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/16
Addresses2^112
/64 networks2^48
Network
ffbe::/16
First address
ffbe::
Last address
ffbe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
ffbe:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
e.b.f.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ffbe::/16 makes 65,536 subnets of /32; the first 256 are listed.

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