View source for Mikrotik 7: BGP Sedehana

[[File:Bgp-multihoming.png|center|400px|thumb]]

Sambungan

 ISP1:
 eth0  --> ISP3 eth0
 eth1  --> ISP2 eth1

 ISP2
 eth0  --> ISP3 eth1
 eth1  --> ISP1 eth1

 ISP3
 eth0  --> ISP1 eth0
 eth1  --> ISP2 eth0




Ada tiga (3) ISP

ISP1:
 IP 192.168.1.1/24 menuju ISP3
 IP 192.168.3.1/24 menuju ISP2
 AS 10
 IP 10.100.100.0/24
 IP 10.100.200.0/24

ISP2
 IP 192.168.2.1/24 - menuju ISP3
 IP 192.168.3.2/24 - menuju ISP1
 AS 20
 IP 10.10.10.0/24
 IP 10.10.20.0/24

ISP3 (kita)
 IP 192.168.1.2/24 - menuju ISP1
 IP 192.168.2.2/24 - menuju ISP2
 AS 30
 IP 10.1.1.0/24
 IP 10.1.2.0/24 


Berikut konfigurasi **MikroTik RouterOS v7** yang rapi untuk **ISP1, ISP2, ISP3** sesuai topologi pada file: ISP1 AS10, ISP2 AS20, ISP3 AS30; masing-masing punya dua koneksi BGP dan dua network lokal. 

Prinsip filter sederhana:

* **Input filter:** `accept;` semua route dari peer.
* **Output filter:** hanya advertise network lokal sendiri.
* **Tidak perlu blackhole route** karena network lokal sudah ada sebagai *connected route* dari `ether3` dan `ether4`.



==ISP1 — AS 10==


 # =========================
 # ISP1 - RouterOS v7
 # AS 10
 # =========================
 
 # IP address
 /ip address
 add interface=ether1 address=192.168.1.1/24 comment="to ISP3"
 add interface=ether2 address=192.168.3.1/24 comment="to ISP2"
 add interface=ether3 address=10.100.100.1/24 comment="LAN 10.100.100.0/24"
 add interface=ether4 address=10.100.200.1/24 comment="LAN 10.100.200.0/24"
 
 # BGP local AS
 /routing bgp template
 set default as=10
 
 # BGP connections
 /routing bgp connection
 add name=toISP3 remote.address=192.168.1.2 remote.as=30 local.role=ebgp templates=default
 add name=toISP2 remote.address=192.168.3.2 remote.as=20 local.role=ebgp templates=default
 
 # Advertised local networks
 /ip firewall address-list
 add list=bgp-networks address=10.100.100.0/24
 add list=bgp-networks address=10.100.200.0/24
 
 # Simple input filters: accept all received routes
 /routing filter rule
 add chain=isp2-in rule="accept;"
 add chain=isp3-in rule="accept;"
 
 # Simple output filters: advertise only ISP1 local prefixes
 /routing filter rule
 add chain=isp2-out rule="if (dst in 10.100.100.0/24) { accept; }"
 add chain=isp2-out rule="if (dst in 10.100.200.0/24) { accept; }"
 add chain=isp2-out rule="reject;"
 
 add chain=isp3-out rule="if (dst in 10.100.100.0/24) { accept; }"
 add chain=isp3-out rule="if (dst in 10.100.200.0/24) { accept; }"
 add chain=isp3-out rule="reject;"

 # Apply filters and advertised networks
 /routing bgp connection
 set toISP2 output.network=bgp-networks input.filter=isp2-in output.filter-chain=isp2-out
 set toISP3 output.network=bgp-networks input.filter=isp3-in output.filter-chain=isp3-out


==ISP2 — AS 20==


 # =========================
 # ISP2 - RouterOS v7
 # AS 20
 # =========================
 
 # IP address
 /ip address
 add interface=ether1 address=192.168.2.1/24 comment="to ISP3"
 add interface=ether2 address=192.168.3.2/24 comment="to ISP1"
 add interface=ether3 address=10.10.10.1/24 comment="LAN 10.10.10.0/24"
 add interface=ether4 address=10.10.20.1/24 comment="LAN 10.10.20.0/24"
 
 # BGP local AS
 /routing bgp template
 set default as=20
 
 # BGP connections
 /routing bgp connection
 add name=toISP1 remote.address=192.168.3.1 remote.as=10 local.role=ebgp templates=default
 add name=toISP3 remote.address=192.168.2.2 remote.as=30 local.role=ebgp templates=default
 
 # Advertised local networks
 /ip firewall address-list
 add list=bgp-networks address=10.10.10.0/24
 add list=bgp-networks address=10.10.20.0/24
 
 # Simple input filters: accept all received routes
 /routing filter rule
 add chain=isp1-in rule="accept;"
 add chain=isp3-in rule="accept;"
 
 # Simple output filters: advertise only ISP2 local prefixes
 /routing filter rule
 add chain=isp1-out rule="if (dst in 10.10.10.0/24) { accept; }"
 add chain=isp1-out rule="if (dst in 10.10.20.0/24) { accept; }"
 add chain=isp1-out rule="reject;"
 
 add chain=isp3-out rule="if (dst in 10.10.10.0/24) { accept; }"
 add chain=isp3-out rule="if (dst in 10.10.20.0/24) { accept; }"
 add chain=isp3-out rule="reject;"
 
 # Apply filters and advertised networks
 /routing bgp connection
 set toISP1 output.network=bgp-networks input.filter=isp1-in output.filter-chain=isp1-out
 set toISP3 output.network=bgp-networks input.filter=isp3-in output.filter-chain=isp3-out


==ISP3 — AS 30==

 # =========================
 # ISP3 - RouterOS v7
 # AS 30
 # =========================
 
 # IP address
 /ip address
 add interface=ether1 address=192.168.1.2/24 comment="to ISP1"
 add interface=ether2 address=192.168.2.2/24 comment="to ISP2"
 add interface=ether3 address=10.1.1.1/24 comment="LAN 10.1.1.0/24"
 add interface=ether4 address=10.1.2.1/24 comment="LAN 10.1.2.0/24"
 
 # BGP local AS
 /routing bgp template
 set default as=30
 
 # BGP connections
 /routing bgp connection
 add name=toISP1 remote.address=192.168.1.1 remote.as=10 local.role=ebgp templates=default
 add name=toISP2 remote.address=192.168.2.1 remote.as=20 local.role=ebgp templates=default
 
 # Advertised local networks
 /ip firewall address-list
 add list=bgp-networks address=10.1.1.0/24
 add list=bgp-networks address=10.1.2.0/24
 
 # Simple input filters: accept all received routes
 /routing filter rule
 add chain=isp1-in rule="accept;"
 add chain=isp2-in rule="accept;"
 
 # Simple output filters: advertise only ISP3 local prefixes
 /routing filter rule
 add chain=isp1-out rule="if (dst in 10.1.1.0/24) { accept; }"
 add chain=isp1-out rule="if (dst in 10.1.2.0/24) { accept; }"
 add chain=isp1-out rule="reject;"
 
 add chain=isp2-out rule="if (dst in 10.1.1.0/24) { accept; }"
 add chain=isp2-out rule="if (dst in 10.1.2.0/24) { accept; }"
 add chain=isp2-out rule="reject;"
 
 # Apply filters and advertised networks
 /routing bgp connection
 set toISP1 output.network=bgp-networks input.filter=isp1-in output.filter-chain=isp1-out
 set toISP2 output.network=bgp-networks input.filter=isp2-in output.filter-chain=isp2-out



==Command pengecekan==

Jalankan di masing-masing router:


 /routing bgp session print

Harus muncul flag:

 E

Artinya **established**.

Cek route BGP yang diterima:

 /ip route print where bgp


atau:

 /routing route print where bgp


Cek filter:

 /routing filter rule print

Cek advertised address-list:

 /ip firewall address-list print where list=bgp-networks



==Catatan penting==

Kalau muncul:

 failure: already have such address


artinya IP tersebut sudah ada. Tidak perlu ditambahkan ulang.

Kalau muncul:

 failure: already have such entry


artinya address-list sudah ada. Tidak perlu ditambahkan ulang.

Kalau muncul:

 no such item


biasanya karena nama connection salah. Gunakan:

 /routing bgp connection print

Lalu pastikan perintah `set` memakai nama yang benar, misalnya:

 set toISP1 ...
 set toISP2 ...
 set toISP3 ...

bukan:

 set isp1 ...
 set isp2 ...
 set isp3 ...