I am in a situation where I want to terminate any tunnels at one device. I.e. I want to be able to create a tunnel to this device from any source ip adress.
Something which can inspect a packet, see that it is a tunnel (IP-in-IP or GRE works fine for me) destined for this host, strip of the outer header and forward it by the inner header would be fine for my purposes.
I would suggestions both which are doable within Linux or/and with a Cisco Nexus 3000 device.
Are there any support for this?
Example:
Suppose Alice wants to send a packet to Bob. Suppose Carol has such a terminate-any-tunnel capability described above.
Alice could then send the following packet
# Outer IP header
Dest: Carol
Source: Alice
# Inner IP header
Dest: Bob
Source: Alice
# Payload
Carol will check that the packet is destined for her, strip off the outer header and route the remaining packet with the default routing rules.
# IP header
Dest: Bob
Source: Alice
# Payload
Note that we did not have to configure anything specific on Carol's side (other than initially).
