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.

Network58.232.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
58.232.0.0
Broadcast address
58.232.255.255
First usable
58.232.0.1
Last usable
58.232.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 3AE80000 · Integer 988282880 to 988348415
Reverse DNS zone
232.58.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111010.11101000..00000000.0000000058.232.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00111010.11101000..00000000.0000000058.232.0.0
Broadcast00111010.11101000..11111111.1111111158.232.255.255
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

58.232.0.0/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
158.232.0.0/2858.232.0.1 to 58.232.0.1458.232.0.1514
258.232.0.16/2858.232.0.17 to 58.232.0.3058.232.0.3114
358.232.0.32/2858.232.0.33 to 58.232.0.4658.232.0.4714
458.232.0.48/2858.232.0.49 to 58.232.0.6258.232.0.6314
558.232.0.64/2858.232.0.65 to 58.232.0.7858.232.0.7914
658.232.0.80/2858.232.0.81 to 58.232.0.9458.232.0.9514
758.232.0.96/2858.232.0.97 to 58.232.0.11058.232.0.11114
858.232.0.112/2858.232.0.113 to 58.232.0.12658.232.0.12714
958.232.0.128/2858.232.0.129 to 58.232.0.14258.232.0.14314
1058.232.0.144/2858.232.0.145 to 58.232.0.15858.232.0.15914
1158.232.0.160/2858.232.0.161 to 58.232.0.17458.232.0.17514
1258.232.0.176/2858.232.0.177 to 58.232.0.19058.232.0.19114
1358.232.0.192/2858.232.0.193 to 58.232.0.20658.232.0.20714
1458.232.0.208/2858.232.0.209 to 58.232.0.22258.232.0.22314
1558.232.0.224/2858.232.0.225 to 58.232.0.23858.232.0.23914
1658.232.0.240/2858.232.0.241 to 58.232.0.25458.232.0.25514
1758.232.1.0/2858.232.1.1 to 58.232.1.1458.232.1.1514
1858.232.1.16/2858.232.1.17 to 58.232.1.3058.232.1.3114
1958.232.1.32/2858.232.1.33 to 58.232.1.4658.232.1.4714
2058.232.1.48/2858.232.1.49 to 58.232.1.6258.232.1.6314
2158.232.1.64/2858.232.1.65 to 58.232.1.7858.232.1.7914
2258.232.1.80/2858.232.1.81 to 58.232.1.9458.232.1.9514
2358.232.1.96/2858.232.1.97 to 58.232.1.11058.232.1.11114
2458.232.1.112/2858.232.1.113 to 58.232.1.12658.232.1.12714
2558.232.1.128/2858.232.1.129 to 58.232.1.14258.232.1.14314
2658.232.1.144/2858.232.1.145 to 58.232.1.15858.232.1.15914
2758.232.1.160/2858.232.1.161 to 58.232.1.17458.232.1.17514
2858.232.1.176/2858.232.1.177 to 58.232.1.19058.232.1.19114
2958.232.1.192/2858.232.1.193 to 58.232.1.20658.232.1.20714
3058.232.1.208/2858.232.1.209 to 58.232.1.22258.232.1.22314
3158.232.1.224/2858.232.1.225 to 58.232.1.23858.232.1.23914
3258.232.1.240/2858.232.1.241 to 58.232.1.25458.232.1.25514
3358.232.2.0/2858.232.2.1 to 58.232.2.1458.232.2.1514
3458.232.2.16/2858.232.2.17 to 58.232.2.3058.232.2.3114
3558.232.2.32/2858.232.2.33 to 58.232.2.4658.232.2.4714
3658.232.2.48/2858.232.2.49 to 58.232.2.6258.232.2.6314
3758.232.2.64/2858.232.2.65 to 58.232.2.7858.232.2.7914
3858.232.2.80/2858.232.2.81 to 58.232.2.9458.232.2.9514
3958.232.2.96/2858.232.2.97 to 58.232.2.11058.232.2.11114
4058.232.2.112/2858.232.2.113 to 58.232.2.12658.232.2.12714
4158.232.2.128/2858.232.2.129 to 58.232.2.14258.232.2.14314
4258.232.2.144/2858.232.2.145 to 58.232.2.15858.232.2.15914
4358.232.2.160/2858.232.2.161 to 58.232.2.17458.232.2.17514
4458.232.2.176/2858.232.2.177 to 58.232.2.19058.232.2.19114
4558.232.2.192/2858.232.2.193 to 58.232.2.20658.232.2.20714
4658.232.2.208/2858.232.2.209 to 58.232.2.22258.232.2.22314
4758.232.2.224/2858.232.2.225 to 58.232.2.23858.232.2.23914
4858.232.2.240/2858.232.2.241 to 58.232.2.25458.232.2.25514
4958.232.3.0/2858.232.3.1 to 58.232.3.1458.232.3.1514
5058.232.3.16/2858.232.3.17 to 58.232.3.3058.232.3.3114
5158.232.3.32/2858.232.3.33 to 58.232.3.4658.232.3.4714
5258.232.3.48/2858.232.3.49 to 58.232.3.6258.232.3.6314
5358.232.3.64/2858.232.3.65 to 58.232.3.7858.232.3.7914
5458.232.3.80/2858.232.3.81 to 58.232.3.9458.232.3.9514
5558.232.3.96/2858.232.3.97 to 58.232.3.11058.232.3.11114
5658.232.3.112/2858.232.3.113 to 58.232.3.12658.232.3.12714
5758.232.3.128/2858.232.3.129 to 58.232.3.14258.232.3.14314
5858.232.3.144/2858.232.3.145 to 58.232.3.15858.232.3.15914
5958.232.3.160/2858.232.3.161 to 58.232.3.17458.232.3.17514
6058.232.3.176/2858.232.3.177 to 58.232.3.19058.232.3.19114
6158.232.3.192/2858.232.3.193 to 58.232.3.20658.232.3.20714
6258.232.3.208/2858.232.3.209 to 58.232.3.22258.232.3.22314
6358.232.3.224/2858.232.3.225 to 58.232.3.23858.232.3.23914
6458.232.3.240/2858.232.3.241 to 58.232.3.25458.232.3.25514
6558.232.4.0/2858.232.4.1 to 58.232.4.1458.232.4.1514
6658.232.4.16/2858.232.4.17 to 58.232.4.3058.232.4.3114
6758.232.4.32/2858.232.4.33 to 58.232.4.4658.232.4.4714
6858.232.4.48/2858.232.4.49 to 58.232.4.6258.232.4.6314
6958.232.4.64/2858.232.4.65 to 58.232.4.7858.232.4.7914
7058.232.4.80/2858.232.4.81 to 58.232.4.9458.232.4.9514
7158.232.4.96/2858.232.4.97 to 58.232.4.11058.232.4.11114
7258.232.4.112/2858.232.4.113 to 58.232.4.12658.232.4.12714
7358.232.4.128/2858.232.4.129 to 58.232.4.14258.232.4.14314
7458.232.4.144/2858.232.4.145 to 58.232.4.15858.232.4.15914
7558.232.4.160/2858.232.4.161 to 58.232.4.17458.232.4.17514
7658.232.4.176/2858.232.4.177 to 58.232.4.19058.232.4.19114
7758.232.4.192/2858.232.4.193 to 58.232.4.20658.232.4.20714
7858.232.4.208/2858.232.4.209 to 58.232.4.22258.232.4.22314
7958.232.4.224/2858.232.4.225 to 58.232.4.23858.232.4.23914
8058.232.4.240/2858.232.4.241 to 58.232.4.25458.232.4.25514
8158.232.5.0/2858.232.5.1 to 58.232.5.1458.232.5.1514
8258.232.5.16/2858.232.5.17 to 58.232.5.3058.232.5.3114
8358.232.5.32/2858.232.5.33 to 58.232.5.4658.232.5.4714
8458.232.5.48/2858.232.5.49 to 58.232.5.6258.232.5.6314
8558.232.5.64/2858.232.5.65 to 58.232.5.7858.232.5.7914
8658.232.5.80/2858.232.5.81 to 58.232.5.9458.232.5.9514
8758.232.5.96/2858.232.5.97 to 58.232.5.11058.232.5.11114
8858.232.5.112/2858.232.5.113 to 58.232.5.12658.232.5.12714
8958.232.5.128/2858.232.5.129 to 58.232.5.14258.232.5.14314
9058.232.5.144/2858.232.5.145 to 58.232.5.15858.232.5.15914
9158.232.5.160/2858.232.5.161 to 58.232.5.17458.232.5.17514
9258.232.5.176/2858.232.5.177 to 58.232.5.19058.232.5.19114
9358.232.5.192/2858.232.5.193 to 58.232.5.20658.232.5.20714
9458.232.5.208/2858.232.5.209 to 58.232.5.22258.232.5.22314
9558.232.5.224/2858.232.5.225 to 58.232.5.23858.232.5.23914
9658.232.5.240/2858.232.5.241 to 58.232.5.25458.232.5.25514
9758.232.6.0/2858.232.6.1 to 58.232.6.1458.232.6.1514
9858.232.6.16/2858.232.6.17 to 58.232.6.3058.232.6.3114
9958.232.6.32/2858.232.6.33 to 58.232.6.4658.232.6.4714
10058.232.6.48/2858.232.6.49 to 58.232.6.6258.232.6.6314
10158.232.6.64/2858.232.6.65 to 58.232.6.7858.232.6.7914
10258.232.6.80/2858.232.6.81 to 58.232.6.9458.232.6.9514
10358.232.6.96/2858.232.6.97 to 58.232.6.11058.232.6.11114
10458.232.6.112/2858.232.6.113 to 58.232.6.12658.232.6.12714
10558.232.6.128/2858.232.6.129 to 58.232.6.14258.232.6.14314
10658.232.6.144/2858.232.6.145 to 58.232.6.15858.232.6.15914
10758.232.6.160/2858.232.6.161 to 58.232.6.17458.232.6.17514
10858.232.6.176/2858.232.6.177 to 58.232.6.19058.232.6.19114
10958.232.6.192/2858.232.6.193 to 58.232.6.20658.232.6.20714
11058.232.6.208/2858.232.6.209 to 58.232.6.22258.232.6.22314
11158.232.6.224/2858.232.6.225 to 58.232.6.23858.232.6.23914
11258.232.6.240/2858.232.6.241 to 58.232.6.25458.232.6.25514
11358.232.7.0/2858.232.7.1 to 58.232.7.1458.232.7.1514
11458.232.7.16/2858.232.7.17 to 58.232.7.3058.232.7.3114
11558.232.7.32/2858.232.7.33 to 58.232.7.4658.232.7.4714
11658.232.7.48/2858.232.7.49 to 58.232.7.6258.232.7.6314
11758.232.7.64/2858.232.7.65 to 58.232.7.7858.232.7.7914
11858.232.7.80/2858.232.7.81 to 58.232.7.9458.232.7.9514
11958.232.7.96/2858.232.7.97 to 58.232.7.11058.232.7.11114
12058.232.7.112/2858.232.7.113 to 58.232.7.12658.232.7.12714
12158.232.7.128/2858.232.7.129 to 58.232.7.14258.232.7.14314
12258.232.7.144/2858.232.7.145 to 58.232.7.15858.232.7.15914
12358.232.7.160/2858.232.7.161 to 58.232.7.17458.232.7.17514
12458.232.7.176/2858.232.7.177 to 58.232.7.19058.232.7.19114
12558.232.7.192/2858.232.7.193 to 58.232.7.20658.232.7.20714
12658.232.7.208/2858.232.7.209 to 58.232.7.22258.232.7.22314
12758.232.7.224/2858.232.7.225 to 58.232.7.23858.232.7.23914
12858.232.7.240/2858.232.7.241 to 58.232.7.25458.232.7.25514
12958.232.8.0/2858.232.8.1 to 58.232.8.1458.232.8.1514
13058.232.8.16/2858.232.8.17 to 58.232.8.3058.232.8.3114
13158.232.8.32/2858.232.8.33 to 58.232.8.4658.232.8.4714
13258.232.8.48/2858.232.8.49 to 58.232.8.6258.232.8.6314
13358.232.8.64/2858.232.8.65 to 58.232.8.7858.232.8.7914
13458.232.8.80/2858.232.8.81 to 58.232.8.9458.232.8.9514
13558.232.8.96/2858.232.8.97 to 58.232.8.11058.232.8.11114
13658.232.8.112/2858.232.8.113 to 58.232.8.12658.232.8.12714
13758.232.8.128/2858.232.8.129 to 58.232.8.14258.232.8.14314
13858.232.8.144/2858.232.8.145 to 58.232.8.15858.232.8.15914
13958.232.8.160/2858.232.8.161 to 58.232.8.17458.232.8.17514
14058.232.8.176/2858.232.8.177 to 58.232.8.19058.232.8.19114
14158.232.8.192/2858.232.8.193 to 58.232.8.20658.232.8.20714
14258.232.8.208/2858.232.8.209 to 58.232.8.22258.232.8.22314
14358.232.8.224/2858.232.8.225 to 58.232.8.23858.232.8.23914
14458.232.8.240/2858.232.8.241 to 58.232.8.25458.232.8.25514
14558.232.9.0/2858.232.9.1 to 58.232.9.1458.232.9.1514
14658.232.9.16/2858.232.9.17 to 58.232.9.3058.232.9.3114
14758.232.9.32/2858.232.9.33 to 58.232.9.4658.232.9.4714
14858.232.9.48/2858.232.9.49 to 58.232.9.6258.232.9.6314
14958.232.9.64/2858.232.9.65 to 58.232.9.7858.232.9.7914
15058.232.9.80/2858.232.9.81 to 58.232.9.9458.232.9.9514
15158.232.9.96/2858.232.9.97 to 58.232.9.11058.232.9.11114
15258.232.9.112/2858.232.9.113 to 58.232.9.12658.232.9.12714
15358.232.9.128/2858.232.9.129 to 58.232.9.14258.232.9.14314
15458.232.9.144/2858.232.9.145 to 58.232.9.15858.232.9.15914
15558.232.9.160/2858.232.9.161 to 58.232.9.17458.232.9.17514
15658.232.9.176/2858.232.9.177 to 58.232.9.19058.232.9.19114
15758.232.9.192/2858.232.9.193 to 58.232.9.20658.232.9.20714
15858.232.9.208/2858.232.9.209 to 58.232.9.22258.232.9.22314
15958.232.9.224/2858.232.9.225 to 58.232.9.23858.232.9.23914
16058.232.9.240/2858.232.9.241 to 58.232.9.25458.232.9.25514
16158.232.10.0/2858.232.10.1 to 58.232.10.1458.232.10.1514
16258.232.10.16/2858.232.10.17 to 58.232.10.3058.232.10.3114
16358.232.10.32/2858.232.10.33 to 58.232.10.4658.232.10.4714
16458.232.10.48/2858.232.10.49 to 58.232.10.6258.232.10.6314
16558.232.10.64/2858.232.10.65 to 58.232.10.7858.232.10.7914
16658.232.10.80/2858.232.10.81 to 58.232.10.9458.232.10.9514
16758.232.10.96/2858.232.10.97 to 58.232.10.11058.232.10.11114
16858.232.10.112/2858.232.10.113 to 58.232.10.12658.232.10.12714
16958.232.10.128/2858.232.10.129 to 58.232.10.14258.232.10.14314
17058.232.10.144/2858.232.10.145 to 58.232.10.15858.232.10.15914
17158.232.10.160/2858.232.10.161 to 58.232.10.17458.232.10.17514
17258.232.10.176/2858.232.10.177 to 58.232.10.19058.232.10.19114
17358.232.10.192/2858.232.10.193 to 58.232.10.20658.232.10.20714
17458.232.10.208/2858.232.10.209 to 58.232.10.22258.232.10.22314
17558.232.10.224/2858.232.10.225 to 58.232.10.23858.232.10.23914
17658.232.10.240/2858.232.10.241 to 58.232.10.25458.232.10.25514
17758.232.11.0/2858.232.11.1 to 58.232.11.1458.232.11.1514
17858.232.11.16/2858.232.11.17 to 58.232.11.3058.232.11.3114
17958.232.11.32/2858.232.11.33 to 58.232.11.4658.232.11.4714
18058.232.11.48/2858.232.11.49 to 58.232.11.6258.232.11.6314
18158.232.11.64/2858.232.11.65 to 58.232.11.7858.232.11.7914
18258.232.11.80/2858.232.11.81 to 58.232.11.9458.232.11.9514
18358.232.11.96/2858.232.11.97 to 58.232.11.11058.232.11.11114
18458.232.11.112/2858.232.11.113 to 58.232.11.12658.232.11.12714
18558.232.11.128/2858.232.11.129 to 58.232.11.14258.232.11.14314
18658.232.11.144/2858.232.11.145 to 58.232.11.15858.232.11.15914
18758.232.11.160/2858.232.11.161 to 58.232.11.17458.232.11.17514
18858.232.11.176/2858.232.11.177 to 58.232.11.19058.232.11.19114
18958.232.11.192/2858.232.11.193 to 58.232.11.20658.232.11.20714
19058.232.11.208/2858.232.11.209 to 58.232.11.22258.232.11.22314
19158.232.11.224/2858.232.11.225 to 58.232.11.23858.232.11.23914
19258.232.11.240/2858.232.11.241 to 58.232.11.25458.232.11.25514
19358.232.12.0/2858.232.12.1 to 58.232.12.1458.232.12.1514
19458.232.12.16/2858.232.12.17 to 58.232.12.3058.232.12.3114
19558.232.12.32/2858.232.12.33 to 58.232.12.4658.232.12.4714
19658.232.12.48/2858.232.12.49 to 58.232.12.6258.232.12.6314
19758.232.12.64/2858.232.12.65 to 58.232.12.7858.232.12.7914
19858.232.12.80/2858.232.12.81 to 58.232.12.9458.232.12.9514
19958.232.12.96/2858.232.12.97 to 58.232.12.11058.232.12.11114
20058.232.12.112/2858.232.12.113 to 58.232.12.12658.232.12.12714
20158.232.12.128/2858.232.12.129 to 58.232.12.14258.232.12.14314
20258.232.12.144/2858.232.12.145 to 58.232.12.15858.232.12.15914
20358.232.12.160/2858.232.12.161 to 58.232.12.17458.232.12.17514
20458.232.12.176/2858.232.12.177 to 58.232.12.19058.232.12.19114
20558.232.12.192/2858.232.12.193 to 58.232.12.20658.232.12.20714
20658.232.12.208/2858.232.12.209 to 58.232.12.22258.232.12.22314
20758.232.12.224/2858.232.12.225 to 58.232.12.23858.232.12.23914
20858.232.12.240/2858.232.12.241 to 58.232.12.25458.232.12.25514
20958.232.13.0/2858.232.13.1 to 58.232.13.1458.232.13.1514
21058.232.13.16/2858.232.13.17 to 58.232.13.3058.232.13.3114
21158.232.13.32/2858.232.13.33 to 58.232.13.4658.232.13.4714
21258.232.13.48/2858.232.13.49 to 58.232.13.6258.232.13.6314
21358.232.13.64/2858.232.13.65 to 58.232.13.7858.232.13.7914
21458.232.13.80/2858.232.13.81 to 58.232.13.9458.232.13.9514
21558.232.13.96/2858.232.13.97 to 58.232.13.11058.232.13.11114
21658.232.13.112/2858.232.13.113 to 58.232.13.12658.232.13.12714
21758.232.13.128/2858.232.13.129 to 58.232.13.14258.232.13.14314
21858.232.13.144/2858.232.13.145 to 58.232.13.15858.232.13.15914
21958.232.13.160/2858.232.13.161 to 58.232.13.17458.232.13.17514
22058.232.13.176/2858.232.13.177 to 58.232.13.19058.232.13.19114
22158.232.13.192/2858.232.13.193 to 58.232.13.20658.232.13.20714
22258.232.13.208/2858.232.13.209 to 58.232.13.22258.232.13.22314
22358.232.13.224/2858.232.13.225 to 58.232.13.23858.232.13.23914
22458.232.13.240/2858.232.13.241 to 58.232.13.25458.232.13.25514
22558.232.14.0/2858.232.14.1 to 58.232.14.1458.232.14.1514
22658.232.14.16/2858.232.14.17 to 58.232.14.3058.232.14.3114
22758.232.14.32/2858.232.14.33 to 58.232.14.4658.232.14.4714
22858.232.14.48/2858.232.14.49 to 58.232.14.6258.232.14.6314
22958.232.14.64/2858.232.14.65 to 58.232.14.7858.232.14.7914
23058.232.14.80/2858.232.14.81 to 58.232.14.9458.232.14.9514
23158.232.14.96/2858.232.14.97 to 58.232.14.11058.232.14.11114
23258.232.14.112/2858.232.14.113 to 58.232.14.12658.232.14.12714
23358.232.14.128/2858.232.14.129 to 58.232.14.14258.232.14.14314
23458.232.14.144/2858.232.14.145 to 58.232.14.15858.232.14.15914
23558.232.14.160/2858.232.14.161 to 58.232.14.17458.232.14.17514
23658.232.14.176/2858.232.14.177 to 58.232.14.19058.232.14.19114
23758.232.14.192/2858.232.14.193 to 58.232.14.20658.232.14.20714
23858.232.14.208/2858.232.14.209 to 58.232.14.22258.232.14.22314
23958.232.14.224/2858.232.14.225 to 58.232.14.23858.232.14.23914
24058.232.14.240/2858.232.14.241 to 58.232.14.25458.232.14.25514
24158.232.15.0/2858.232.15.1 to 58.232.15.1458.232.15.1514
24258.232.15.16/2858.232.15.17 to 58.232.15.3058.232.15.3114
24358.232.15.32/2858.232.15.33 to 58.232.15.4658.232.15.4714
24458.232.15.48/2858.232.15.49 to 58.232.15.6258.232.15.6314
24558.232.15.64/2858.232.15.65 to 58.232.15.7858.232.15.7914
24658.232.15.80/2858.232.15.81 to 58.232.15.9458.232.15.9514
24758.232.15.96/2858.232.15.97 to 58.232.15.11058.232.15.11114
24858.232.15.112/2858.232.15.113 to 58.232.15.12658.232.15.12714
24958.232.15.128/2858.232.15.129 to 58.232.15.14258.232.15.14314
25058.232.15.144/2858.232.15.145 to 58.232.15.15858.232.15.15914
25158.232.15.160/2858.232.15.161 to 58.232.15.17458.232.15.17514
25258.232.15.176/2858.232.15.177 to 58.232.15.19058.232.15.19114
25358.232.15.192/2858.232.15.193 to 58.232.15.20658.232.15.20714
25458.232.15.208/2858.232.15.209 to 58.232.15.22258.232.15.22314
25558.232.15.224/2858.232.15.225 to 58.232.15.23858.232.15.23914
25658.232.15.240/2858.232.15.241 to 58.232.15.25458.232.15.25514

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.