Fastnetmon Advertise /24 Subnet
Posted: Fri Jan 29, 2021 12:21 pm
Hello. I'm testing Fastnetmon to advertise /24 subnet to scrubbing center. Here is the topology : https://prnt.sc/xsytvw
I've successfully setup BGP filter for RTBH to ISP using Fastnetmon (advertise /32). Next I applied the same routing filter (but with different bgp community) to advertise /24 subnet to scrubbing center, but it doesn't work.
Suppose my AS is 456, and the scrubbing AS is 789. BGP Community for RTBH is 666, for scrubbing is 999.
GoBGP will send prefix with community 456:999 to my edge router. Here is the In-Filter of my edge router to receive the advertisement from GoBGP :
Then I need to forward the advertisement from GoBGP to scrubbing center. This setup works with /32 prefix. Here is the Out-Filter to advertise prefix from edge router to scrubbing center :
I can see the prefix is delivered from GoBGP, here is from routing table :
But I can't forward the advertisement (/24) from GoBGP to my scrubbing center. How can I get this to work so I can automatically advertise /24 to scrubbing center?
Thank you.
I've successfully setup BGP filter for RTBH to ISP using Fastnetmon (advertise /32). Next I applied the same routing filter (but with different bgp community) to advertise /24 subnet to scrubbing center, but it doesn't work.
Suppose my AS is 456, and the scrubbing AS is 789. BGP Community for RTBH is 666, for scrubbing is 999.
GoBGP will send prefix with community 456:999 to my edge router. Here is the In-Filter of my edge router to receive the advertisement from GoBGP :
Code: Select all
Flags: X - disabled
0 ;;; Community 666 - Blackhole ISP
chain=FROM-SENSOR bgp-communities=456:666 invert-match=no
action=accept set-bgp-local-pref=200 set-bgp-prepend-path=""
set-bgp-communities=456:666
1 ;;; Community 999 - Scrubbing
chain=FROM-SENSOR bgp-communities=456:999 invert-match=no
action=accept set-bgp-local-pref=200 set-bgp-prepend-path=""
set-bgp-communities=456:999
2 chain=FROM-SENSOR bgp-communities=456:999 invert-match=no
action=discard set-bgp-prepend-path=""Then I need to forward the advertisement from GoBGP to scrubbing center. This setup works with /32 prefix. Here is the Out-Filter to advertise prefix from edge router to scrubbing center :
Code: Select all
Flags: X - disabled
0 chain=TO-SCRUBBING bgp-communities=456:999 invert-match=no action=passthrough
set-bgp-prepend-path=""
1 chain=TO-SCRUBBING bgp-communities=456:999 invert-match=no action=accept
set-bgp-prepend-path="" set-bgp-communities=""
2 chain=TO-SCRUBBING invert-match=no action=discard set-bgp-prepend-path=""I can see the prefix is delivered from GoBGP, here is from routing table :
Code: Select all
Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit
0 ADC dst-address=10.10.30.0/24 pref-src=10.10.30.1 gateway=ether2-GW
gateway-status=ether2-GW reachable distance=0 scope=10
1 Db dst-address=10.10.30.0/24 gateway=10.10.30.253
gateway-status=10.10.30.253 reachable via ether2-GW distance=200
scope=40 target-scope=30 bgp-local-pref=200 bgp-origin=igp
bgp-communities=55688:999 received-from=TEST-ROUTERBut I can't forward the advertisement (/24) from GoBGP to my scrubbing center. How can I get this to work so I can automatically advertise /24 to scrubbing center?
Thank you.