Address Assignment Question

Jon Lewis jlewis at lewis.org
Mon Jun 20 09:10:10 CDT 2011


On Mon, 20 Jun 2011, Steve Richardson wrote:

> We have a customer who, over the years, has amassed several small subnet
> assignments from us for their colo.  They are an email marketer.  They have
> requested these assignments in as many discontiguous netblocks as we can
> manage.  They are now asking for more addresses (a /24s worth) in even more
> discontiguous blocks.  What I'd like to know is whether there is a
> legitimate use for so many addresses in discontiguous networks besides
> spam?

The most common uses for such IP assignments are SEO and snowshoe 
spamming.  It may seem a crazy idea, but have you asked them why they need 
a bunch of subnets from as many different /24s as possible rather than 
just a /24?  What was their justification for the /24 (regardless of 
contiguity)?

> IPv4 addresses are becoming more of a scarce resource.  However, if they
> *are* legitimate, which certainly is possible, are discontiguous networks a
> common practice for even legit operators, as it's quite likely that even
> legit email marketers will end up being blocked because someone accidentally
> hit 'Spam' instead of 'Delete' in their AOL software?

No...and I'd say asking for that is a gamble which suggests they're not 
legit.  A legit mailer should have no objection (or even prefer) to have 
all their IPs contiguous, so as not to be mixed up with and confused for 
another customer (one that might be a worse spammer than they are).

----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
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