A Simple MikroTik RouterOS v7 BGP Config

While I’m not a professional network engineer at the time of writing, lately I’ve been playing with MikroTik’s CHR in EVE-NG.

One thing I wanted to set up is a basic BGP configuration between two ASes. In this setup, I will assume there are two neighboring routers with eBGP.

The setup will have:

  • R1 with AS1 and R2 with AS2
  • 1.0.0.0/24 that R1 will advertise
  • 2.0.0.0/24 that R2 will advertise
  • 3.0.0.0/24 for the point-to-point link between R1 and R2
  • 3.0.0.1 for R1 and 3.0.0.2 for R2
  • The ether1 interface for the R1 and R2 point-to-point links
  • The ether2 interface for the internal, to-be-advertised subnet

I will not be doing route filters or IPv6 in this article. I plan to do it in future posts.

To setup BGP, first set your IP addresses, on R1:

/ip address
add address=1.0.0.1/24 interface=ether2 network=1.0.0.0
add address=3.0.0.1/24 interface=ether1 network=3.0.0.0

On R2:

/ip address
add address=2.0.0.1/24 interface=ether2 network=2.0.0.0
add address=3.0.0.2/24 interface=ether1 network=3.0.0.0

Then configure the IP address lists, on R1:

/ip firewall address-list
add address=1.0.0.0/24 list=bgp-networks
add address=3.0.0.0/24 list=bgp-networks
/ip route
add blackhole dst-address=1.0.0.0/24

On R2:

/ip firewall address-list
add address=2.0.0.0/24 list=bgp-networks
/ip route
add blackhole dst-address=2.0.0.0/24

Next, we should configure the default AS, on R1:

/routing bgp template
set default as=1

On R2:

/routing bgp template
set default as=2

Finally, configure BGP, on R1:

/routing bgp connection
add listen=yes local.role=ebgp name=toR2 output.network=bgp-networks \
    remote.address=3.0.0.2 templates=default

On R2:

/routing bgp connection
add listen=yes local.role=ebgp name=toR1 output.network=bgp-networks \
    remote.address=3.0.0.1 templates=default

The BGP should now be set, on R1:

[admin@MikroTik] > /routing/bgp/connection print
Flags: D - dynamic, X - disabled, I - inactive 
 0   name="toR2" 
     remote.address=3.0.0.2 
     local.default-address=3.0.0.1 .role=ebgp 
     listen=yes routing-table=main templates=default as=1 
     output.network=bgp-networks 
[admin@MikroTik] > /routing bgp ad print
 0 peer=toR1-1 dst=2.0.0.0/24 afi=ip nexthop=3.0.0.2 origin=0 
   as-path=sequence 2
[admin@MikroTik] >

On R2:

[admin@MikroTik] > /routing/bgp/connection print
Flags: D - dynamic, X - disabled, I - inactive 
 0   name="toR1" 
     remote.address=3.0.0.1 
     local.default-address=3.0.0.2 .role=ebgp 
     listen=yes routing-table=main templates=default as=2 
     output.network=bgp-networks 
[admin@MikroTik] > /routing bgp ad print
 0 peer=toR1-1 dst=2.0.0.0/24 afi=ip nexthop=3.0.0.2 origin=0 
   as-path=sequence 2 
[admin@MikroTik] >