What are possibilities in Linux kernel (?) to work with Cisco endpoint encorporating GRE keep-alives? We have GRE IPsec tunnel set up with another company. We would like to have backup tunnel which should be active when main one dies. So they enable GRE keep-alives on the first one which will detect failure and switch routing to the backup tunnel. We are dependent on technology proposed by them (another solutions can't be used). How can we accomplish such communication? I was surprised finding nothing about it in iproute2 nor kernel. Only this popped up, but it does not seem to be reliable for production use.
UPDATE:
Our current configuration is:
- Ubuntu server 14.04 LTS, kernel 3.13.0-24-generic
- racoon and setkey daemon for managing IPsec
- iproute2 for bringing tunnel up in gre mode
We must use GRE keep-alives. They told us there is no way (well, not technically, but I guess it's their policy) to establish backup tunnel unless we enable keep-alives.
The question is, is it possible using server configuration mentioned above?