Ettiquette and rules regarding Hijacked ASN's or IP space?

Mon Jun 9 20:52:36 UTC 2003

Andy Dills wrote:

> 
> What sorts of 'unique' routing policies justify an ASN?
> 

ISP has a corporate customer that decides to multi-home. While ISP is 
not multi-homed themselves, they must have an ASN to speak BGP and pass 
routing information between their corporate customer and their provider.

So an ISP may not quite fit the bill. Imagine a holding company that 
oversees a bunch of companies with independant networks, yet they all 
meet up at the holding company's network. For ease of maintenance 
between the companies (let's say there's 10 of them), they run BGP with 
private ASNs and the holding company default routes to their provider. 
Company X decides that they have a more network sensitive application 
which requires extra redundancy. They bring up a circuit to another 
network, get an ASN (as they are multi-homed now). In order for this to 
work, the Holding company must run an ASN and speak bgp to it's provider 
(and confederates are our friend).

I'm sure there are weirder routing policies, and some may even qualify 
for an ASN and BGP without any section of the network or it's 
downstreams being multi-homed. In some cases, it may be convenience or 
security.

For example. In the above senario, what if some of the real IP addresses 
held by a few of the companies should only be routed between the 
companies and not out to the public Internet. In such a senario, one 
could say that packet filtering is adequate, although not routing the 
netblock to begin with would definately be more secure (and fall under a 
routing policy requiring BGP in a non-multi-homed senario). With the 
holding company running BGP to it's provider, which netblocks get routed 
to the public and which go to companies X, Y, and Z only is trival. The 
RiR's do not dictate what proper routing policy is. They manage the 
assignments. Obviously, if all the companies fit within a /22, there 
might be some complaints. If the companies had a /18+ of address space, 
there might be just cause to allow them to do BGP and thus have an ASN, 
even with a single peer.

-Jack