```
---
### Author:  [@mriganksc](https://forum.networklessons.com/u/mriganksc)
#### Post date: [April 4, 2018, 4:30am UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/5 "2018-04-04T04:30:02Z")
Thanks a lot. I will try to implement the suggested configuration and let you know, whether it works.
---
### Author:  [@mriganksc](https://forum.networklessons.com/u/mriganksc)
#### Post date: [April 4, 2018, 2:39pm UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/6 "2018-04-04T14:39:47Z")
Getting following error on R3:
`Apr 4 14:31:02.439: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.0.18, FastEthernet0/0`
Configuration of R3 is as follows:
```
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
archive
log config
hidekeys
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
interface Loopback3
ip address 3.3.3.3 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.0.17 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.0.10 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet1/0
ip address 192.168.0.14 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet1/1
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet2/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet2/1
no ip address
shutdown
duplex auto
speed auto
!
router ospf 1
log-adjacency-changes
area 3 virtual-link 4.4.4.4
network 192.168.0.8 0.0.0.3 area 0
network 192.168.0.12 0.0.0.3 area 0
network 192.168.0.16 0.0.0.3 area 3
default-information originate always
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
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
!
end
```
Configuration of R4 is as follows:
```
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R4
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
archive
log config
hidekeys
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
interface Loopback4
ip address 4.4.4.4 255.255.255.255
!
interface FastEthernet0/0
ip address 192.168.0.18 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.0.21 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet1/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet1/1
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet2/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet2/1
no ip address
shutdown
duplex auto
speed auto
!
router ospf 1
log-adjacency-changes
area 3 virtual-link 3.3.3.3
network 192.168.0.16 0.0.0.3 area 3
network 192.168.0.20 0.0.0.3 area 4
default-information originate always
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
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
!
end
```
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [April 5, 2018, 9:32am UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/7 "2018-04-05T09:32:59Z")
Hi Mriganksc,
The configuration looks OK. Two things you might want to check:
- Are the router IDs correct? If you added those loopbacks after starting OSPF then you will still have the old router ID. Use `show ip protocols | include Router ID` to verify this.
- Are the links on R3 in area 0 active? If not, your virtual link will not appear.
Rene
---
### Author:  [@mriganksc](https://forum.networklessons.com/u/mriganksc)
#### Post date: [April 7, 2018, 3:35pm UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/8 "2018-04-07T15:35:32Z")
[R1\_i1\_startup-config.txt](https://cdn-forum.networklessons.com/uploads/default/original/1X/f746d28927efa866dd3ba5015323acfba77e6221.txt) (1.4 KB)
[R2\_i2\_startup-config.txt](https://cdn-forum.networklessons.com/uploads/default/original/1X/e4a65fb477d1e9a291e3a98c5e2f2a7d4d732bbc.txt) (1.4 KB)
[R3\_i3\_startup-config.txt](https://cdn-forum.networklessons.com/uploads/default/original/1X/4ebe9a6c874f24e6a6b0c6e5efe24917a75aac1d.txt) (1.4 KB)
[R4\_i4\_startup-config.txt](https://cdn-forum.networklessons.com/uploads/default/original/1X/ce5c580a4d71e8597434e7e6dd88c75ff09c1bed.txt) (1.4 KB)
[R5\_i5\_startup-config.txt](https://cdn-forum.networklessons.com/uploads/default/original/1X/11a35ef5d10c0f6151198bc29d9644970b293ee3.txt) (1.3 KB)
Hi Rene,
I am able to reach 10.10.60.1 from R5 but getting no reply from PC1 i.e 10.10.60.100. Router configurations are shared.
---
### Author:  [@mriganksc](https://forum.networklessons.com/u/mriganksc)
#### Post date: [April 7, 2018, 5:10pm UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/9 "2018-04-07T17:10:48Z")
issue resolved. Replaced Docker Ubuntu Host (PC1) with VPC.
(Y)
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [April 12, 2018, 6:06pm UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/10 "2018-04-12T18:06:18Z")
Good to hear you found it.
When you are playing with networking protocols, It’s best to keep it simple…if you just want to test connectivity, it’s easier to use a router (with IP routing disabled) as a host and use that to ping from one end to another.
When you use a Windows PC, there’s the firewall that could mess things up…with something like Docker, there are a couple of things that could go wrong. Keep it simple 🙂
---
### Author:  [@lagapidis](https://forum.networklessons.com/u/lagapidis)
#### Post date: [August 5, 2019, 8:10am UTC](https://forum.networklessons.com/t/ospf-virtual-link/3373/11 "2019-08-05T08:10:10Z")
A post was merged into an existing topic: [OSPF Virtual Link Authentication](https://forum.networklessons.com/t/ospf-virtual-link-authentication/2657/10)