unable to get IPSec up from r2 to r4 with ospf routing

[lightning668]

hi all , im trying to configure ipsec tunnel from R2 to R4 (top right router) . but after i configured all the ipsec gre commands , my ospf routing seems to be down suddenly and now both my ipsec and ospf doesn't work. any one can help me please? i'm really lost after troubleshooting for hours. 

[marce1000]

 - 

1. Verify that the IPSec tunnel is properly configured on both R2 and R4. This includes checking that the IP addresses, encryption settings, and authentication methods are correctly configured and match on both sides.

2. Make sure that OSPF is correctly configured and working on both R2 and R4. You can check this by running the show ip ospf neighbor command on both devices and verifying that they have formed a neighbor relationship.

3. Check the routing tables on both R2 and R4 to ensure that there are valid routes between the devices over the IPSec tunnel. You can do this with the show ip route command.

4. Check the firewall and access control lists (ACLs) on both R2 and R4 to ensure that traffic is not being blocked between the devices.

5. Check the status of the IPSec tunnel with the show crypto isakmp sa and show crypto ipsec sa commands on both R2 and R4. This will show you the current status of the IPSec security associations (SAs) and can help you identify any issues with the tunnel.

 M.

[lightning668]

hi marce, 

my ospf neighbor was up until the crypto map was applied to the interface. not sure why this happens. any idea why ? im running ospf authentication

[marce1000]

                      >....until the crypto map was applied to the interface. 
 - Check logs on the involved devices when this is  done , look for additional info's

 M.