nanog mailing list archives

Re: Partial Use Of one Regions IP Block in another


From: Owen DeLong <owen () delong com>
Date: Thu, 20 May 2010 09:36:02 -0700


On May 20, 2010, at 9:14 AM, George Bonser wrote:



-----Original Message-----
From: Owen DeLong [mailto:owen () delong com]
Sent: Thursday, May 20, 2010 7:37 AM
To: Net
Cc: nanog () nanog org
Subject: Re: Partial Use Of one Regions IP Block in another


You state "Obv, the best approach...". I don't think so. I think the
best
approach is whatever allows you to make most efficient use of your
address space. Usually this will be from a single RIR rather than a
multiple RIR approach.

Owen

The one drawback to that would be people who attempt to do geographical
based service provisioning. Say a company based in the US uses part of
their block in Europe or APAC.  When they do a DNS request for a service
address from $GLOBAL_CONTENT_PROVIDER, they end up getting the US
service address because the content provider believes the request is
coming from the US resulting in poor performance.  In other words, if a
service relies on connection to other services that try to do
geographical affinity, it could lead to a sub-optimal experience.

I have ZERO sympathy for people who attempt to do this getting wrong
answers.  There is little correlation between geography and IP addresses.

In fact, I know lots of people who consider it a benefit to have ARIN addresses
in other parts of the world because it allows them to get to content that isn't
allowed to APNIC addresses on the belief that this somehow protects
copyright or other issues for content distribution. I find that pretty amusing.

It could also cause problems where the content is different (or possibly
prohibited) depending on the geographical location of the requestor
which some folks try to determine by source address (but which is
actually quite idiotic, in my opinion, because as you see from this
thread, an IP address in no way relates to where the person really is,
it only relates to where the entity to whom it was issued is located).

Again, ZERO sympathy here.  Especially where someone is trying to
use source IP as a mechansim for determining who they are willing
to distribute their content to. 

Been there and experienced issues like that before.  It can even be bad
when you are given an IP block that might have been used before by
someone in another region.

Can be bad when given an IP block that might have been used before
by someone in the same region.  That's not particularly different.

Can be bad if you get space from one of the more recent /8s that has
lots of cruft from having been used as pseudo-RFC-1918 space, too.

We're scraping the bottom of the barrel for IPv4 space these days.
It is what it is, and it's only going to get worse in IPv4.  Time to go
to IPv6.

Owen



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