Hi Jeoren, The idea is that for every router the packet goes through, we need to check the IP address of all the interface addresses, and make sure that the none of the interface address either before or after in the source routing header match any of the IP address of the packet.
Yes RPF check could be helpful too. But I am unsure how it would behave in case of ECMP other other anomaly cases. Thanks, Vishwas On 6/3/07, Jeroen Massar <[EMAIL PROTECTED]> wrote:
Vishwas Manral wrote: > Hi, > > We have posted a draft which checks for loops in the source routed > header. It works for nearly all the cases. The reason is in case a new > header is added to replace the RH0, or if the RH0 is not deprecated > (for reasons that it is required by the management) then we can as > well use the checks in the RH0 header itself. > > Such packets should however be rate limited and such checks will > probably best be performed by software. > > http://www.ietf.org/internet-drafts/draft-manral-ipv6-detecting-loops-rh-01.txt Properly configured uRPF already solves most of the routing loops. Section 3 very shortly describes a method of 'checking if the packet goes through a router twice', but it doesn't actually explain how it can be accomplished, it only explains that one can't because there is no 'routing identifier'. The second paragraph of section 3 in effect describes performing uRPF on the RH0 header. Also, if you would check for a loop, the typical "management" use of RH0 (read: traceroute6) stops working, as in most cases the packet will come back over the same path as it was sent. Greets, Jeroen
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