North American Network Operators Group

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Re: Pitfalls of annoucing /24s

  • From: Matt Levine
  • Date: Wed Oct 15 18:00:41 2003

On Oct 15, 2003, at 4:46 PM, Phil Rosenthal wrote:


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.
Also worth noting that Verio does a loose-rpf check on their borders, so there's a possibility your packets will be dropped to multihomed customers who *do* have your /24 (if your best-path back to them is via verio.)..


--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.



--
Matt Levine <[email protected]>
"The Trouble with doing anything right the first time is that nobody appreciates how difficult it was." -BIX