:a1:ffff:ffff:ffff:ffff:ffff
163ffd2:0:a2::/48ffd2:0:a2:ffff:ffff:ffff:ffff:ffff
164ffd2:0:a3::/48ffd2:0:a3:ffff:ffff:ffff:ffff:ffff
165ffd2:0:a4::/48ffd2:0:a4:ffff:ffff:ffff:ffff:ffff
166ffd2:0:a5::/48ffd2:0:a5:ffff:ffff:ffff:ffff:ffff
167ffd2:0:a6::/48ffd2:0:a6:ffff:ffff:ffff:ffff:ffff
168ffd2:0:a7::/48ffd2:0:a7:ffff:ffff:ffff:ffff:ffff
169ffd2:0:a8::/48ffd2:0:a8:ffff:ffff:ffff:ffff:ffff
170ffd2:0:a9::/48ffd2:0:a9:ffff:ffff:ffff:ffff:ffff
171ffd2:0:aa::/48ffd2:0:aa:ffff:ffff:ffff:ffff:ffff
172ffd2:0:ab::/48ffd2:0:ab:ffff:ffff:ffff:ffff:ffff
173ffd2:0:ac::/48ffd2:0:ac:ffff:ffff:ffff:ffff:ffff
174ffd2:0:ad::/48ffd2:0:ad:ffff:ffff:ffff:ffff:ffff
175ffd2:0:ae::/48ffd2:0:ae:ffff:ffff:ffff:ffff:ffff
176ffd2:0:af::/48ffd2:0:af:ffff:ffff:ffff:ffff:ffff
177ffd2:0:b0::/48ffd2:0:b0:ffff:ffff:ffff:ffff:ffff
178ffd2:0:b1::/48ffd2:0:b1:ffff:ffff:ffff:ffff:ffff
179ffd2:0:b2::/48ffd2:0:b2:ffff:ffff:ffff:ffff:ffff
180ffd2:0:b3::/48ffd2:0:b3:ffff:ffff:ffff:ffff:ffff
181ffd2:0:b4::/48ffd2:0:b4:ffff:ffff:ffff:ffff:ffff
182ffd2:0:b5::/48ffd2:0:b5:ffff:ffff:ffff:ffff:ffff
183ffd2:0:b6::/48ffd2:0:b6:ffff:ffff:ffff:ffff:ffff
184ffd2:0:b7::/48ffd2:0:b7:ffff:ffff:ffff:ffff:ffff
185ffd2:0:b8::/48ffd2:0:b8:ffff:ffff:ffff:ffff:ffff
186ffd2:0:b9::/48ffd2:0:b9:ffff:ffff:ffff:ffff:ffff
187ffd2:0:ba::/48ffd2:0:ba:ffff:ffff:ffff:ffff:ffff
188ffd2:0:bb::/48ffd2:0:bb:ffff:ffff:ffff:ffff:ffff
189ffd2:0:bc::/48ffd2:0:bc:ffff:ffff:ffff:ffff:ffff
190ffd2:0:bd::/48ffd2:0:bd:ffff:ffff:ffff:ffff:ffff
191ffd2:0:be::/48ffd2:0:be:ffff:ffff:ffff:ffff:ffff
192ffd2:0:bf::/48ffd2:0:bf:ffff:ffff:ffff:ffff:ffff
193ffd2:0:c0::/48ffd2:0:c0:ffff:ffff:ffff:ffff:ffff
194ffd2:0:c1::/48ffd2:0:c1:ffff:ffff:ffff:ffff:ffff
195ffd2:0:c2::/48ffd2:0:c2:ffff:ffff:ffff:ffff:ffff
196ffd2:0:c3::/48ffd2:0:c3:ffff:ffff:ffff:ffff:ffff
197ffd2:0:c4::/48ffd2:0:c4:ffff:ffff:ffff:ffff:ffff
198ffd2:0:c5::/48ffd2:0:c5:ffff:ffff:ffff:ffff:ffff
199ffd2:0:c6::/48ffd2:0:c6:ffff:ffff:ffff:ffff:ffff
200ffd2:0:c7::/48ffd2:0:c7:ffff:ffff:ffff:ffff:ffff
201ffd2:0:c8::/48ffd2:0:c8:ffff:ffff:ffff:ffff:ffff
202ffd2:0:c9::/48ffd2:0:c9:ffff:ffff:ffff:ffff:ffff
203ffd2:0:ca::/48ffd2:0:ca:ffff:ffff:ffff:ffff:ffff
204ffd2:0:cb::/48ffd2:0:cb:ffff:ffff:ffff:ffff:ffff
205ffd2:0:cc::/48ffd2:0:cc:ffff:ffff:ffff:ffff:ffff
206ffd2:0:cd::/48ffd2:0:cd:ffff:ffff:ffff:ffff:ffff
207ffd2:0:ce::/48ffd2:0:ce:ffff:ffff:ffff:ffff:ffff
208ffd2:0:cf::/48ffd2:0:cf:ffff:ffff:ffff:ffff:ffff
209ffd2:0:d0::/48ffd2:0:d0:ffff:ffff:ffff:ffff:ffff
210ffd2:0:d1::/48ffd2:0:d1:ffff:ffff:ffff:ffff:ffff
211ffd2:0:d2::/48ffd2:0:d2:ffff:ffff:ffff:ffff:ffff
212ffd2:0:d3::/48ffd2:0:d3:ffff:ffff:ffff:ffff:ffff
213ffd2:0:d4::/48ffd2:0:d4:ffff:ffff:ffff:ffff:ffff
214ffd2:0:d5::/48ffd2:0:d5:ffff:ffff:ffff:ffff:ffff
215ffd2:0:d6::/48ffd2:0:d6:ffff:ffff:ffff:ffff:ffff
216ffd2:0:d7::/48ffd2:0:d7:ffff:ffff:ffff:ffff:ffff
217ffd2:0:d8::/48ffd2:0:d8:ffff:ffff:ffff:ffff:ffff
218ffd2:0:d9::/48ffd2:0:d9:ffff:ffff:ffff:ffff:ffff
219ffd2:0:da::/48ffd2:0:da:ffff:ffff:ffff:ffff:ffff
220ffd2:0:db::/48ffd2:0:db:ffff:ffff:ffff:ffff:ffff
221ffd2:0:dc::/48ffd2:0:dc:ffff:ffff:ffff:ffff:ffff
222ffd2:0:dd::/48ffd2:0:dd:ffff:ffff:ffff:ffff:ffff
223ffd2:0:de::/48ffd2:0:de:ffff:ffff:ffff:ffff:ffff
224ffd2:0:df::/48ffd2:0:df:ffff:ffff:ffff:ffff:ffff
225ffd2:0:e0::/48ffd2:0:e0:ffff:ffff:ffff:ffff:ffff
226ffd2:0:e1::/48ffd2:0:e1:ffff:ffff:ffff:ffff:ffff
227ffd2:0:e2::/48ffd2:0:e2:ffff:ffff:ffff:ffff:ffff
228ffd2:0:e3::/48ffd2:0:e3:ffff:ffff:ffff:ffff:ffff
229ffd2:0:e4::/48ffd2:0:e4:ffff:ffff:ffff:ffff:ffff
230ffd2:0:e5::/48ffd2:0:e5:ffff:ffff:ffff:ffff:ffff
231ffd2:0:e6::/48ffd2:0:e6:ffff:ffff:ffff:ffff:ffff
232ffd2:0:e7::/48ffd2:0:e7:ffff:ffff:ffff:ffff:ffff
233ffd2:0:e8::/48ffd2:0:e8:ffff:ffff:ffff:ffff:ffff
234ffd2:0:e9::/48ffd2:0:e9:ffff:ffff:ffff:ffff:ffff
235ffd2:0:ea::/48ffd2:0:ea:ffff:ffff:ffff:ffff:ffff
236ffd2:0:eb::/48ffd2:0:eb:ffff:ffff:ffff:ffff:ffff
237ffd2:0:ec::/48ffd2:0:ec:ffff:ffff:ffff:ffff:ffff
238ffd2:0:ed::/48ffd2:0:ed:ffff:ffff:ffff:ffff:ffff
239ffd2:0:ee::/48ffd2:0:ee:ffff:ffff:ffff:ffff:ffff
240ffd2:0:ef::/48ffd2:0:ef:ffff:ffff:ffff:ffff:ffff
241ffd2:0:f0::/48ffd2:0:f0:ffff:ffff:ffff:ffff:ffff
242ffd2:0:f1::/48ffd2:0:f1:ffff:ffff:ffff:ffff:ffff
243ffd2:0:f2::/48ffd2:0:f2:ffff:ffff:ffff:ffff:ffff
244ffd2:0:f3::/48ffd2:0:f3:ffff:ffff:ffff:ffff:ffff
245ffd2:0:f4::/48ffd2:0:f4:ffff:ffff:ffff:ffff:ffff
246ffd2:0:f5::/48ffd2:0:f5:ffff:ffff:ffff:ffff:ffff
247ffd2:0:f6::/48ffd2:0:f6:ffff:ffff:ffff:ffff:ffff
248ffd2:0:f7::/48ffd2:0:f7:ffff:ffff:ffff:ffff:ffff
249ffd2:0:f8::/48ffd2:0:f8:ffff:ffff:ffff:ffff:ffff
250ffd2:0:f9::/48ffd2:0:f9:ffff:ffff:ffff:ffff:ffff
251ffd2:0:fa::/48ffd2:0:fa:ffff:ffff:ffff:ffff:ffff
252ffd2:0:fb::/48ffd2:0:fb:ffff:ffff:ffff:ffff:ffff
253ffd2:0:fc::/48ffd2:0:fc:ffff:ffff:ffff:ffff:ffff
254ffd2:0:fd::/48ffd2:0:fd:ffff:ffff:ffff:ffff:ffff
255ffd2:0:fe::/48ffd2:0:fe:ffff:ffff:ffff:ffff:ffff
256ffd2:0:ff::/48ffd2:0:ff: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.