[AusNOG] Whats peoples BCP for Unused IP Space on Routers ?

[Mark Smith]

----- Original Message -----
> From: Mark Newton <newton at atdot.dotat.org>
> To: Shaun Deans <shaun at kadeo.com.au>
> Cc: ausnog at lists.ausnog.net
> Sent: Monday, 3 December 2012 11:00 AM
> Subject: Re: [AusNOG] Whats peoples BCP for Unused IP Space on Routers ?
> 
> On Mon, Dec 03, 2012 at 10:55:23AM +1100, Shaun Deans wrote:
> 
>>  I'm looking for some quick feedback on what peoples BCP (Best Common
>>  Practice) is when it comes to unused ip space.
> 
> Null route with a high administrative distance.
> 

It's also worth disabling IP unreachables on the null0 interface as it causes the dropped packets to be dropped by CEF rather than punting them to the control plane for ICMP unreachable generation e.g.

(null0 is a hidden interface, it'll show up if you type in 'int null0')

int null0
no ip unreachables



"no ip unreachables" on the following:

http://www.bgpexpert.com/archive2003q4.php


And some Cisco.com text about it.

http://www.cisco.com/en/US/docs/routers/access/cisco_router_and_security_device_manager/25/software/user/guide/SAudt.html#wp1029695