North American Network Operators Group

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RE: Pitfalls of annoucing /24s

  • From: william
  • Date: Wed Oct 15 17:34:49 2003

Don't know for certain, but I announce from time-time singular /24s out 
of my 64.x block (without announcing entire block, although at times 
I'd announce entire block as two /20s well) and have seen no problems with 
verio or anybody else.

On Wed, 15 Oct 2003, Jean-Christophe Smith wrote:

> 
> 
> I noticed the verio filter policy, in relation to inbound:
>  - In the traditional Class A space (i.e., 0/1), we accept /22 and shorter.
> 
> If I want to announce a /24 in the 64.x.x.x space(traditional Class A space)
> am I'm going to have a problem with other networks that have peer filters
> similar to Verios?
> 
> Thanks,
> Jean-Christophe Smith
> 
> -----Original Message-----
> From: Phil Rosenthal [mailto:[email protected]] 
> Sent: Wednesday, October 15, 2003 1:47 PM
> To: John Palmer
> Cc: [email protected]
> Subject: Re: Pitfalls of annoucing /24s
> 
> 
> http://info.us.bb.verio.net/routing.html#PeerFilter
> 
> That's how Verio does it, and I assume, that's how most people who 
> filter by length do it as well.
> 
> --Phil
> On Oct 15, 2003, at 4:40 PM, John Palmer wrote:
> 
> >
> > Good question.
> >
> > You know there are thousands of legacy /24's out there that were 
> > allocated by
> > IANA as /24's How can you aggregate them up if all you have is the /24?
> >
> > To those who filter out /24's - how is this done - just by the netmask 
> > size?
> >
> > ----- Original Message -----
> > From: "Jean-Christophe Smith" <[email protected]>
> > To: <[email protected]>
> > Sent: Wednesday, October 15, 2003 15:34
> > Subject: Pitfalls of annoucing /24s
> >
> >
> >>
> >>
> >> In current practice would there be serious jeopardy of portions of the
> >> internet not being able to reach this address space due to bgp 
> >> filters or
> >> other restrictions? What is the smallest acceptable block of IPs that 
> >> can be
> >> announced without adverse or unpredictable results? Verio would most 
> >> likely
> >> be picking up these routes from us. I don't want to cause a religious
> >> debate, but I am interested in what the industry consensus is.
> >>
> >> I'm just doing some research, any comments would be appreciated.
> >>
> >> Thanks,
> >> Jean-Christophe Smith
> >>
> >>
> >
> >
> --Phil Rosenthal
> ISPrime, Inc.