IP header option
OK another dumb question,
in CEF packets with the IP header option can't be "switched" and are punted to the router process.
but exactly what is the header option? I thoughts it was to do with things like ICMP. But Now I am thinking that is completely wrong, would things like source routing be contained in options?
Any one care to fill in the knowledge gap for me please ?
Cheers
in CEF packets with the IP header option can't be "switched" and are punted to the router process.
but exactly what is the header option? I thoughts it was to do with things like ICMP. But Now I am thinking that is completely wrong, would things like source routing be contained in options?
Any one care to fill in the knowledge gap for me please ?
Cheers
- If you can't explain it simply, you don't understand it well enough. Albert Einstein
- An arrow can only be shot by pulling it backward. So when life is dragging you back with difficulties. It means that its going to launch you into something great. So just focus and keep aiming.
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Comments
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Met44
Member Posts: 194
Any packets using the "options" field in the IP header are off limits for CEF, so this includes things like source routing, route recording, and the timestamp request option. Note that the router must do extra "stuff" with any of these options (if such processing was not disabled) -- that's why the packet gets punted up to the more intelligent methods of dealing with packets. You could lab this out using extended ping commands to populate the IP header options and the show commands to view cef punts if it would help. -
DevilWAH
Member Posts: 2,997 ■■■■■■■■□□
Any packets using the "options" field in the IP header are off limits for CEF, so this includes things like source routing, route recording, and the timestamp request option. Note that the router must do extra "stuff" with any of these options (if such processing was not disabled) -- that's why the packet gets punted up to the more intelligent methods of dealing with packets. You could lab this out using extended ping commands to populate the IP header options and the show commands to view cef punts if it would help.
No that's cool I get the CEF processes and punting frames. I was just curious what IP/Routing features use the IP header options. I was wondering if there is a complete list of them anywhere.- If you can't explain it simply, you don't understand it well enough. Albert Einstein
- An arrow can only be shot by pulling it backward. So when life is dragging you back with difficulties. It means that its going to launch you into something great. So just focus and keep aiming.
Linkin Profile - Blog: http://Devilwah.com