emerge world -uDNav --with-bdeps y

These are the packages that would be merged, in order:

Calculating dependencies... done!

Total: 0 packages, Size of downloads: 0 KiB

!!! The following update has been skipped due to unsatisfied dependencies:

net-firewall/shorewall:0

selected: net-firewall/shorewall-5.1.9:0/0::net-kit, installed
skipped: net-firewall/shorewall-5.1.9-r1:0/0::net-kit, ebuild scheduled for merge (see unsatisfied dependency below)

emerge: there are no ebuilds to satisfy ">=sys-apps/iproute2-4.4.0[-minimal]".
(dependency required by "net-firewall/shorewall-5.1.9-r1::net-kit" [ebuild])


Nothing to merge; quitting.