If mroutes are permitted:

R2#sh run int tu 0
Building configuration...

Current configuration : 157 bytes
!
interface Tunnel0
 ip address 24.24.24.2 255.255.255.0
 ip pim sparse-dense-mode
 keepalive 10 3
 tunnel source Loopback0
 tunnel destination 4.4.4.4
end




R4(config)#do sh run int tu 0
Building configuration...

Current configuration : 157 bytes
!
interface Tunnel0
 ip address 24.24.24.4 255.255.255.0
 ip pim sparse-dense-mode
 keepalive 10 3
 tunnel source Loopback0
 tunnel destination 2.2.2.2
end




R4#sh run | i ip mroute
ip mroute 0.0.0.0 0.0.0.0 Tunnel0
R4#