(Note: this is a separate but related issue to bug 1250705, which applies to the kernel.)

Please update from NetworkManager 1.0.0 to NetworkManager 1.0.4 in RHEL 7, to fix behavior that causes a standalone corporate VPN client to regularly disconnect when operating over a DHCP-enabled NetworkManager connection. (This does not occur with NetworkManager prior to 1.0, i.e., in RHEL 6.)

When the VPN client is started, it installs its own additional routes with a lower metric than existing routes to ensure that all traffic goes through the tunnel interface it creates. To enforce this, the VPN client monitors netlink for routing changes and disconnects immediately if any occur. When the DHCP lease on the NetworkManager connection is renewed and the address lifetime is updated, NetworkManager calls nm_platform_ip4_route_sync() and attempts to restore the routing table to its earlier state prior to starting the VPN client.

This is resolved in NetworkManager 1.0.4, which now attempts to preserve IP confiugration changes that are made outside of NetworkManager. From my examination of the code, this appears to have required substantial changes and so the minor version upgrade of NetworkManager is likely necessary to incorporate these into RHEL 7.