Solved: Tunnel status up but protocol down

ss571 · ‎01-18-2024

Here is my topology in gns3:

I plan to form a tunnel between R3 and R4, and the loopback and tunnel interface is as shown next to the routers. I've set the tunnel source and destination for both routers with the loopback interfaces, and all physical and loopback interfaces are up for R1-4. The MTU value for both routers is the same too. But when I checked the "sh ip int br" for R3 and R4, the tunnel interface status is up, but protocol is down. May I know why is this occurring?

Below are the sh ip int br for R3 and R4:

MHM Cisco World · ‎01-18-2024

As I guess
never use same IGP for both tunnel and it is tunnel source
here you use OSPF 1 for tunnel and for tunnel source (looback which is no correct add to OSPF)
so what you need is
A-interface loopback

ip ospf network point-to-point

<<- you need to add this in both router
B-router ospf 1 <<- you need to add this in both router

net <LO IP> area 0

C-router ospf 10 <<- you need to add this in both router

net <tunnel IP> area 0

why need two separate OSPF ?
https://study-ccnp.com/gre-tunnels-recursive-routing-problems/

MHM

View solution in original post

MHM Cisco World · ‎01-18-2024

you need to be sure that the LO is reachable otherwise the tunnel is DOWN
MHM

ss571 · ‎01-18-2024

LO meaning the loopback int? I apologize for my lack of knowledge as I'm new to this field

MHM Cisco World · ‎01-18-2024

Yes correct LO is loopback
show route in both routers
check if you see LO of other router
MHM

ss571 · ‎01-18-2024

No i don't see the LO for R4 in show route in R4

M02@rt37 · ‎01-18-2024

Hello @ss571

Add static route on R3 R1 R2 and R4 in order to route Loopback interfaces. You should be able to ping Loopack on each routers R3 and R4.

@MHM Cisco World give you the rigth answer.

Best regards
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ss571 · ‎01-18-2024

Also is it a need to add in the static routes in R3 and R4 for the tunnel to work?

MHM Cisco World · ‎01-18-2024

you need static route only for LO to make reachable
when it reachable the Tunnel will be UP/UP and appear in both routers as connect
MHM

ss571 · ‎01-18-2024

Btw In R1 and R2 there is ospf configured as well, do i add the networks in the ospf or add in the addresses as the neighbours?

MHM Cisco World · ‎01-18-2024

can I see the config of R1 and R2
thanks
MHM

ss571 · ‎01-18-2024

Yeah sure, here they are:

R1

upgrade fpd auto
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
!
!
!
!
!
!
no ip domain lookup
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
redundancy
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
 ip address 148.90.255.33 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 hold-queue 150 in
!
interface FastEthernet0/0
 ip address 148.90.255.37 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 duplex half
!
interface GigabitEthernet1/0
 ip address 148.90.255.14 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 10
 negotiation auto
!
interface GigabitEthernet2/0
 ip address 148.90.255.2 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 negotiation auto
!
interface GigabitEthernet3/0
 ip address 148.90.255.17 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 negotiation auto
!
interface GigabitEthernet4/0
 ip address 148.90.255.25 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 10
 negotiation auto
!
interface GigabitEthernet5/0
 no ip address
 negotiation auto
 channel-group 1
!
interface GigabitEthernet6/0
 no ip address
 negotiation auto
 channel-group 1
!
router ospf 1
 network 148.90.252.0 0.0.0.255 area 20
 network 148.90.253.0 0.0.0.255 area 20
 network 148.90.254.0 0.0.0.255 area 20
 network 148.90.255.0 0.0.0.3 area 0
 network 148.90.255.12 0.0.0.3 area 0
 network 148.90.255.16 0.0.0.3 area 0
 network 148.90.255.24 0.0.0.3 area 0
 network 148.90.255.32 0.0.0.3 area 0
 network 148.90.255.36 0.0.0.3 area 0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
mgcp profile default
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line vty 0 4
 login
 transport input all
!
!
end

ss571 · ‎01-18-2024

Here is R2:

upgrade fpd auto
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
!
!
!
!
!
!
no ip domain lookup
ip cef
ipv6 unicast-routing
ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
redundancy
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
 ip address 148.90.255.34 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 10
 ipv6 address 2001:148:90:2::16/127
 ipv6 ospf 1 area 0
 hold-queue 150 in
!
interface FastEthernet0/0
 ip address 148.90.255.41 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 duplex half
!
interface GigabitEthernet1/0
 ip address 148.90.255.10 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 10
 negotiation auto
 ipv6 address 2001:148:90:2::5/127
 ipv6 ospf 1 area 0
!
interface GigabitEthernet2/0
 ip address 148.90.255.6 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 1
 negotiation auto
 ipv6 address 2001:148:90:2::3/127
 ipv6 ospf 1 area 0
!
interface GigabitEthernet3/0
 ip address 148.90.255.21 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 1
 negotiation auto
 ipv6 address 2001:148:90:2::13/127
 ipv6 ospf 1 area 0
!
interface GigabitEthernet4/0
 ip address 148.90.255.29 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 ip ospf cost 10
 negotiation auto
 ipv6 address 2001:148:90:2::11/127
 ipv6 ospf 1 area 0
!
interface GigabitEthernet5/0
 no ip address
 negotiation auto
 channel-group 1
!
interface GigabitEthernet6/0
 no ip address
 negotiation auto
 channel-group 1
!
router ospf 1
 area 0 authentication
 network 148.90.255.4 0.0.0.3 area 0
 network 148.90.255.8 0.0.0.3 area 0
 network 148.90.255.20 0.0.0.3 area 0
 network 148.90.255.28 0.0.0.3 area 0
 network 148.90.255.32 0.0.0.3 area 0
 network 148.90.255.40 0.0.0.3 area 0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
ipv6 router ospf 1
!
!
!
!
control-plane
!
!
!
mgcp profile default
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line vty 0 4
 login
 transport input all
!
!
end

ss571 · ‎01-18-2024

Btw now R3 tunnel protocol is up, but R4 protocol is still down

MHM Cisco World · ‎01-18-2024

I need to see also R3 and R4 config
thanks
MHM

ss571 · ‎01-18-2024

Alright, here is R3:

upgrade fpd auto
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
!
!
!
!
!
!
no ip domain lookup
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
redundancy
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
interface Loopback0
 ip address 148.90.255.253 255.255.255.252
!
interface Tunnel0
 no ip address
!
interface Tunnel1
 ip address 192.168.0.1 255.255.255.252
 ip mtu 1400
 tunnel source 148.90.255.253
 tunnel destination 148.90.255.254
!
interface FastEthernet0/0
 ip address 148.90.255.38 255.255.255.252
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 key
 duplex half
!
interface GigabitEthernet1/0
 ip address 148.91.0.1 255.255.255.252
 negotiation auto
!
interface GigabitEthernet2/0
 no ip address
 shutdown
 negotiation auto
!
interface GigabitEthernet3/0
 no ip address
 shutdown
 negotiation auto
!
interface GigabitEthernet4/0
 no ip address
 shutdown
 negotiation auto
!
interface GigabitEthernet5/0
 no ip address
 shutdown
 negotiation auto
!
interface GigabitEthernet6/0
 no ip address
 shutdown
 negotiation auto
!
router ospf 1
 network 148.90.255.36 0.0.0.3 area 0
 network 148.90.255.252 0.0.0.3 area 0
 network 192.168.0.0 0.0.0.3 area 0
 default-information originate
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
control-plane
!
!
!
mgcp profile default
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line vty 0 4
 login
 transport input all
!
!
end