*** Resending note of 09/23/96 18:38 Subject: Re: SYN flood messages flooding my mailbox

Not. Every entry in the filter contains the following data:

[Prefix] [Prefix Length] [Bitmask]

where bitmask has a bit per every interfaces, so the bit if set if packet matching the prefix is allowed from that interface.

How do you handle the case of an inter-exchange point, with multiple BGP neighbors per interface? The MAE-East NAP is the worst case (and not everyone at a NAP is a "transit AS"). If you tried to handle the case of an IXP, wouldn't you have to filter based on both interface and MAC address?

Since in practically all cases all prefixes (NOT routes!) found in all RIBs are also found in FIB (exceptions are proxy aggregation and/or restricted end-to-end reacheability) the size of the list is the same as size of FIB.

What do you do with a prefix announced through two providers, where the prefix is taken from one provider's supernet? Wouldn't you need to check the RIB entries of all matching prefixes (including default)? -- Richard Woundy, IBM