Pitfalls of annoucing /24s

Wed Oct 15 21:16:26 UTC 2003

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:pr at isprime.com] 
Sent: Wednesday, October 15, 2003 1:47 PM
To: John Palmer
Cc: nanog at merit.edu
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" <jsmith at vitalstream.com>
> To: <nanog at merit.edu>
> 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.