The database of User:RonaldB now (Feb. 2011) contains some 60k URLs of so called web proxies, of which some 52k have ever been confirmed (via automatic scanning) to be real ones. Most web proxies utilize so called shared hosting, implying that multiple URLs share the same IP address.

When re-running such scans, it has been noted that these shared IP addresses are not static and may change for various reasons, most likely a re-arrangement of IPs by the web hosting provider and more recently by the advent of cloud computing as offered by increasingly more providers, making the IP assignment more or less dynamic.

To cope with this, a project has been started (end of 2010) to replace the preemptive blocking of individual IP addresses, as used by these web proxies, by range blocks. This list provides an overview of such ranges.

The columns denote the following:

IP range

self-explanatory

IPmax

just for convenience for people not so familiar with CIDR notation

Block date

date of the initial preemptive block on nl:wp

IPcount

the number of individual IPs that have ever been in use by web proxies

URLcount

the number of URLs that have ever been hosted within the range

Hosting provider

the URL of the hosting provider. Please note that sometimes one need to precede this url by www., in order to get a response.

IP blocks

remaining individual IP blocks on nl:wp. Regularly such individual IP blocks will be replaced by just the parent range block.

The ranges as specified are sometimes parent ranges, sometimes child ranges. The normal WHOIS tools (as e.g. domaintools) usually provide information on the smallest range encompassing an individual IP address. However a WHOIS via the authoritative RIRs (such as RIPE or ARIN), provides better possibilities to find parent ranges (in case the provider seems to be just a reseller) or child ranges (in case the standard response contains a mixture of IP sub-ranges).

There are more ranges, exclusively used for web hosting, blocked on nl:wp. These are not listed here, but will be added as soon as web proxy URLs can be assigned to these. The same will obviously happen with new ranges. Estimated frequency for significant changes is something like a month.