We use an 1841 with two DSL lines and do loadbalancing, which works okay for internet traffic. However, when we try to setup an IPSec tunnel to a distant internet location, the tunnel won't come up. If we disable loadbalancing and route all traffic over either one DSL line the tunnel workes fine. In both cases (with one or two lines) the tunnel source is the same loopback address.
How come the tunnel won't com up with loadbalanced WAN connections? I thought it might be that encaps'ed packets might arrive in wrong order.