Meaning and significance of "scope" in FIB printouts?

[AlexFerenX]

Hi!

every KB I've seen, including 212757 & 199661, omits explanation of "scope" attribute in Kernel Table/FIB printout.

I understand it originate from Linux Kernel Table, but, in Fortigate context, can anyone may volunteer qualified meanings of 0, 253, 254 and 255, and significance of each?

Thanks!

[esalija]

Hi @AlexFerenX 

In the context of Kernel routing tables, the "scope" value indicates the reachability of a route.

- A "scope" value of 0 indicates a global route.

This means the route is valid for the entire network and can be used to route traffic beyond the local network segment.

- A "scope" value of 253 typically represents a site-local route.

- This means the route is intended for use within a specific site or organisation and is not meant to be used for routing traffic outside of that site.

- A scope value of 254 typically represents a link-local route.

This means the route is only valid within the local network segment and is not intended for routing traffic beyond the local link.

- A "scope" value of 255 typically represents a host route.

This means the route is specific to a single host or device, and it is used to direct traffic to that particular host.

Best regards,
Erlin

[AlexFerenX]

Hi @esalija,

thank you.

So we're on same page - is yours a Linux-generic or is it FortiOS-specific answer? 

I have to ask because "...  route is intended for use within a specific site or organisation ..." doesn't seem FortiOS-specific at all.

Alex

[esalija]

HI @AlexFerenX 

The explanation provided for scope values is more aligned with general networking concepts and Linux-based systems rather than being FortiOS-specific.

Best regards,

Erlin

[AlexFerenX]

Hi @esalija 

since this is a Fortinet/Fortgate/FortiOS support forum and not a Linux support forum, can you confirm that those values and explanations apply in this context?

Thanks, Alex

[esalija]

Hi @AlexFerenX ,

Yes, the values and explanation are general networking concepts.

Best regards,

Erlin

[AlexFerenX]

HI @esalija, 

so, no - you didn't answer the question because I wasn't requesting you Google and regurgitate Linux Kernel information - I was requesting Fortinet/Fortgate/FortiOS-specific answer, as per "Fortigate" label for this thread and "... in Fortigate context" in the original question.

If I wanted the former, I'd have asked in a different community forum.

Thanks!