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/120
Addresses256
/64 networksPart of one
Network
2c19:dd:d9:dd:c25:c25:94de:3000/120
First address
2c19:dd:d9:dd:c25:c25:94de:3000
Last address
2c19:dd:d9:dd:c25:c25:94de:30ff
Addresses
256
/64 networks (LANs)
None: smaller than one /64 LAN
Full form
2c19:00dd:00d9:00dd:0c25:0c25:94de:3000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
0.3.e.d.4.9.5.2.c.0.5.2.c.0.d.d.0.0.9.d.0.0.d.d.0.0.9.1.c.2.ip6.arpa
Split into smaller subnets/128
/121 (2)/122 (4)/123 (8)/124 (16)/127 (128)/128 (256)

2c19:dd:d9:dd:c25:c25:94de:3000/120 makes 256 subnets of /128.

Subnets
#SubnetLast address
12c19:dd:d9:dd:c25:c25:94de:3000/1282c19:dd:d9:dd:c25:c25:94de:3000
22c19:dd:d9:dd:c25:c25:94de:3001/1282c19:dd:d9:dd:c25:c25:94de:3001
32c19:dd:d9:dd:c25:c25:94de:3002/1282c19:dd:d9:dd:c25:c25:94de:3002
42c19:dd:d9:dd:c25:c25:94de:3003/1282c19:dd:d9:dd:c25:c25:94de:3003
52c19:dd:d9:dd:c25:c25:94de:3004/1282c19:dd:d9:dd:c25:c25:94de:3004
62c19:dd:d9:dd:c25:c25:94de:3005/1282c19:dd:d9:dd:c25:c25:94de:3005
72c19:dd:d9:dd:c25:c25:94de:3006/1282c19:dd:d9:dd:c25:c25:94de:3006
82c19:dd:d9:dd:c25:c25:94de:3007/1282c19:dd:d9:dd:c25:c25:94de:3007
92c19:dd:d9:dd:c25:c25:94de:3008/1282c19:dd:d9:dd:c25:c25:94de:3008
102c19:dd:d9:dd:c25:c25:94de:3009/1282c19:dd:d9:dd:c25:c25:94de:3009
112c19:dd:d9:dd:c25:c25:94de:300a/1282c19:dd:d9:dd:c25:c25:94de:300a
122c19:dd:d9:dd:c25:c25:94de:300b/1282c19:dd:d9:dd:c25:c25:94de:300b
132c19:dd:d9:dd:c25:c25:94de:300c/1282c19:dd:d9:dd:c25:c25:94de:300c
142c19:dd:d9:dd:c25:c25:94de:300d/1282c19:dd:d9:dd:c25:c25:94de:300d
152c19:dd:d9:dd:c25:c25:94de:300e/1282c19:dd:d9:dd:c25:c25:94de:300e
162c19:dd:d9:dd:c25:c25:94de:300f/1282c19:dd:d9:dd:c25:c25:94de:300f
172c19:dd:d9:dd:c25:c25:94de:3010/1282c19:dd:d9:dd:c25:c25:94de:3010
182c19:dd:d9:dd:c25:c25:94de:3011/1282c19:dd:d9:dd:c25:c25:94de:3011
192c19:dd:d9:dd:c25:c25:94de:3012/1282c19:dd:d9:dd:c25:c25:94de:3012
202c19:dd:d9:dd:c25:c25:94de:3013/1282c19:dd:d9:dd:c25:c25:94de:3013
212c19:dd:d9:dd:c25:c25:94de:3014/1282c19:dd:d9:dd:c25:c25:94de:3014
222c19:dd:d9:dd:c25:c25:94de:3015/1282c19:dd:d9:dd:c25:c25:94de:3015
232c19:dd:d9:dd:c25:c25:94de:3016/1282c19:dd:d9:dd:c25:c25:94de:3016
242c19:dd:d9:dd:c25:c25:94de:3017/1282c19:dd:d9:dd:c25:c25:94de:3017
252c19:dd:d9:dd:c25:c25:94de:3018/1282c19:dd:d9:dd:c25:c25:94de:3018
262c19:dd:d9:dd:c25:c25:94de:3019/1282c19:dd:d9:dd:c25:c25:94de:3019
272c19:dd:d9:dd:c25:c25:94de:301a/1282c19:dd:d9:dd:c25:c25:94de:301a
282c19:dd:d9:dd:c25:c25:94de:301b/1282c19:dd:d9:dd:c25:c25:94de:301b
292c19:dd:d9:dd:c25:c25:94de:301c/1282c19:dd:d9:dd:c25:c25:94de:301c
302c19:dd:d9:dd:c25:c25:94de:301d/1282c19:dd:d9:dd:c25:c25:94de:301d
312c19:dd:d9:dd:c25:c25:94de:301e/1282c19:dd:d9:dd:c25:c25:94de:301e
322c19:dd:d9:dd:c25:c25:94de:301f/1282c19:dd:d9:dd:c25:c25:94de:301f
332c19:dd:d9:dd:c25:c25:94de:3020/1282c19:dd:d9:dd:c25:c25:94de:3020
342c19:dd:d9:dd:c25:c25:94de:3021/1282c19:dd:d9:dd:c25:c25:94de:3021
352c19:dd:d9:dd:c25:c25:94de:3022/1282c19:dd:d9:dd:c25:c25:94de:3022
362c19:dd:d9:dd:c25:c25:94de:3023/1282c19:dd:d9:dd:c25:c25:94de:3023
372c19:dd:d9:dd:c25:c25:94de:3024/1282c19:dd:d9:dd:c25:c25:94de:3024
382c19:dd:d9:dd:c25:c25:94de:3025/1282c19:dd:d9:dd:c25:c25:94de:3025
392c19:dd:d9:dd:c25:c25:94de:3026/1282c19:dd:d9:dd:c25:c25:94de:3026
402c19:dd:d9:dd:c25:c25:94de:3027/1282c19:dd:d9:dd:c25:c25:94de:3027
412c19:dd:d9:dd:c25:c25:94de:3028/1282c19:dd:d9:dd:c25:c25:94de:3028
422c19:dd:d9:dd:c25:c25:94de:3029/1282c19:dd:d9:dd:c25:c25:94de:3029
432c19:dd:d9:dd:c25:c25:94de:302a/1282c19:dd:d9:dd:c25:c25:94de:302a
442c19:dd:d9:dd:c25:c25:94de:302b/1282c19:dd:d9:dd:c25:c25:94de:302b
452c19:dd:d9:dd:c25:c25:94de:302c/1282c19:dd:d9:dd:c25:c25:94de:302c
462c19:dd:d9:dd:c25:c25:94de:302d/1282c19:dd:d9:dd:c25:c25:94de:302d
472c19:dd:d9:dd:c25:c25:94de:302e/1282c19:dd:d9:dd:c25:c25:94de:302e
482c19:dd:d9:dd:c25:c25:94de:302f/1282c19:dd:d9:dd:c25:c25:94de:302f
492c19:dd:d9:dd:c25:c25:94de:3030/1282c19:dd:d9:dd:c25:c25:94de:3030
502c19:dd:d9:dd:c25:c25:94de:3031/1282c19:dd:d9:dd:c25:c25:94de:3031
512c19:dd:d9:dd:c25:c25:94de:3032/1282c19:dd:d9:dd:c25:c25:94de:3032
522c19:dd:d9:dd:c25:c25:94de:3033/1282c19:dd:d9:dd:c25:c25:94de:3033
532c19:dd:d9:dd:c25:c25:94de:3034/1282c19:dd:d9:dd:c25:c25:94de:3034
542c19:dd:d9:dd:c25:c25:94de:3035/1282c19:dd:d9:dd:c25:c25:94de:3035
552c19:dd:d9:dd:c25:c25:94de:3036/1282c19:dd:d9:dd:c25:c25:94de:3036
562c19:dd:d9:dd:c25:c25:94de:3037/1282c19:dd:d9:dd:c25:c25:94de:3037
572c19:dd:d9:dd:c25:c25:94de:3038/1282c19:dd:d9:dd:c25:c25:94de:3038
582c19:dd:d9:dd:c25:c25:94de:3039/1282c19:dd:d9:dd:c25:c25:94de:3039
592c19:dd:d9:dd:c25:c25:94de:303a/1282c19:dd:d9:dd:c25:c25:94de:303a
602c19:dd:d9:dd:c25:c25:94de:303b/1282c19:dd:d9:dd:c25:c25:94de:303b
612c19:dd:d9:dd:c25:c25:94de:303c/1282c19:dd:d9:dd:c25:c25:94de:303c
622c19:dd:d9:dd:c25:c25:94de:303d/1282c19:dd:d9:dd:c25:c25:94de:303d
632c19:dd:d9:dd:c25:c25:94de:303e/1282c19:dd:d9:dd:c25:c25:94de:303e
642c19:dd:d9:dd:c25:c25:94de:303f/1282c19:dd:d9:dd:c25:c25:94de:303f
652c19:dd:d9:dd:c25:c25:94de:3040/1282c19:dd:d9:dd:c25:c25:94de:3040
662c19:dd:d9:dd:c25:c25:94de:3041/1282c19:dd:d9:dd:c25:c25:94de:3041
672c19:dd:d9:dd:c25:c25:94de:3042/1282c19:dd:d9:dd:c25:c25:94de:3042
682c19:dd:d9:dd:c25:c25:94de:3043/1282c19:dd:d9:dd:c25:c25:94de:3043
692c19:dd:d9:dd:c25:c25:94de:3044/1282c19:dd:d9:dd:c25:c25:94de:3044
702c19:dd:d9:dd:c25:c25:94de:3045/1282c19:dd:d9:dd:c25:c25:94de:3045
712c19:dd:d9:dd:c25:c25:94de:3046/1282c19:dd:d9:dd:c25:c25:94de:3046
722c19:dd:d9:dd:c25:c25:94de:3047/1282c19:dd:d9:dd:c25:c25:94de:3047
732c19:dd:d9:dd:c25:c25:94de:3048/1282c19:dd:d9:dd:c25:c25:94de:3048
742c19:dd:d9:dd:c25:c25:94de:3049/1282c19:dd:d9:dd:c25:c25:94de:3049
752c19:dd:d9:dd:c25:c25:94de:304a/1282c19:dd:d9:dd:c25:c25:94de:304a
762c19:dd:d9:dd:c25:c25:94de:304b/1282c19:dd:d9:dd:c25:c25:94de:304b
772c19:dd:d9:dd:c25:c25:94de:304c/1282c19:dd:d9:dd:c25:c25:94de:304c
782c19:dd:d9:dd:c25:c25:94de:304d/1282c19:dd:d9:dd:c25:c25:94de:304d
792c19:dd:d9:dd:c25:c25:94de:304e/1282c19:dd:d9:dd:c25:c25:94de:304e
802c19:dd:d9:dd:c25:c25:94de:304f/1282c19:dd:d9:dd:c25:c25:94de:304f
812c19:dd:d9:dd:c25:c25:94de:3050/1282c19:dd:d9:dd:c25:c25:94de:3050
822c19:dd:d9:dd:c25:c25:94de:3051/1282c19:dd:d9:dd:c25:c25:94de:3051
832c19:dd:d9:dd:c25:c25:94de:3052/1282c19:dd:d9:dd:c25:c25:94de:3052
842c19:dd:d9:dd:c25:c25:94de:3053/1282c19:dd:d9:dd:c25:c25:94de:3053
852c19:dd:d9:dd:c25:c25:94de:3054/1282c19:dd:d9:dd:c25:c25:94de:3054
862c19:dd:d9:dd:c25:c25:94de:3055/1282c19:dd:d9:dd:c25:c25:94de:3055
872c19:dd:d9:dd:c25:c25:94de:3056/1282c19:dd:d9:dd:c25:c25:94de:3056
882c19:dd:d9:dd:c25:c25:94de:3057/1282c19:dd:d9:dd:c25:c25:94de:3057
892c19:dd:d9:dd:c25:c25:94de:3058/1282c19:dd:d9:dd:c25:c25:94de:3058
902c19:dd:d9:dd:c25:c25:94de:3059/1282c19:dd:d9:dd:c25:c25:94de:3059
912c19:dd:d9:dd:c25:c25:94de:305a/1282c19:dd:d9:dd:c25:c25:94de:305a
922c19:dd:d9:dd:c25:c25:94de:305b/1282c19:dd:d9:dd:c25:c25:94de:305b
932c19:dd:d9:dd:c25:c25:94de:305c/1282c19:dd:d9:dd:c25:c25:94de:305c
942c19:dd:d9:dd:c25:c25:94de:305d/1282c19:dd:d9:dd:c25:c25:94de:305d
952c19:dd:d9:dd:c25:c25:94de:305e/1282c19:dd:d9:dd:c25:c25:94de:305e
962c19:dd:d9:dd:c25:c25:94de:305f/1282c19:dd:d9:dd:c25:c25:94de:305f
972c19:dd:d9:dd:c25:c25:94de:3060/1282c19:dd:d9:dd:c25:c25:94de:3060
982c19:dd:d9:dd:c25:c25:94de:3061/1282c19:dd:d9:dd:c25:c25:94de:3061
992c19:dd:d9:dd:c25:c25:94de:3062/1282c19:dd:d9:dd:c25:c25:94de:3062
1002c19:dd:d9:dd:c25:c25:94de:3063/1282c19:dd:d9:dd:c25:c25:94de:3063
1012c19:dd:d9:dd:c25:c25:94de:3064/1282c19:dd:d9:dd:c25:c25:94de:3064
1022c19:dd:d9:dd:c25:c25:94de:3065/1282c19:dd:d9:dd:c25:c25:94de:3065
1032c19:dd:d9:dd:c25:c25:94de:3066/1282c19:dd:d9:dd:c25:c25:94de:3066
1042c19:dd:d9:dd:c25:c25:94de:3067/1282c19:dd:d9:dd:c25:c25:94de:3067
1052c19:dd:d9:dd:c25:c25:94de:3068/1282c19:dd:d9:dd:c25:c25:94de:3068
1062c19:dd:d9:dd:c25:c25:94de:3069/1282c19:dd:d9:dd:c25:c25:94de:3069
1072c19:dd:d9:dd:c25:c25:94de:306a/1282c19:dd:d9:dd:c25:c25:94de:306a
1082c19:dd:d9:dd:c25:c25:94de:306b/1282c19:dd:d9:dd:c25:c25:94de:306b
1092c19:dd:d9:dd:c25:c25:94de:306c/1282c19:dd:d9:dd:c25:c25:94de:306c
1102c19:dd:d9:dd:c25:c25:94de:306d/1282c19:dd:d9:dd:c25:c25:94de:306d
1112c19:dd:d9:dd:c25:c25:94de:306e/1282c19:dd:d9:dd:c25:c25:94de:306e
1122c19:dd:d9:dd:c25:c25:94de:306f/1282c19:dd:d9:dd:c25:c25:94de:306f
1132c19:dd:d9:dd:c25:c25:94de:3070/1282c19:dd:d9:dd:c25:c25:94de:3070
1142c19:dd:d9:dd:c25:c25:94de:3071/1282c19:dd:d9:dd:c25:c25:94de:3071
1152c19:dd:d9:dd:c25:c25:94de:3072/1282c19:dd:d9:dd:c25:c25:94de:3072
1162c19:dd:d9:dd:c25:c25:94de:3073/1282c19:dd:d9:dd:c25:c25:94de:3073
1172c19:dd:d9:dd:c25:c25:94de:3074/1282c19:dd:d9:dd:c25:c25:94de:3074
1182c19:dd:d9:dd:c25:c25:94de:3075/1282c19:dd:d9:dd:c25:c25:94de:3075
1192c19:dd:d9:dd:c25:c25:94de:3076/1282c19:dd:d9:dd:c25:c25:94de:3076
1202c19:dd:d9:dd:c25:c25:94de:3077/1282c19:dd:d9:dd:c25:c25:94de:3077
1212c19:dd:d9:dd:c25:c25:94de:3078/1282c19:dd:d9:dd:c25:c25:94de:3078
1222c19:dd:d9:dd:c25:c25:94de:3079/1282c19:dd:d9:dd:c25:c25:94de:3079
1232c19:dd:d9:dd:c25:c25:94de:307a/1282c19:dd:d9:dd:c25:c25:94de:307a
1242c19:dd:d9:dd:c25:c25:94de:307b/1282c19:dd:d9:dd:c25:c25:94de:307b
1252c19:dd:d9:dd:c25:c25:94de:307c/1282c19:dd:d9:dd:c25:c25:94de:307c
1262c19:dd:d9:dd:c25:c25:94de:307d/1282c19:dd:d9:dd:c25:c25:94de:307d
1272c19:dd:d9:dd:c25:c25:94de:307e/1282c19:dd:d9:dd:c25:c25:94de:307e
1282c19:dd:d9:dd:c25:c25:94de:307f/1282c19:dd:d9:dd:c25:c25:94de:307f
1292c19:dd:d9:dd:c25:c25:94de:3080/1282c19:dd:d9:dd:c25:c25:94de:3080
1302c19:dd:d9:dd:c25:c25:94de:3081/1282c19:dd:d9:dd:c25:c25:94de:3081
1312c19:dd:d9:dd:c25:c25:94de:3082/1282c19:dd:d9:dd:c25:c25:94de:3082
1322c19:dd:d9:dd:c25:c25:94de:3083/1282c19:dd:d9:dd:c25:c25:94de:3083
1332c19:dd:d9:dd:c25:c25:94de:3084/1282c19:dd:d9:dd:c25:c25:94de:3084
1342c19:dd:d9:dd:c25:c25:94de:3085/1282c19:dd:d9:dd:c25:c25:94de:3085
1352c19:dd:d9:dd:c25:c25:94de:3086/1282c19:dd:d9:dd:c25:c25:94de:3086
1362c19:dd:d9:dd:c25:c25:94de:3087/1282c19:dd:d9:dd:c25:c25:94de:3087
1372c19:dd:d9:dd:c25:c25:94de:3088/1282c19:dd:d9:dd:c25:c25:94de:3088
1382c19:dd:d9:dd:c25:c25:94de:3089/1282c19:dd:d9:dd:c25:c25:94de:3089
1392c19:dd:d9:dd:c25:c25:94de:308a/1282c19:dd:d9:dd:c25:c25:94de:308a
1402c19:dd:d9:dd:c25:c25:94de:308b/1282c19:dd:d9:dd:c25:c25:94de:308b
1412c19:dd:d9:dd:c25:c25:94de:308c/1282c19:dd:d9:dd:c25:c25:94de:308c
1422c19:dd:d9:dd:c25:c25:94de:308d/1282c19:dd:d9:dd:c25:c25:94de:308d
1432c19:dd:d9:dd:c25:c25:94de:308e/1282c19:dd:d9:dd:c25:c25:94de:308e
1442c19:dd:d9:dd:c25:c25:94de:308f/1282c19:dd:d9:dd:c25:c25:94de:308f
1452c19:dd:d9:dd:c25:c25:94de:3090/1282c19:dd:d9:dd:c25:c25:94de:3090
1462c19:dd:d9:dd:c25:c25:94de:3091/1282c19:dd:d9:dd:c25:c25:94de:3091
1472c19:dd:d9:dd:c25:c25:94de:3092/1282c19:dd:d9:dd:c25:c25:94de:3092
1482c19:dd:d9:dd:c25:c25:94de:3093/1282c19:dd:d9:dd:c25:c25:94de:3093
1492c19:dd:d9:dd:c25:c25:94de:3094/1282c19:dd:d9:dd:c25:c25:94de:3094
1502c19:dd:d9:dd:c25:c25:94de:3095/1282c19:dd:d9:dd:c25:c25:94de:3095
1512c19:dd:d9:dd:c25:c25:94de:3096/1282c19:dd:d9:dd:c25:c25:94de:3096
1522c19:dd:d9:dd:c25:c25:94de:3097/1282c19:dd:d9:dd:c25:c25:94de:3097
1532c19:dd:d9:dd:c25:c25:94de:3098/1282c19:dd:d9:dd:c25:c25:94de:3098
1542c19:dd:d9:dd:c25:c25:94de:3099/1282c19:dd:d9:dd:c25:c25:94de:3099
1552c19:dd:d9:dd:c25:c25:94de:309a/1282c19:dd:d9:dd:c25:c25:94de:309a
1562c19:dd:d9:dd:c25:c25:94de:309b/1282c19:dd:d9:dd:c25:c25:94de:309b
1572c19:dd:d9:dd:c25:c25:94de:309c/1282c19:dd:d9:dd:c25:c25:94de:309c
1582c19:dd:d9:dd:c25:c25:94de:309d/1282c19:dd:d9:dd:c25:c25:94de:309d
1592c19:dd:d9:dd:c25:c25:94de:309e/1282c19:dd:d9:dd:c25:c25:94de:309e
1602c19:dd:d9:dd:c25:c25:94de:309f/1282c19:dd:d9:dd:c25:c25:94de:309f
1612c19:dd:d9:dd:c25:c25:94de:30a0/1282c19:dd:d9:dd:c25:c25:94de:30a0
1622c19:dd:d9:dd:c25:c25:94de:30a1/1282c19:dd:d9:dd:c25:c25:94de:30a1
1632c19:dd:d9:dd:c25:c25:94de:30a2/1282c19:dd:d9:dd:c25:c25:94de:30a2
1642c19:dd:d9:dd:c25:c25:94de:30a3/1282c19:dd:d9:dd:c25:c25:94de:30a3
1652c19:dd:d9:dd:c25:c25:94de:30a4/1282c19:dd:d9:dd:c25:c25:94de:30a4
1662c19:dd:d9:dd:c25:c25:94de:30a5/1282c19:dd:d9:dd:c25:c25:94de:30a5
1672c19:dd:d9:dd:c25:c25:94de:30a6/1282c19:dd:d9:dd:c25:c25:94de:30a6
1682c19:dd:d9:dd:c25:c25:94de:30a7/1282c19:dd:d9:dd:c25:c25:94de:30a7
1692c19:dd:d9:dd:c25:c25:94de:30a8/1282c19:dd:d9:dd:c25:c25:94de:30a8
1702c19:dd:d9:dd:c25:c25:94de:30a9/1282c19:dd:d9:dd:c25:c25:94de:30a9
1712c19:dd:d9:dd:c25:c25:94de:30aa/1282c19:dd:d9:dd:c25:c25:94de:30aa
1722c19:dd:d9:dd:c25:c25:94de:30ab/1282c19:dd:d9:dd:c25:c25:94de:30ab
1732c19:dd:d9:dd:c25:c25:94de:30ac/1282c19:dd:d9:dd:c25:c25:94de:30ac
1742c19:dd:d9:dd:c25:c25:94de:30ad/1282c19:dd:d9:dd:c25:c25:94de:30ad
1752c19:dd:d9:dd:c25:c25:94de:30ae/1282c19:dd:d9:dd:c25:c25:94de:30ae
1762c19:dd:d9:dd:c25:c25:94de:30af/1282c19:dd:d9:dd:c25:c25:94de:30af
1772c19:dd:d9:dd:c25:c25:94de:30b0/1282c19:dd:d9:dd:c25:c25:94de:30b0
1782c19:dd:d9:dd:c25:c25:94de:30b1/1282c19:dd:d9:dd:c25:c25:94de:30b1
1792c19:dd:d9:dd:c25:c25:94de:30b2/1282c19:dd:d9:dd:c25:c25:94de:30b2
1802c19:dd:d9:dd:c25:c25:94de:30b3/1282c19:dd:d9:dd:c25:c25:94de:30b3
1812c19:dd:d9:dd:c25:c25:94de:30b4/1282c19:dd:d9:dd:c25:c25:94de:30b4
1822c19:dd:d9:dd:c25:c25:94de:30b5/1282c19:dd:d9:dd:c25:c25:94de:30b5
1832c19:dd:d9:dd:c25:c25:94de:30b6/1282c19:dd:d9:dd:c25:c25:94de:30b6
1842c19:dd:d9:dd:c25:c25:94de:30b7/1282c19:dd:d9:dd:c25:c25:94de:30b7
1852c19:dd:d9:dd:c25:c25:94de:30b8/1282c19:dd:d9:dd:c25:c25:94de:30b8
1862c19:dd:d9:dd:c25:c25:94de:30b9/1282c19:dd:d9:dd:c25:c25:94de:30b9
1872c19:dd:d9:dd:c25:c25:94de:30ba/1282c19:dd:d9:dd:c25:c25:94de:30ba
1882c19:dd:d9:dd:c25:c25:94de:30bb/1282c19:dd:d9:dd:c25:c25:94de:30bb
1892c19:dd:d9:dd:c25:c25:94de:30bc/1282c19:dd:d9:dd:c25:c25:94de:30bc
1902c19:dd:d9:dd:c25:c25:94de:30bd/1282c19:dd:d9:dd:c25:c25:94de:30bd
1912c19:dd:d9:dd:c25:c25:94de:30be/1282c19:dd:d9:dd:c25:c25:94de:30be
1922c19:dd:d9:dd:c25:c25:94de:30bf/1282c19:dd:d9:dd:c25:c25:94de:30bf
1932c19:dd:d9:dd:c25:c25:94de:30c0/1282c19:dd:d9:dd:c25:c25:94de:30c0
1942c19:dd:d9:dd:c25:c25:94de:30c1/1282c19:dd:d9:dd:c25:c25:94de:30c1
1952c19:dd:d9:dd:c25:c25:94de:30c2/1282c19:dd:d9:dd:c25:c25:94de:30c2
1962c19:dd:d9:dd:c25:c25:94de:30c3/1282c19:dd:d9:dd:c25:c25:94de:30c3
1972c19:dd:d9:dd:c25:c25:94de:30c4/1282c19:dd:d9:dd:c25:c25:94de:30c4
1982c19:dd:d9:dd:c25:c25:94de:30c5/1282c19:dd:d9:dd:c25:c25:94de:30c5
1992c19:dd:d9:dd:c25:c25:94de:30c6/1282c19:dd:d9:dd:c25:c25:94de:30c6
2002c19:dd:d9:dd:c25:c25:94de:30c7/1282c19:dd:d9:dd:c25:c25:94de:30c7
2012c19:dd:d9:dd:c25:c25:94de:30c8/1282c19:dd:d9:dd:c25:c25:94de:30c8
2022c19:dd:d9:dd:c25:c25:94de:30c9/1282c19:dd:d9:dd:c25:c25:94de:30c9
2032c19:dd:d9:dd:c25:c25:94de:30ca/1282c19:dd:d9:dd:c25:c25:94de:30ca
2042c19:dd:d9:dd:c25:c25:94de:30cb/1282c19:dd:d9:dd:c25:c25:94de:30cb
2052c19:dd:d9:dd:c25:c25:94de:30cc/1282c19:dd:d9:dd:c25:c25:94de:30cc
2062c19:dd:d9:dd:c25:c25:94de:30cd/1282c19:dd:d9:dd:c25:c25:94de:30cd
2072c19:dd:d9:dd:c25:c25:94de:30ce/1282c19:dd:d9:dd:c25:c25:94de:30ce
2082c19:dd:d9:dd:c25:c25:94de:30cf/1282c19:dd:d9:dd:c25:c25:94de:30cf
2092c19:dd:d9:dd:c25:c25:94de:30d0/1282c19:dd:d9:dd:c25:c25:94de:30d0
2102c19:dd:d9:dd:c25:c25:94de:30d1/1282c19:dd:d9:dd:c25:c25:94de:30d1
2112c19:dd:d9:dd:c25:c25:94de:30d2/1282c19:dd:d9:dd:c25:c25:94de:30d2
2122c19:dd:d9:dd:c25:c25:94de:30d3/1282c19:dd:d9:dd:c25:c25:94de:30d3
2132c19:dd:d9:dd:c25:c25:94de:30d4/1282c19:dd:d9:dd:c25:c25:94de:30d4
2142c19:dd:d9:dd:c25:c25:94de:30d5/1282c19:dd:d9:dd:c25:c25:94de:30d5
2152c19:dd:d9:dd:c25:c25:94de:30d6/1282c19:dd:d9:dd:c25:c25:94de:30d6
2162c19:dd:d9:dd:c25:c25:94de:30d7/1282c19:dd:d9:dd:c25:c25:94de:30d7
2172c19:dd:d9:dd:c25:c25:94de:30d8/1282c19:dd:d9:dd:c25:c25:94de:30d8
2182c19:dd:d9:dd:c25:c25:94de:30d9/1282c19:dd:d9:dd:c25:c25:94de:30d9
2192c19:dd:d9:dd:c25:c25:94de:30da/1282c19:dd:d9:dd:c25:c25:94de:30da
2202c19:dd:d9:dd:c25:c25:94de:30db/1282c19:dd:d9:dd:c25:c25:94de:30db
2212c19:dd:d9:dd:c25:c25:94de:30dc/1282c19:dd:d9:dd:c25:c25:94de:30dc
2222c19:dd:d9:dd:c25:c25:94de:30dd/1282c19:dd:d9:dd:c25:c25:94de:30dd
2232c19:dd:d9:dd:c25:c25:94de:30de/1282c19:dd:d9:dd:c25:c25:94de:30de
2242c19:dd:d9:dd:c25:c25:94de:30df/1282c19:dd:d9:dd:c25:c25:94de:30df
2252c19:dd:d9:dd:c25:c25:94de:30e0/1282c19:dd:d9:dd:c25:c25:94de:30e0
2262c19:dd:d9:dd:c25:c25:94de:30e1/1282c19:dd:d9:dd:c25:c25:94de:30e1
2272c19:dd:d9:dd:c25:c25:94de:30e2/1282c19:dd:d9:dd:c25:c25:94de:30e2
2282c19:dd:d9:dd:c25:c25:94de:30e3/1282c19:dd:d9:dd:c25:c25:94de:30e3
2292c19:dd:d9:dd:c25:c25:94de:30e4/1282c19:dd:d9:dd:c25:c25:94de:30e4
2302c19:dd:d9:dd:c25:c25:94de:30e5/1282c19:dd:d9:dd:c25:c25:94de:30e5
2312c19:dd:d9:dd:c25:c25:94de:30e6/1282c19:dd:d9:dd:c25:c25:94de:30e6
2322c19:dd:d9:dd:c25:c25:94de:30e7/1282c19:dd:d9:dd:c25:c25:94de:30e7
2332c19:dd:d9:dd:c25:c25:94de:30e8/1282c19:dd:d9:dd:c25:c25:94de:30e8
2342c19:dd:d9:dd:c25:c25:94de:30e9/1282c19:dd:d9:dd:c25:c25:94de:30e9
2352c19:dd:d9:dd:c25:c25:94de:30ea/1282c19:dd:d9:dd:c25:c25:94de:30ea
2362c19:dd:d9:dd:c25:c25:94de:30eb/1282c19:dd:d9:dd:c25:c25:94de:30eb
2372c19:dd:d9:dd:c25:c25:94de:30ec/1282c19:dd:d9:dd:c25:c25:94de:30ec
2382c19:dd:d9:dd:c25:c25:94de:30ed/1282c19:dd:d9:dd:c25:c25:94de:30ed
2392c19:dd:d9:dd:c25:c25:94de:30ee/1282c19:dd:d9:dd:c25:c25:94de:30ee
2402c19:dd:d9:dd:c25:c25:94de:30ef/1282c19:dd:d9:dd:c25:c25:94de:30ef
2412c19:dd:d9:dd:c25:c25:94de:30f0/1282c19:dd:d9:dd:c25:c25:94de:30f0
2422c19:dd:d9:dd:c25:c25:94de:30f1/1282c19:dd:d9:dd:c25:c25:94de:30f1
2432c19:dd:d9:dd:c25:c25:94de:30f2/1282c19:dd:d9:dd:c25:c25:94de:30f2
2442c19:dd:d9:dd:c25:c25:94de:30f3/1282c19:dd:d9:dd:c25:c25:94de:30f3
2452c19:dd:d9:dd:c25:c25:94de:30f4/1282c19:dd:d9:dd:c25:c25:94de:30f4
2462c19:dd:d9:dd:c25:c25:94de:30f5/1282c19:dd:d9:dd:c25:c25:94de:30f5
2472c19:dd:d9:dd:c25:c25:94de:30f6/1282c19:dd:d9:dd:c25:c25:94de:30f6
2482c19:dd:d9:dd:c25:c25:94de:30f7/1282c19:dd:d9:dd:c25:c25:94de:30f7
2492c19:dd:d9:dd:c25:c25:94de:30f8/1282c19:dd:d9:dd:c25:c25:94de:30f8
2502c19:dd:d9:dd:c25:c25:94de:30f9/1282c19:dd:d9:dd:c25:c25:94de:30f9
2512c19:dd:d9:dd:c25:c25:94de:30fa/1282c19:dd:d9:dd:c25:c25:94de:30fa
2522c19:dd:d9:dd:c25:c25:94de:30fb/1282c19:dd:d9:dd:c25:c25:94de:30fb
2532c19:dd:d9:dd:c25:c25:94de:30fc/1282c19:dd:d9:dd:c25:c25:94de:30fc
2542c19:dd:d9:dd:c25:c25:94de:30fd/1282c19:dd:d9:dd:c25:c25:94de:30fd
2552c19:dd:d9:dd:c25:c25:94de:30fe/1282c19:dd:d9:dd:c25:c25:94de:30fe
2562c19:dd:d9:dd:c25:c25:94de:30ff/1282c19:dd:d9:dd:c25:c25:94de:30ff

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.