IPv4 Addresses

Overview

The 32-bit address space used on the IPv4 Internet has been almost completely exhausted. As a result, it has not been possible for Personal Telco to obtain more than a handful of global-scope IPv4 addresses at a time.

Since we are unable to use global-scope IPv4 address space on our public networks, we are forced to use private IPv4 address space (as defined in RFC 1918) along with cone NAT to provide limited IPv4 Internet connectivity.

We use only subnets within the 10.11/16 range; this page is the authoritative list of these allocations. If you are involved in the operation of a public network in the Portland metropolitan area, you are welcome to use this address space as well. See the Guidelines section below for details.

Note that IPv6 does not suffer from such a shortage of address space or any of the related issues; global-scope IPv6 addresses and subnets are easily obtained. See IPv6 for more information.

History

Many years ago, FreeNetworks set up a wiki page which was intended to coordinate the usage of private address space among community networks. Each organization could list the blocks they were using. The idea was that eventually some of these networks might somehow be connected together to form a larger network; by using the registry, they could reasonably expect that inter-community address conflicts would be virtually eliminated.

Almost immediately after they set this page up, we participated by listing our usage of the 10.11/16 block. Years later, it is no longer clear whether we started using this block before or after listing it in the registry; if anyone is able to clarify this point, please do.

The FreeNetworks wiki page which held the registry was named "NetworkAddressAllocations"; this page is named after it. Sadly, that wiki seems to have completely disappeared, and along with it went our best chance at establishing IPv4 connectivity with other distant community networks. Nevertheless, we are still using 10.11/16 and will likely continue doing so indefinitely.

Guidelines

If you are using (or planning to use) a subnet in the 10.11/16 block, and are interested in avoiding conflicts with other networks, you should document your allocation by adding it to the list in the Subnets section below.

Please do your best to avoid conflicting or overlapping allocations, and try to keep the list in numeric order by subnet. If in doubt, just ask around on the MailingLists, IRC or whatever you prefer.

We also ask that you use the smallest possible subnet that will meet your needs; the following table is provided to help you make that decision. You can make a selection based on either the recommendations given in the notes (the right column) or the number of addresses which will be available on your network (the left column). The bitmask and netmask in the center columns of the row you select should then be used in your configuration.

A web-based calculator tool is also available: http://www.subnet-calculator.com/cidr.php

Subnets

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