*** 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?
-- Richard Woundy, IBM
I'm starting to think that MAC-address-filtering ability would be a VERY useful addition for this sort of thing, esp. if it could be written as: access 200 deny ip any host 198.7.0.2 src-mac 0000.1111.2222 access 200 permit ip any any I think this isn't very possible given the IOS architecture; hopefully I'm wrong. Avi