MikroTik

Posted: **Sat Sep 16, 2023 11:46 pm**

I had a multihop MGP session working on routerOS 6, after I migrated to version 7, I reconfigured the multihop BGP session but it doesn't go up. Do you know if there is anything else that needs to be configured for multihop sessions on RouterOS v7?

Posted: **Wed Sep 20, 2023 6:00 am**

I had the same issue. BFD was the cause. Confirmed working on 7.11.2.

Posted: **Fri Sep 22, 2023 4:39 pm**

Tranks.

Posted: **Tue Sep 26, 2023 3:48 pm**

Have similar problem in my EVE-NG lab. When i try to establish BGP connection between two adjacent routers, for local. and remote. addresses I'm using routers loopbacks, as result BGP sessions in down and /routing/bfd/session print show:

@R1] > routing/bfd/session/print
Flags: U - up, I - inactive
0 I ;;; BFD forbidden for destination address
multihop=yes vrf=main remote-address=10.0.0.2 local-address=10.0.0.1
desired-tx-interval=0ms required-min-rx=0ms multiplier=0

1 U multihop=no vrf=main remote-address=192.168.0.2%ether3
local-address=192.168.0.1 state=up state-changes=2 uptime=8s
desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms
remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s
packets-rx=46 packets-tx=43

Adding and specifying allowed address-list under bfd configuration doesn't help neither
But when i configure bgp session with ip which is configured directly on interface, the bgp and bfd is up

Can anyone confirm, that this is expected behaviour in ROS7.11.2 or I'm doing something wrong?

Posted: **Thu Nov 02, 2023 5:31 am**

I'm having the same issue with ROS 7.11.2.

Multihop BGP session is not established when I try to enable BFD for that session. BFD shows BFD forbidden for destination address. In my case the IP address is on the physical interface (not on loopback), but it is a different address because of the multihop BGP. I've tried adding both the remote IP address and the gateway to the BFD address-list, but no luck.

Posted: **Thu Nov 02, 2023 9:03 am**

Adding and specifying allowed address-list under bfd configuration doesn't help neither
But when i configure bgp session with ip which is configured directly on interface, the bgp and bfd is up

Show your bfd config.

Posted: **Thu Nov 02, 2023 11:50 am**

Hello mrz!

I will post entire configurations of both routers and here it is.

# ROUTER1 
/interface bridge
add name=loopback0 protocol-mode=none
/interface ethernet
set [ find default-name=ether1 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether2 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether3 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether4 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether5 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
/routing ospf instance
add disabled=no name=ospf-instance-v2 router-id=10.0.0.1
/routing ospf area
add comment=backbone_v2 disabled=no instance=ospf-instance-v2 name=area0
/ip address
add address=10.0.0.1 interface=loopback0 network=10.0.0.1
add address=192.168.1.1/30 comment=to-r4 interface=ether1 network=192.168.1.0
add address=192.168.2.1/30 comment=to-r3 interface=ether2 network=192.168.2.0
add address=192.168.0.1/30 comment=to-r2-rr interface=ether3 network=192.168.0.0
/ip dhcp-client
add interface=ether1
/ip firewall address-list
add address=192.168.0.0/16 list=bfd-allowed
add address=10.0.0.0/24 list=bfd-allowed

/routing bfd configuration
add address-list=bfd-allowed disabled=no forbid-bfd=no interfaces=all
/routing bgp connection
add as=65000 cluster-id=1.1.1.1 connect=yes listen=yes local.address=10.0.0.1 \
    .role=ibgp name=to-r2-rr remote.address=10.0.0.2 .as=65000 router-id=10.0.0.1 \
    use-bfd=yes
add as=65000 connect=yes listen=yes local.address=10.0.0.1 .role=ibgp-rr name=\
    to-r3-rr-client remote.address=10.0.0.3 .as=65000 router-id=10.0.0.1 use-bfd=\
    yes
add as=65000 connect=yes listen=yes local.address=10.0.0.1 .role=ibgp-rr name=\
    to-r4-rr-client remote.address=10.0.0.4 .as=65000 router-id=10.0.0.1 use-bfd=\
    yes
/routing ospf interface-template
add area=area0 disabled=no interfaces=loopback0 passive type=ptp
add area=area0 disabled=no interfaces=ether1 type=ptp use-bfd=yes
add area=area0 disabled=no interfaces=ether2 type=ptp use-bfd=yes
add area=area0 disabled=no interfaces=ether3 type=ptp use-bfd=yes
/system identity
set name=R1


[admin@R1] > routing/bfd/session/print 
Flags: U - up, I - inactive 
 0 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.2 local-address=10.0.0.1 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 1 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.3 local-address=10.0.0.1 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 2 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.4 local-address=10.0.0.1 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 3 U multihop=no vrf=main remote-address=192.168.1.2%ether1 
     local-address=192.168.1.1%ether1 state=up state-changes=2 uptime=5m59s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=2082 packets-tx=2684 

 4 U multihop=no vrf=main remote-address=192.168.2.2%ether2 
     local-address=192.168.2.1%ether2 state=up state-changes=2 uptime=5m8s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=1786 packets-tx=2442 

 5 U multihop=no vrf=main remote-address=192.168.0.2%ether3 
     local-address=192.168.0.1%ether3 state=up state-changes=1 uptime=14m42s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=5123 packets-tx=5124 
    



#ROUTER2 
/interface bridge
add name=loopback0 protocol-mode=none
/interface ethernet
set [ find default-name=ether1 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether2 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether3 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether4 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
set [ find default-name=ether5 ] advertise=10M-half,10M-full,100M-half,100M-full \
    disable-running-check=no
/routing ospf instance
add disabled=no name=ospf-instance-v2 router-id=10.0.0.2
/routing ospf area
add comment=backbone_v2 disabled=no instance=ospf-instance-v2 name=area0
/ip address
add address=10.0.0.2 interface=loopback0 network=10.0.0.2
add address=192.168.4.1/30 comment=to-r3 interface=ether1 network=192.168.4.0
add address=192.168.3.1/30 comment=to-r4 interface=ether2 network=192.168.3.0
add address=192.168.0.2/30 comment=to-r1-rr interface=ether3 network=192.168.0.0
/ip dhcp-client
add interface=ether1
/ip firewall address-list
add address=192.168.0.0/16 list=bfd-allowed
add address=10.0.0.0/24 list=bfd-allowed

/routing bfd configuration
add address-list=bfd-allowed disabled=no forbid-bfd=no interfaces=all
/routing bgp connection
add as=65000 cluster-id=1.1.1.1 connect=yes listen=yes local.address=10.0.0.2 \
    .role=ibgp name=to-r1-rr remote.address=10.0.0.1 .as=65000 router-id=10.0.0.2 \
    use-bfd=yes
add as=65000 connect=yes listen=yes local.address=10.0.0.2 .role=ibgp-rr name=\
    to-r3-rr-client remote.address=10.0.0.3 .as=65000 router-id=10.0.0.2 use-bfd=\
    yes
add as=65000 connect=yes listen=yes local.address=10.0.0.2 .role=ibgp-rr name=\
    to-r4-rr-client remote.address=10.0.0.4 .as=65000 router-id=10.0.0.2 use-bfd=\
    yes
/routing ospf interface-template
add area=area0 disabled=no interfaces=loopback0 passive type=ptp
add area=area0 disabled=no interfaces=ether1 type=ptp use-bfd=yes
add area=area0 disabled=no interfaces=ether2 type=ptp use-bfd=yes
add area=area0 disabled=no interfaces=ether3 type=ptp use-bfd=yes
/system identity
set name=R2


[admin@R2] > routing/bfd/session/print 
Flags: U - up, I - inactive 
 0 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.1 local-address=10.0.0.2 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 1 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.3 local-address=10.0.0.2 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 2 I ;;; BFD forbidden for destination address
     multihop=yes vrf=main remote-address=10.0.0.4 local-address=10.0.0.2 
     desired-tx-interval=0ms required-min-rx=0ms multiplier=0 

 3 U multihop=no vrf=main remote-address=192.168.4.2%ether1 
     local-address=192.168.4.1%ether1 state=up state-changes=2 uptime=16m21s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=5701 packets-tx=6501 

 4 U multihop=no vrf=main remote-address=192.168.3.2%ether2 
     local-address=192.168.3.1%ether2 state=up state-changes=2 uptime=17m12s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=5991 packets-tx=6728 

 5 U multihop=no vrf=main remote-address=192.168.0.1%ether3 
     local-address=192.168.0.2%ether3 state=up state-changes=2 uptime=25m56s 
     desired-tx-interval=200ms actual-tx-interval=200ms required-min-rx=200ms 
     remote-min-rx=200ms remote-min-tx=200ms multiplier=5 hold-time=1s 
     packets-rx=9030 packets-tx=9035

Adding and specifying allowed address-list under bfd configuration doesn't help neither
But when i configure bgp session with ip which is configured directly on interface, the bgp and bfd is up
Show your bfd config.

Posted: **Thu Nov 02, 2023 11:56 am**

Do not specify interface if you wan to match multihop sessions.

Posted: **Thu Nov 02, 2023 12:07 pm**

Thank you mrz, it helped, bfd and bgp sessions are up now.

[admin@R1] /routing/bfd> session/print 
Flags: U - up, I - inactive 
 0 U multihop=yes vrf=main remote-address=10.0.0.2 local-address=10.0.0.1 state=up 
     state-changes=2 uptime=48s desired-tx-interval=200ms actual-tx-interval=200ms 
     required-min-rx=200ms remote-min-rx=200ms remote-min-tx=200ms multiplier=5 
     hold-time=1s packets-rx=280 packets-tx=277

Do not specify interface if you wan to match multihop sessions.

MikroTik

RouterOS V7 does not work BGP multihop peer

RouterOS V7 does not work BGP multihop peer

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Re: RouterOS V7 does not work BGP multihop peer

Re: RouterOS V7 does not work BGP multihop peer

Re: RouterOS V7 does not work BGP multihop peer

Re: RouterOS V7 does not work BGP multihop peer

Re: RouterOS V7 does not work BGP multihop peer