topic Re: BGP flowspec exclude interface in Data Center (SLX)

BGP flowspec exclude interface

MK24 — Wed, 12 Feb 2025 06:19:56 GMT

Hello,

Could you provide information on how to exclude Flowspec on an interface in SLX-OS 20.6.1 (SLX9740-40C) for returning traffic from the scrubber to prevent looping?

We don't see such an option in the interface options, and our route-map configurations do not seem to have any effect on this.

Re: BGP flowspec exclude interface

robert154 — Wed, 12 Feb 2025 08:58:40 GMT

@MK24 wrote:
Hello,
Could you provide information on how to exclude Flowspec on an interface in SLX-OS 20.6.1 (SLX9740-40C) for returning traffic from the scrubber to prevent looping?
We don't see such an option in the interface options, and our route-map configurations do not seem to have any effect on this.

To prevent Flowspec looping on an interface connected to a scrubbing appliance in SLX-OS 20.6.1, use the command interface <interface-name> ipv4 flowspec disable. This disables Flowspec processing on the specified interface, preventing rules from being applied to returning traffic and avoiding routing loops.

Re: BGP flowspec exclude interface

MK24 — Wed, 12 Feb 2025 09:42:48 GMT

Thank you for your help and response.
I would really like such a command to exist, but I don’t see it available anywhere on our side. The manual also does not mention it.
At which level should I execute it?

I get a syntax error with the command:
(config)# interface Ethernet 0/29 ipv4 flowspec disable
stating "unknown argument". for ipv4/ip

When I try:
(conf-if-eth-0/29)# ipv4 flowspec disable
I get "% Invalid input detected at '^' marker".

However, when entering:
(conf-if-eth-0/29)# ip flowspec disable
I get a syntax error with "unknown argument" for disable

This suggests that "ip flowspec," even though not visible, is being processed but with an incorrect argument.

Re: BGP flowspec exclude interface

MK24 — Thu, 13 Feb 2025 13:14:24 GMT

Sorry for pinging the topic, but this functionality/option is critical for us in relation to flowspec.
I would be very grateful for any help and guidance.

Re: BGP flowspec exclude interface

JoergKo — Mon, 05 Jan 2026 13:16:24 GMT

That command from robert154 before is LLM-spam. Currently it seems not possible to exclude the interface.