Size | Comment |
---|---|
/29 | starter pack |
/28 | usually enough |
/27 | default allocation |
/26 | usually enough |
/25 | still a lot of IPs! |
/24 | are you an organization? |
The current guideline is to allocate a /27 or smaller by default, keeping space for up to a /26 if possible. Don't allocate more than a /25 worth of addresses and please think before you allocate: If you are going to have 2-3 servers and two VPN-spaces, a /28 is enough to suit your needs. Same will go for most home-networks. This is not public internet, but our IPv4-space is valuable too! If you need a /24 or larger, please ask in the IRC chan or on the mailing list.
For example, if there is no /27 free, you can split up a /26 into two /27. If you are looking for a /27 but there are none showing in the Open Netblocks tool, instead pick one of the /26 and click Take it! When registering your inetnum, instead of writing 172.2x.xxx.0-172.2x.xxx.63 then you can write 172.2x.xxx.0-172.2x.xxx.31. This will get you a /27 and save our IP space for others.
To register for example 172.20.150.0/27, you need to fill in 172.20.150.0-172.20.150.31.
{ "prefixes": { "29": [ "172.20.187.160_29", "172.20.187.168_29", "172.20.191.160_29", "172.20.224.96_29", "172.21.69.48_29", "172.22.156.0_29", "172.22.156.16_29", "172.22.156.8_29", "172.23.167.128_29", "172.23.167.136_29", "172.23.167.144_29", "172.23.217.32_29", "172.23.217.40_29", "172.23.223.96_29", "172.23.241.0_29" ], "28": [ "172.20.132.96_28", "172.20.133.128_28", "172.20.167.192_28", "172.20.167.208_28", "172.20.2.192_28", "172.20.2.208_28", "172.21.69.32_28", "172.21.90.0_28", "172.21.90.16_28", "172.22.129.32_28", "172.22.148.240_28", "172.22.149.32_28", "172.23.120.192_28", "172.23.179.160_28", "172.23.216.64_28" ], "27": [ "172.20.167.224_27", "172.20.18.128_27", "172.20.187.128_27", "172.20.2.224_27", "172.20.229.64_27", "172.21.78.192_27", "172.22.127.64_27", "172.22.146.192_27", "172.22.180.128_27", "172.22.180.160_27", "172.23.179.128_27", "172.23.189.128_27", "172.23.189.160_27", "172.23.189.192_27", "172.23.189.224_27" ], "26": [ "172.20.133.64_26", "172.20.154.0_26", "172.20.229.0_26", "172.21.76.64_26", "172.22.155.128_26", "172.22.155.192_26", "172.23.120.128_26", "172.23.161.128_26", "172.23.166.0_26", "172.23.166.128_26", "172.23.166.64_26", "172.23.179.0_26", "172.23.179.64_26", "172.23.190.0_26", "172.23.216.0_26" ], "25": [ "172.20.161.0_25", "172.20.187.0_25", "172.20.31.128_25", "172.21.101.128_25", "172.21.76.128_25", "172.21.91.128_25", "172.22.160.128_25", "172.22.183.128_25", "172.23.206.0_25", "172.23.206.128_25", "172.23.217.128_25", "172.23.226.128_25", "172.23.72.128_25", "172.23.76.128_25", "172.23.84.128_25" ], "24": [ "172.20.226.0_24", "172.20.3.0_24", "172.21.126.0_24", "172.21.127.0_24", "172.21.92.0_24", "172.22.104.0_24", "172.22.151.0_24", "172.23.115.0_24", "172.23.133.0_24", "172.23.169.0_24", "172.23.188.0_24", "172.23.204.0_24", "172.23.213.0_24", "172.23.214.0_24", "172.23.65.0_24" ], "23": [ "172.20.144.0_23", "172.20.60.0_23", "172.21.102.0_23", "172.21.124.0_23", "172.22.190.0_23", "172.23.134.0_23", "172.23.138.0_23", "172.23.154.0_23", "172.23.164.0_23", "172.23.184.0_23", "172.23.210.0_23", "172.23.218.0_23", "172.23.46.0_23", "172.23.80.0_23" ] }, "mtime": "2025-05-18T10:10:16Z" }