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.

Network57.91.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
57.91.0.0
Broadcast address
57.91.127.255
First usable
57.91.0.1
Last usable
57.91.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 395B0000 · Integer 962265088 to 962297855
Reverse DNS zones
0.91.57.in-addr.arpa
1.91.57.in-addr.arpa
2.91.57.in-addr.arpa
3.91.57.in-addr.arpa
4.91.57.in-addr.arpa
5.91.57.in-addr.arpa
6.91.57.in-addr.arpa
7.91.57.in-addr.arpa
8.91.57.in-addr.arpa
9.91.57.in-addr.arpa
10.91.57.in-addr.arpa
11.91.57.in-addr.arpa
12.91.57.in-addr.arpa
13.91.57.in-addr.arpa
14.91.57.in-addr.arpa
15.91.57.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111001.01011011.00000000.0000000057.91.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00111001.01011011.00000000.0000000057.91.0.0
Broadcast00111001.01011011.01111111.1111111157.91.127.255
Split into smaller subnets/26

57.91.0.0/17 makes 512 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.91.0.0/2657.91.0.1 to 57.91.0.6257.91.0.6362
257.91.0.64/2657.91.0.65 to 57.91.0.12657.91.0.12762
357.91.0.128/2657.91.0.129 to 57.91.0.19057.91.0.19162
457.91.0.192/2657.91.0.193 to 57.91.0.25457.91.0.25562
557.91.1.0/2657.91.1.1 to 57.91.1.6257.91.1.6362
657.91.1.64/2657.91.1.65 to 57.91.1.12657.91.1.12762
757.91.1.128/2657.91.1.129 to 57.91.1.19057.91.1.19162
857.91.1.192/2657.91.1.193 to 57.91.1.25457.91.1.25562
957.91.2.0/2657.91.2.1 to 57.91.2.6257.91.2.6362
1057.91.2.64/2657.91.2.65 to 57.91.2.12657.91.2.12762
1157.91.2.128/2657.91.2.129 to 57.91.2.19057.91.2.19162
1257.91.2.192/2657.91.2.193 to 57.91.2.25457.91.2.25562
1357.91.3.0/2657.91.3.1 to 57.91.3.6257.91.3.6362
1457.91.3.64/2657.91.3.65 to 57.91.3.12657.91.3.12762
1557.91.3.128/2657.91.3.129 to 57.91.3.19057.91.3.19162
1657.91.3.192/2657.91.3.193 to 57.91.3.25457.91.3.25562
1757.91.4.0/2657.91.4.1 to 57.91.4.6257.91.4.6362
1857.91.4.64/2657.91.4.65 to 57.91.4.12657.91.4.12762
1957.91.4.128/2657.91.4.129 to 57.91.4.19057.91.4.19162
2057.91.4.192/2657.91.4.193 to 57.91.4.25457.91.4.25562
2157.91.5.0/2657.91.5.1 to 57.91.5.6257.91.5.6362
2257.91.5.64/2657.91.5.65 to 57.91.5.12657.91.5.12762
2357.91.5.128/2657.91.5.129 to 57.91.5.19057.91.5.19162
2457.91.5.192/2657.91.5.193 to 57.91.5.25457.91.5.25562
2557.91.6.0/2657.91.6.1 to 57.91.6.6257.91.6.6362
2657.91.6.64/2657.91.6.65 to 57.91.6.12657.91.6.12762
2757.91.6.128/2657.91.6.129 to 57.91.6.19057.91.6.19162
2857.91.6.192/2657.91.6.193 to 57.91.6.25457.91.6.25562
2957.91.7.0/2657.91.7.1 to 57.91.7.6257.91.7.6362
3057.91.7.64/2657.91.7.65 to 57.91.7.12657.91.7.12762
3157.91.7.128/2657.91.7.129 to 57.91.7.19057.91.7.19162
3257.91.7.192/2657.91.7.193 to 57.91.7.25457.91.7.25562
3357.91.8.0/2657.91.8.1 to 57.91.8.6257.91.8.6362
3457.91.8.64/2657.91.8.65 to 57.91.8.12657.91.8.12762
3557.91.8.128/2657.91.8.129 to 57.91.8.19057.91.8.19162
3657.91.8.192/2657.91.8.193 to 57.91.8.25457.91.8.25562
3757.91.9.0/2657.91.9.1 to 57.91.9.6257.91.9.6362
3857.91.9.64/2657.91.9.65 to 57.91.9.12657.91.9.12762
3957.91.9.128/2657.91.9.129 to 57.91.9.19057.91.9.19162
4057.91.9.192/2657.91.9.193 to 57.91.9.25457.91.9.25562
4157.91.10.0/2657.91.10.1 to 57.91.10.6257.91.10.6362
4257.91.10.64/2657.91.10.65 to 57.91.10.12657.91.10.12762
4357.91.10.128/2657.91.10.129 to 57.91.10.19057.91.10.19162
4457.91.10.192/2657.91.10.193 to 57.91.10.25457.91.10.25562
4557.91.11.0/2657.91.11.1 to 57.91.11.6257.91.11.6362
4657.91.11.64/2657.91.11.65 to 57.91.11.12657.91.11.12762
4757.91.11.128/2657.91.11.129 to 57.91.11.19057.91.11.19162
4857.91.11.192/2657.91.11.193 to 57.91.11.25457.91.11.25562
4957.91.12.0/2657.91.12.1 to 57.91.12.6257.91.12.6362
5057.91.12.64/2657.91.12.65 to 57.91.12.12657.91.12.12762
5157.91.12.128/2657.91.12.129 to 57.91.12.19057.91.12.19162
5257.91.12.192/2657.91.12.193 to 57.91.12.25457.91.12.25562
5357.91.13.0/2657.91.13.1 to 57.91.13.6257.91.13.6362
5457.91.13.64/2657.91.13.65 to 57.91.13.12657.91.13.12762
5557.91.13.128/2657.91.13.129 to 57.91.13.19057.91.13.19162
5657.91.13.192/2657.91.13.193 to 57.91.13.25457.91.13.25562
5757.91.14.0/2657.91.14.1 to 57.91.14.6257.91.14.6362
5857.91.14.64/2657.91.14.65 to 57.91.14.12657.91.14.12762
5957.91.14.128/2657.91.14.129 to 57.91.14.19057.91.14.19162
6057.91.14.192/2657.91.14.193 to 57.91.14.25457.91.14.25562
6157.91.15.0/2657.91.15.1 to 57.91.15.6257.91.15.6362
6257.91.15.64/2657.91.15.65 to 57.91.15.12657.91.15.12762
6357.91.15.128/2657.91.15.129 to 57.91.15.19057.91.15.19162
6457.91.15.192/2657.91.15.193 to 57.91.15.25457.91.15.25562
6557.91.16.0/2657.91.16.1 to 57.91.16.6257.91.16.6362
6657.91.16.64/2657.91.16.65 to 57.91.16.12657.91.16.12762
6757.91.16.128/2657.91.16.129 to 57.91.16.19057.91.16.19162
6857.91.16.192/2657.91.16.193 to 57.91.16.25457.91.16.25562
6957.91.17.0/2657.91.17.1 to 57.91.17.6257.91.17.6362
7057.91.17.64/2657.91.17.65 to 57.91.17.12657.91.17.12762
7157.91.17.128/2657.91.17.129 to 57.91.17.19057.91.17.19162
7257.91.17.192/2657.91.17.193 to 57.91.17.25457.91.17.25562
7357.91.18.0/2657.91.18.1 to 57.91.18.6257.91.18.6362
7457.91.18.64/2657.91.18.65 to 57.91.18.12657.91.18.12762
7557.91.18.128/2657.91.18.129 to 57.91.18.19057.91.18.19162
7657.91.18.192/2657.91.18.193 to 57.91.18.25457.91.18.25562
7757.91.19.0/2657.91.19.1 to 57.91.19.6257.91.19.6362
7857.91.19.64/2657.91.19.65 to 57.91.19.12657.91.19.12762
7957.91.19.128/2657.91.19.129 to 57.91.19.19057.91.19.19162
8057.91.19.192/2657.91.19.193 to 57.91.19.25457.91.19.25562
8157.91.20.0/2657.91.20.1 to 57.91.20.6257.91.20.6362
8257.91.20.64/2657.91.20.65 to 57.91.20.12657.91.20.12762
8357.91.20.128/2657.91.20.129 to 57.91.20.19057.91.20.19162
8457.91.20.192/2657.91.20.193 to 57.91.20.25457.91.20.25562
8557.91.21.0/2657.91.21.1 to 57.91.21.6257.91.21.6362
8657.91.21.64/2657.91.21.65 to 57.91.21.12657.91.21.12762
8757.91.21.128/2657.91.21.129 to 57.91.21.19057.91.21.19162
8857.91.21.192/2657.91.21.193 to 57.91.21.25457.91.21.25562
8957.91.22.0/2657.91.22.1 to 57.91.22.6257.91.22.6362
9057.91.22.64/2657.91.22.65 to 57.91.22.12657.91.22.12762
9157.91.22.128/2657.91.22.129 to 57.91.22.19057.91.22.19162
9257.91.22.192/2657.91.22.193 to 57.91.22.25457.91.22.25562
9357.91.23.0/2657.91.23.1 to 57.91.23.6257.91.23.6362
9457.91.23.64/2657.91.23.65 to 57.91.23.12657.91.23.12762
9557.91.23.128/2657.91.23.129 to 57.91.23.19057.91.23.19162
9657.91.23.192/2657.91.23.193 to 57.91.23.25457.91.23.25562
9757.91.24.0/2657.91.24.1 to 57.91.24.6257.91.24.6362
9857.91.24.64/2657.91.24.65 to 57.91.24.12657.91.24.12762
9957.91.24.128/2657.91.24.129 to 57.91.24.19057.91.24.19162
10057.91.24.192/2657.91.24.193 to 57.91.24.25457.91.24.25562
10157.91.25.0/2657.91.25.1 to 57.91.25.6257.91.25.6362
10257.91.25.64/2657.91.25.65 to 57.91.25.12657.91.25.12762
10357.91.25.128/2657.91.25.129 to 57.91.25.19057.91.25.19162
10457.91.25.192/2657.91.25.193 to 57.91.25.25457.91.25.25562
10557.91.26.0/2657.91.26.1 to 57.91.26.6257.91.26.6362
10657.91.26.64/2657.91.26.65 to 57.91.26.12657.91.26.12762
10757.91.26.128/2657.91.26.129 to 57.91.26.19057.91.26.19162
10857.91.26.192/2657.91.26.193 to 57.91.26.25457.91.26.25562
10957.91.27.0/2657.91.27.1 to 57.91.27.6257.91.27.6362
11057.91.27.64/2657.91.27.65 to 57.91.27.12657.91.27.12762
11157.91.27.128/2657.91.27.129 to 57.91.27.19057.91.27.19162
11257.91.27.192/2657.91.27.193 to 57.91.27.25457.91.27.25562
11357.91.28.0/2657.91.28.1 to 57.91.28.6257.91.28.6362
11457.91.28.64/2657.91.28.65 to 57.91.28.12657.91.28.12762
11557.91.28.128/2657.91.28.129 to 57.91.28.19057.91.28.19162
11657.91.28.192/2657.91.28.193 to 57.91.28.25457.91.28.25562
11757.91.29.0/2657.91.29.1 to 57.91.29.6257.91.29.6362
11857.91.29.64/2657.91.29.65 to 57.91.29.12657.91.29.12762
11957.91.29.128/2657.91.29.129 to 57.91.29.19057.91.29.19162
12057.91.29.192/2657.91.29.193 to 57.91.29.25457.91.29.25562
12157.91.30.0/2657.91.30.1 to 57.91.30.6257.91.30.6362
12257.91.30.64/2657.91.30.65 to 57.91.30.12657.91.30.12762
12357.91.30.128/2657.91.30.129 to 57.91.30.19057.91.30.19162
12457.91.30.192/2657.91.30.193 to 57.91.30.25457.91.30.25562
12557.91.31.0/2657.91.31.1 to 57.91.31.6257.91.31.6362
12657.91.31.64/2657.91.31.65 to 57.91.31.12657.91.31.12762
12757.91.31.128/2657.91.31.129 to 57.91.31.19057.91.31.19162
12857.91.31.192/2657.91.31.193 to 57.91.31.25457.91.31.25562
12957.91.32.0/2657.91.32.1 to 57.91.32.6257.91.32.6362
13057.91.32.64/2657.91.32.65 to 57.91.32.12657.91.32.12762
13157.91.32.128/2657.91.32.129 to 57.91.32.19057.91.32.19162
13257.91.32.192/2657.91.32.193 to 57.91.32.25457.91.32.25562
13357.91.33.0/2657.91.33.1 to 57.91.33.6257.91.33.6362
13457.91.33.64/2657.91.33.65 to 57.91.33.12657.91.33.12762
13557.91.33.128/2657.91.33.129 to 57.91.33.19057.91.33.19162
13657.91.33.192/2657.91.33.193 to 57.91.33.25457.91.33.25562
13757.91.34.0/2657.91.34.1 to 57.91.34.6257.91.34.6362
13857.91.34.64/2657.91.34.65 to 57.91.34.12657.91.34.12762
13957.91.34.128/2657.91.34.129 to 57.91.34.19057.91.34.19162
14057.91.34.192/2657.91.34.193 to 57.91.34.25457.91.34.25562
14157.91.35.0/2657.91.35.1 to 57.91.35.6257.91.35.6362
14257.91.35.64/2657.91.35.65 to 57.91.35.12657.91.35.12762
14357.91.35.128/2657.91.35.129 to 57.91.35.19057.91.35.19162
14457.91.35.192/2657.91.35.193 to 57.91.35.25457.91.35.25562
14557.91.36.0/2657.91.36.1 to 57.91.36.6257.91.36.6362
14657.91.36.64/2657.91.36.65 to 57.91.36.12657.91.36.12762
14757.91.36.128/2657.91.36.129 to 57.91.36.19057.91.36.19162
14857.91.36.192/2657.91.36.193 to 57.91.36.25457.91.36.25562
14957.91.37.0/2657.91.37.1 to 57.91.37.6257.91.37.6362
15057.91.37.64/2657.91.37.65 to 57.91.37.12657.91.37.12762
15157.91.37.128/2657.91.37.129 to 57.91.37.19057.91.37.19162
15257.91.37.192/2657.91.37.193 to 57.91.37.25457.91.37.25562
15357.91.38.0/2657.91.38.1 to 57.91.38.6257.91.38.6362
15457.91.38.64/2657.91.38.65 to 57.91.38.12657.91.38.12762
15557.91.38.128/2657.91.38.129 to 57.91.38.19057.91.38.19162
15657.91.38.192/2657.91.38.193 to 57.91.38.25457.91.38.25562
15757.91.39.0/2657.91.39.1 to 57.91.39.6257.91.39.6362
15857.91.39.64/2657.91.39.65 to 57.91.39.12657.91.39.12762
15957.91.39.128/2657.91.39.129 to 57.91.39.19057.91.39.19162
16057.91.39.192/2657.91.39.193 to 57.91.39.25457.91.39.25562
16157.91.40.0/2657.91.40.1 to 57.91.40.6257.91.40.6362
16257.91.40.64/2657.91.40.65 to 57.91.40.12657.91.40.12762
16357.91.40.128/2657.91.40.129 to 57.91.40.19057.91.40.19162
16457.91.40.192/2657.91.40.193 to 57.91.40.25457.91.40.25562
16557.91.41.0/2657.91.41.1 to 57.91.41.6257.91.41.6362
16657.91.41.64/2657.91.41.65 to 57.91.41.12657.91.41.12762
16757.91.41.128/2657.91.41.129 to 57.91.41.19057.91.41.19162
16857.91.41.192/2657.91.41.193 to 57.91.41.25457.91.41.25562
16957.91.42.0/2657.91.42.1 to 57.91.42.6257.91.42.6362
17057.91.42.64/2657.91.42.65 to 57.91.42.12657.91.42.12762
17157.91.42.128/2657.91.42.129 to 57.91.42.19057.91.42.19162
17257.91.42.192/2657.91.42.193 to 57.91.42.25457.91.42.25562
17357.91.43.0/2657.91.43.1 to 57.91.43.6257.91.43.6362
17457.91.43.64/2657.91.43.65 to 57.91.43.12657.91.43.12762
17557.91.43.128/2657.91.43.129 to 57.91.43.19057.91.43.19162
17657.91.43.192/2657.91.43.193 to 57.91.43.25457.91.43.25562
17757.91.44.0/2657.91.44.1 to 57.91.44.6257.91.44.6362
17857.91.44.64/2657.91.44.65 to 57.91.44.12657.91.44.12762
17957.91.44.128/2657.91.44.129 to 57.91.44.19057.91.44.19162
18057.91.44.192/2657.91.44.193 to 57.91.44.25457.91.44.25562
18157.91.45.0/2657.91.45.1 to 57.91.45.6257.91.45.6362
18257.91.45.64/2657.91.45.65 to 57.91.45.12657.91.45.12762
18357.91.45.128/2657.91.45.129 to 57.91.45.19057.91.45.19162
18457.91.45.192/2657.91.45.193 to 57.91.45.25457.91.45.25562
18557.91.46.0/2657.91.46.1 to 57.91.46.6257.91.46.6362
18657.91.46.64/2657.91.46.65 to 57.91.46.12657.91.46.12762
18757.91.46.128/2657.91.46.129 to 57.91.46.19057.91.46.19162
18857.91.46.192/2657.91.46.193 to 57.91.46.25457.91.46.25562
18957.91.47.0/2657.91.47.1 to 57.91.47.6257.91.47.6362
19057.91.47.64/2657.91.47.65 to 57.91.47.12657.91.47.12762
19157.91.47.128/2657.91.47.129 to 57.91.47.19057.91.47.19162
19257.91.47.192/2657.91.47.193 to 57.91.47.25457.91.47.25562
19357.91.48.0/2657.91.48.1 to 57.91.48.6257.91.48.6362
19457.91.48.64/2657.91.48.65 to 57.91.48.12657.91.48.12762
19557.91.48.128/2657.91.48.129 to 57.91.48.19057.91.48.19162
19657.91.48.192/2657.91.48.193 to 57.91.48.25457.91.48.25562
19757.91.49.0/2657.91.49.1 to 57.91.49.6257.91.49.6362
19857.91.49.64/2657.91.49.65 to 57.91.49.12657.91.49.12762
19957.91.49.128/2657.91.49.129 to 57.91.49.19057.91.49.19162
20057.91.49.192/2657.91.49.193 to 57.91.49.25457.91.49.25562
20157.91.50.0/2657.91.50.1 to 57.91.50.6257.91.50.6362
20257.91.50.64/2657.91.50.65 to 57.91.50.12657.91.50.12762
20357.91.50.128/2657.91.50.129 to 57.91.50.19057.91.50.19162
20457.91.50.192/2657.91.50.193 to 57.91.50.25457.91.50.25562
20557.91.51.0/2657.91.51.1 to 57.91.51.6257.91.51.6362
20657.91.51.64/2657.91.51.65 to 57.91.51.12657.91.51.12762
20757.91.51.128/2657.91.51.129 to 57.91.51.19057.91.51.19162
20857.91.51.192/2657.91.51.193 to 57.91.51.25457.91.51.25562
20957.91.52.0/2657.91.52.1 to 57.91.52.6257.91.52.6362
21057.91.52.64/2657.91.52.65 to 57.91.52.12657.91.52.12762
21157.91.52.128/2657.91.52.129 to 57.91.52.19057.91.52.19162
21257.91.52.192/2657.91.52.193 to 57.91.52.25457.91.52.25562
21357.91.53.0/2657.91.53.1 to 57.91.53.6257.91.53.6362
21457.91.53.64/2657.91.53.65 to 57.91.53.12657.91.53.12762
21557.91.53.128/2657.91.53.129 to 57.91.53.19057.91.53.19162
21657.91.53.192/2657.91.53.193 to 57.91.53.25457.91.53.25562
21757.91.54.0/2657.91.54.1 to 57.91.54.6257.91.54.6362
21857.91.54.64/2657.91.54.65 to 57.91.54.12657.91.54.12762
21957.91.54.128/2657.91.54.129 to 57.91.54.19057.91.54.19162
22057.91.54.192/2657.91.54.193 to 57.91.54.25457.91.54.25562
22157.91.55.0/2657.91.55.1 to 57.91.55.6257.91.55.6362
22257.91.55.64/2657.91.55.65 to 57.91.55.12657.91.55.12762
22357.91.55.128/2657.91.55.129 to 57.91.55.19057.91.55.19162
22457.91.55.192/2657.91.55.193 to 57.91.55.25457.91.55.25562
22557.91.56.0/2657.91.56.1 to 57.91.56.6257.91.56.6362
22657.91.56.64/2657.91.56.65 to 57.91.56.12657.91.56.12762
22757.91.56.128/2657.91.56.129 to 57.91.56.19057.91.56.19162
22857.91.56.192/2657.91.56.193 to 57.91.56.25457.91.56.25562
22957.91.57.0/2657.91.57.1 to 57.91.57.6257.91.57.6362
23057.91.57.64/2657.91.57.65 to 57.91.57.12657.91.57.12762
23157.91.57.128/2657.91.57.129 to 57.91.57.19057.91.57.19162
23257.91.57.192/2657.91.57.193 to 57.91.57.25457.91.57.25562
23357.91.58.0/2657.91.58.1 to 57.91.58.6257.91.58.6362
23457.91.58.64/2657.91.58.65 to 57.91.58.12657.91.58.12762
23557.91.58.128/2657.91.58.129 to 57.91.58.19057.91.58.19162
23657.91.58.192/2657.91.58.193 to 57.91.58.25457.91.58.25562
23757.91.59.0/2657.91.59.1 to 57.91.59.6257.91.59.6362
23857.91.59.64/2657.91.59.65 to 57.91.59.12657.91.59.12762
23957.91.59.128/2657.91.59.129 to 57.91.59.19057.91.59.19162
24057.91.59.192/2657.91.59.193 to 57.91.59.25457.91.59.25562
24157.91.60.0/2657.91.60.1 to 57.91.60.6257.91.60.6362
24257.91.60.64/2657.91.60.65 to 57.91.60.12657.91.60.12762
24357.91.60.128/2657.91.60.129 to 57.91.60.19057.91.60.19162
24457.91.60.192/2657.91.60.193 to 57.91.60.25457.91.60.25562
24557.91.61.0/2657.91.61.1 to 57.91.61.6257.91.61.6362
24657.91.61.64/2657.91.61.65 to 57.91.61.12657.91.61.12762
24757.91.61.128/2657.91.61.129 to 57.91.61.19057.91.61.19162
24857.91.61.192/2657.91.61.193 to 57.91.61.25457.91.61.25562
24957.91.62.0/2657.91.62.1 to 57.91.62.6257.91.62.6362
25057.91.62.64/2657.91.62.65 to 57.91.62.12657.91.62.12762
25157.91.62.128/2657.91.62.129 to 57.91.62.19057.91.62.19162
25257.91.62.192/2657.91.62.193 to 57.91.62.25457.91.62.25562
25357.91.63.0/2657.91.63.1 to 57.91.63.6257.91.63.6362
25457.91.63.64/2657.91.63.65 to 57.91.63.12657.91.63.12762
25557.91.63.128/2657.91.63.129 to 57.91.63.19057.91.63.19162
25657.91.63.192/2657.91.63.193 to 57.91.63.25457.91.63.25562

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