I have issue setting up GRE IPsec transport mode to Cisco IOS router.
I confidently sure my IPsec setting, encryption and hashing, match the other side which reside on other company. the error shows there is a mismatch in encryption or hashing but after trying every possible scenarios I can't tell what's wrong with it. Although I change the advanced setting to " Prefer older IPsec SAs", the result was same.
Can anyone help me with this matter.
Thanks in advance.