Routage statique et dynamique

! Route statique simple
ip route {{TARGET}} 255.255.255.0 {{SERVER_IP}}
! Route par défaut
ip route 0.0.0.0 0.0.0.0 {{SERVER_IP}}
! Route flottante (backup — distance administrative plus haute)
ip route 10.0.0.0 255.255.0.0 192.168.2.1 200   ! AD 200 > 1 (statique)
! Route vers interface (PPP/serial)
ip route 0.0.0.0 0.0.0.0 Serial0/0
! Vérifier
show ip route
show ip route static
show ip route 10.0.0.0

! Activer OSPF
conf t
router ospf 1
 router-id 1.1.1.1
 network 192.168.1.0 0.0.0.255 area 0
 network 10.0.0.0 0.0.0.255 area 0
 passive-interface GigabitEthernet0/1   ! ne pas envoyer de hello
! Sur les interfaces
interface GigabitEthernet0/0
 ip ospf 1 area 0
 ip ospf cost 10
 ip ospf priority 100    ! DR/BDR election
! OSPF authentification (MD5)
interface GigabitEthernet0/0
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 {{PASSWORD}}
! Redistribuer les routes statiques dans OSPF
router ospf 1
 redistribute static subnets
! Vérifier
show ip ospf neighbor
show ip ospf database
show ip ospf interface brief
show ip route ospf
debug ip ospf events

! Configurer eBGP
conf t
router bgp {{ASN}}
 bgp router-id 1.1.1.1
 neighbor {{SERVER_IP}} remote-as {{ASN}}  ! Peer AS
 
! Annoncer un réseau
router bgp {{ASN}}
 network 203.0.113.0 mask 255.255.255.0
! iBGP (même AS)
router bgp {{ASN}}
 neighbor 10.0.0.2 remote-as {{ASN}}
 neighbor 10.0.0.2 update-source Loopback0
 neighbor 10.0.0.2 next-hop-self
! Route Reflector (iBGP full mesh alternative)
router bgp {{ASN}}
 neighbor 10.0.0.2 route-reflector-client
 neighbor 10.0.0.3 route-reflector-client
! Vérifier
show bgp summary
show bgp neighbors {{SERVER_IP}}
show ip bgp
show ip bgp 203.0.113.0

Ordre de prfrence mnmonique We Love Oranges AS Oranges Mean Pure Refreshment 
1 Weight Cisco local plus haut  prfr
2 Local Preference plus haut  prfr dfaut 100
3 Locally Originated
4 AS Path plus court  prfr
5 Origin IGP < EGP < Incomplete
6 MED plus bas  prfr
7 eBGP > iBGP
8 IGP metric vers next-hop
9 Route la plus ancienne
10 Router-ID plus bas  prfr

! Ping étendu
ping 8.8.8.8 source GigabitEthernet0/0 repeat 100
! Traceroute
traceroute 8.8.8.8
traceroute ip 8.8.8.8 source GigabitEthernet0/0
! Table de routage filtrée
show ip route | include 192.168.
show ip route summary
! Interface stats
show interfaces GigabitEthernet0/0
show ip interface brief
! ARP
show arp
clear arp-cache
! Debug (attention en prod)
debug ip routing
debug ip ospf events
no debug all

# Voir la table de routage
ip route show
ip route get 8888   # quel chemin pour cette destination
# Ajouter une route
ip route add 10000/8 via {{SERVER_IP}} dev eth0
ip route add 10000/8 via {{SERVER_IP}} dev eth0 metric 100
# Route par défaut
ip route add default via {{SERVER_IP}}
# Supprimer
ip route del 10000/8
# Persistant (Debian/Ubuntu — /etc/network/interfaces ou netplan)
# Netplan (/etc/netplan/01-netcfg.yaml)
network
  ethernets
    eth0
      addresses 192168110/24
      gateway4 19216811
      routes
         to 10000/8
          via 1921681254