-------- Original Message -------- Subject: Re: The assignment of numerical addresses for Domain Names ?? From: William Case <billlinux@xxxxxxxxxx> To: For users of Fedora <fedora-list@xxxxxxxxxx> Date: Thursday, August 07, 2008 9:48:15 PM Hi Patrick; On Thu, 2008-08-07 at 21:54 -0430, Patrick O'Callaghan wrote:On Thu, 2008-08-07 at 21:20 -0400, William Case wrote:[snip]Some policy is documented at http://www.arin.net/policy/nrpm.html for example, but in general you can't look at a random IP number and tell what it stands for without further investigation. Use "whois" to find out about specific assigned numbers.Yes, I gather the assignments, given history and everything else, are too random to make them meaningful in themselves. But thanks for the policy URL above. I had looked at the ARIN site but hadn't gone through the policy page. There is no answer to my immediate question, but several incidental questions that I had put aside are answered there. IANA assigns /8's to regional authorities (such as ARIN). Each authority then has their own policy regarding assignments. From my experience, ARIN seems to simply uses the next available space out of their assignments. So if 10 companies requested IP blocks tomorrow, they would likely all receive IPs in the same /8. So basically, "first come, first serve" there is no order other than perhaps a bit of chronology if you know when a /8 started to be used. ARIN probably has more IPs than any other regional authority, so they tend to be more liberal with their assignments (they give out larger blocks). Typically they give out enough IPs to last a requesting organization a year or two of expansion. This keeps the number of routes down which lessens BGP routing overhead (RAM and CPU usage). Other authorities are more stingy. If you already have a block of IPs from ARIN and request one a year or two later, more than likely you'll get a block from a different /8. I'm sure ARIN audits IP usage occasionally, and probably tries to reclaim unused IP space, but they aren't very aggressive at it, and I'm sure a large portion of the IPs they've assigned go unused. --Blake |
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