North American Network Operators Group
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Who is announcing bogons?

  • From: Henry Kilmer
  • Date: Wed Apr 30 18:20:58 2003 
[email protected] writes:
>> Why do we expect the same ISP engineers to be better at configuring
>> negative lists or keeping them up to date?
>> 
>> According to Craig Labovitz's study published at Microsoft
>> http://www.research.microsoft.com/research/pubs/view.aspx?msr_tr_id=MSR-TR-2000-74
>> 100% of the ISP's surveyed filter inbound customer route announcements.
>> 
>
>Ahhh, but that was not the correct question to ask (I have not read the
>study). It is not whether ISP's filter inbound customer route 
>announcements. It is how they filter them. If the customer goes and 
>says I am going to announce 4.0.0.0/8  and the ISP just blindly adds
>that to the filter, we have a problem, but the ISP did answer that
>question truthfully. They are filtering.

Many ISPs use AS path filters for customers with a large number of
announcements.  Some implement netblock filters that are not exact
matches.  Both of these are examples where the ISP would honestly say
they filter but holes exist.

-Hank