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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Network Operators and smurf
Usially the low-end traffic is symmetrical. The problem is that CEF code and other anty-frauding realisations are appearing for the high-end routers, white they are nessesary for the low-end routers and useless for the core routers. For cisco, we need this future for 4500/4700/3640/2511 ASAP, 720x slightly, and don't need it for 75xx at all. On Sat, 25 Apr 1998, Al Reuben wrote: > Date: Sat, 25 Apr 1998 12:30:50 -0400 (EDT) > From: Al Reuben <[email protected]> > To: [email protected] > Cc: [email protected], [email protected] > Subject: Re: Network Operators and smurf > > > > This should (naturally) be implemented where routing is symmetric > > and where a "reverse-path check" (looking up the source address in > > the routing table to find the "expected" incoming interface and > > checking whether the packet did indeed enter through that interface) > > The big question is, what do you do if most of your traffic _is_ > asymetrical? I mean, a more basic check could be, "Does the network that > this packet was sourced from exist *at all*?", or "Do I have a route back > to the source network through *any* interface?" > > That would cut down on a good amount of spoofing, like the idiots who > spoof from 1.1.1.1 etc. > > > Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 239-10-10, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
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