Got an odd issue. I have a MS RRAS server running some client VPN connections. Every so often (and this seems to happen at a fairly regular frequency) users on the VPN will loose connectvity to the majority of a single VLAN. It's always the same VLAN. The VPN terminates at my Colo. The other VLANs are either local to that Colo or connected via MPLS to remote offices. The problematic VLAN is always the same remote office data VLAN. Access for clients to each VLAN is set by DHCP and classless routes.
What I find, is that there will be a static route in the RRAAS server's routing table, for the network in question, with a gateway of one of the clients connected to the VPN. A simple route delete statement works and resolves the issue.... For a while.
One interesting thing - the IP that injects itself into the routing table always belongs to one of two different end users. The only thing I can say about those - they are both running Win8.1 Pro and use Hyper-V and have a vSwitch adapter. Both use the native Windows Networking for the VPN connection.