nanog mailing list archives
Re: Blocking spoofing at the source (was: ICMP Attacks??)
From: Robert Sanders <rsanders () mindspring net>
Date: 29 Aug 1997 18:25:20 -0400
Phil Howard <phil () charon milepost com> writes:
As long as _one_ _of_ _the_ _routes_ would go back on the interface the packet arrived on, not necessarily the best route, then the logic would work in the majority of cases that I know of. But this could require a more extensive route lookup, which would do more than just double the CPU time looking up routes.
Not necessarily. For routers at the very edge of the network, each interface probably has a small and fairly static set of route candidates through it. The router could automatically update a magic IP traffic filter that's updated whenever the set of routes through the interface changes. This, possibly coupled with some aggressive aggregation, is for most cases a Simple Matter Of Programming that wouldn't significantly impact router performance. Even at the core, the cost of updating filter lists due to route flap has to be much, much less than the cost of doubling (or worse) the number of route table lookups per packet forwarded. regards, -- Robert
Current thread:
- Re: ICMP Attacks???????, (continued)
- Re: ICMP Attacks??????? Jon Green (Aug 22)
- Re: ICMP Attacks??????? Greg A. Woods (Aug 22)
- Re: ICMP Attacks??????? Joe Rhett (Aug 22)
- Message not available
- Re: ICMP Attacks??????? Jay R. Ashworth (Aug 22)
- Re: ICMP Attacks??????? Josh Beck (Aug 21)
- Blocking spoofing at the source (was: ICMP Attacks??) Joe Rhett (Aug 22)
- Re: Blocking spoofing at the source (was: ICMP Attacks??) Josh Beck (Aug 22)
- Message not available
- Re: Blocking spoofing at the source (was: ICMP Attacks??) Jay R. Ashworth (Aug 22)
- Re: Blocking spoofing at the source (was: ICMP Attacks??) Robert Sanders (Aug 29)
- Re: Blocking spoofing at the source (was: ICMP Attacks??) Phil Howard (Aug 22)
- Re: Blocking spoofing at the source (was: ICMP Attacks??) Robert Sanders (Aug 29)
- Re: ICMP Attacks??????? Peter E. Giza (Aug 21)
- Re: ICMP Attacks??????? Jon Lewis (Aug 21)
- Re: ICMP Attacks??????? Alex "Mr. Worf" Yuriev (Aug 21)
- Re: ICMP Attacks??????? Jon Lewis (Aug 21)
- Re: ICMP Attacks??????? Edward Henigin (Aug 21)
- Re: ICMP Attacks??????? Alex Przekupowski (Aug 22)
- Message not available
- Re: ICMP Attacks??????? Jay R. Ashworth (Aug 22)
- Message not available
- Re: ICMP Attacks??????? Jay R. Ashworth (Aug 26)