Configuring Tunnels with the Same Source Address (Bug ID 4152864)

Bug ID 4152864 describes problems that occur when two tunnels are configured with the same tunnel source address, which is a serious issue for 6to4 tunnels.

Do not configure a 6to4 tunnel and an automatic tunnel (atun) with the same tunnel source address. For information about automatics and the atun command, refer to the tun(7M) man page.