[VoiceOps] International IP blacklist

Alex Balashov abalashov at evaristesys.com
Sun Apr 18 04:08:36 EDT 2010

On 04/18/2010 03:37 AM, anorexicpoodle wrote:

> Though this topic does raise a question I have been kicking around for a
> while, has anyone here tried implementing a SIP equivalent of URPF on
> your border controllers or proxies on the peering side, so if you cannot
> determine a route back to the calling number you drop the call to IVR or
> reject? Obviously implementing UPRF at L3 has saved me tons of headaches
> in other facets, but certainly a L5 solution could alleviate a potential
> ton of spam calls that come through normal PSTN connections. Thoughts?

This would seem to come down to the question of what exactly it means 
to have or not have a route to a given calling number.

Validate it against basic NANPA form rules?  Look it up prefix-wise 
against a current list of currently allocated NANPA and Pooling 
blocks, or against the LERG?  See if at least one of your termination 
carriers has a specific route of a certain minimum prefix length (i.e. 
longer than just "1")?

Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/

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