I have a question regarding having multiple tunnels with different source IPs on the same device. My router supports, and I am using multi-wan for my IPv4 connections, IPSEC-GRE, etc but I cannot get two HE tunnels to work at the same time on the device. Is this supported, known to work, or am I barking up the wrong tree?
I assume that your multi-wan device has different IPv4 addresses on the wan interfaces. However, your use of IPSEC may interfere. That's not what the HE tunnels use, and if your IPSEC configuration requires authentication or encapsulation, that could reject the tunnelled packets using protocol 4 (IPv4 in IPv4).
Ah sorry for the confusion, I merely mentioned IPSEC on the IPv4 addresses as an indication that other services are working with both external addresses, just not 6to4 tunneling