to solve this problem?
For DNS in such situations I start unbound locally and bind it to
an internal interface or an IP on lo0 and then tell unbound to
just use that IP only (outgoing-interface IIRC) that is
advertised out as a work around. Its not a proper solution, but
will get your resolver working at least. I run into this problem
in layered networks where the next hop is often RFC 1918 addrs. I
bind applications to internal NICs that have addresses that have
routing to/from.
---Mike