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FLOWSPEC IN CISCO NCS5500 https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2019/pdf/BRKSPG-3012.pdf
show bgp ipv4 flowspec summary ! To see the current flowspec established sessions ! show flowspec afi-all detail ! To see what flowspec rules are currently applied AFI: IPv4 Flow :Dest:25.1.102.1/32,Proto:=17,Length:>=500&<=1550 Actions :Nexthop: 25.3.9.3 (bgp.1) Statistics (packets/bytes) Matched : 0/0 Dropped : 0/0 ! show policy-map transient type pbr pmap-name __bgpfs_default_IPv4 policy-map type pbr __bgpfs_default_IPv4 handle:0x36000002 table description: L3 IPv4 and IPv6 class handle:0x7600000a sequence 1024 match source-port 80 police rate 314152 bps conform-action transmit exceed-action drop
Vanilla configuration CSR1000v
router bgp 65000 bgp router-id 10.10.10.1 bgp log-neighbor-changes neighbor 10.10.11.143 remote-as 65000 ! ! address-family ipv4 flowspec neighbor 10.100.11.143 activate neighbor 10.100.11.143 send-community both exit-address-family !
FLOWSPEC NOTES RFC 5575
To filter (apply actions) on flows instead of penalising whole prefix ranges.
Actions to be done are transmitted via a BGP session from the controller (tells the router what to filter).SAFI 133.
More specifically, actions are encoded in EXT-COMMUNITIES
- We use exabgp to send and receive flowspec messages over the bgp connection
- In this articlewe can see how we do : flowspec-bgp-msg > acl > iptable rules
- however it gives for granted that we know how to generate and send flowspec messages.
- the message was sent by sFlow-RT/exabgp. More info here
- flowspec and containerlab: External Link
Flowspec in junos:
> show route table inetflow.0 extensive inetflow.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden) 4.4.4.4,*,proto=17,srcport=53,len>=450&<=600/term:1 (1 entry, 1 announced) TSI: KRT in dfwd; Action(s): discard,count Page 0 idx 0, (group ArborSP type Internal) Type 1 val a3be258 (adv_entry) Advertised metrics: Nexthop: Self Localpref: 100 AS path: [65530] ? Communities: 65530:100 65530:134 no-export traffic-rate:0:0 Cluster ID: 192.168.252.12 Originator ID: 10.2.25.68 Advertise: 000006f7 Path 4.4.4.4,*,proto=17,srcport=53,len>=450&
EXABGP NOTES:
exabgp api accepts these commands which can be entered either via python swriting stdio (exabgp listents it) or directly via exabgpcli.
Ways to start exabgp:
sudo env exabgp.daemon.user=root exabgp-4.0.0/sbin/exabgp exabgp.conf sudo env exabgp.debug.configuration=1 exabgp.debug.pdb=1 exabgp.daemon.user=root exabgp-4.0.0/sbin/exabgp exabgp.conf exabgp ./exabgp.conf
Links:
Examples of flowspec messages. They follow Juniper style
'announce route 100.10.0.0/24 next-hop self',
'announce route 200.20.0.0/24 next-hop self',
'announce flow route { match { destination 172.16.0.0/24; } then { discard; } }',
DDOS protection with RTBH and flowspec:
External_Link
Anycast can also be used to prevent inter-regios ddos (Cloudflare):
