We have the following config in Cisco 2811:
interface FastEthernet0/1
ip address 10.1.2.1 255.255.255.0 secondary
ip address 10.90.11.1 255.255.255.0 secondary
ip nat inside
(10.90.11.0/24 goes via IPSec to another routers)
ip nat inside source list 101 interface FastEthernet0/0 overload
ip nat inside source list 103 interface FastEthernet0/0 overload
access-list 101 permit ip 10.1.2.0 0.0.0.255 any
access-list 103 deny ip 10.90.11.0 0.0.0.255 10.90.0.0 0.0.255.255
access-list 103 permit ip 10.90.11.0 0.0.0.255 any
Everything works. The host inside 10.90.11.0/24 and the hosts in 10.90.* networks connected via IPSec can see each others, the remote routers can see this Cisco 2811 as well.
But Cisco can't see any router or host except a host in the local 10.90.11.0/24. Small but annoying problem.
How can I solve this?
This is most probably because when you try to ping(?), .. remote host from the cisco device the source IP is not 10.90.11.1
If you run a ping, try doing an extended ping to only running "ping" you will be asked for the source internet/ip to use, put 10.90.11.1 and it should work