FastNetMon /32 Blackhole Issue with Gateway IP

[vahidajorloo]

Hi Pavel,

I am facing an issue with FastNetMon and /32 blackhole announcements. Assume we have two IP addresses:

192.168.1.1 on the interface VLAN (SVI) as the gateway.
192.168.1.2 on the server in the same VLAN.

When I run the following command:
/usr/bin/fastnetmon_api_client ban 192.168.1.2 (the server ip)

It works as expected, and everything is fine.

However, when I run:

/usr/bin/fastnetmon_api_client ban 192.168.1.1 (the gateway IP, directly connected to the router)

nothing happens, and the IP is still reachable, even though I can see it in the BGP advertised table to the upstream peer.

Is there anything I can do to fix this issue?

[pavel-odintsov]

Hello!

Thank you for report.

I do not think that it related with FastNetMon as it's more about routing policy.

[pavel-odintsov]

Can you see that BGP announces are correctly created in both cases? If so then it's clearly BGP policy specific issue