21.4 Exchange of routing information
Figure 21.11 Common traffic rules for VPN tunnel
21.4 Exchange of routing information
An automatic exchange of routing information (i.e. of data informing about routes to local subnets) is performed between endpoints of any VPN tunnel (or between the VPN server and a VPN client). thus, routing tables at both sides of the tunnel are still kept updated.
Routing configuration options
Under usual circumstances, it is not necessary to define any custom routes — particular routes will be added to the routing tables automatically when configuration is changed at any side of the tunnel (or at the VPN server). However, if a routing table at any side of the VPN tunnel includes invalid routes (e.g. specified by the administrator), these routes are also interchanged. This might make traffic with some remote subnets impossible and overload VPN tunnel by too many control messages.
A similar problem may occur in case of a VPN client connecting to the WinRoute’s VPN server.
To avoid the problems just described, it is possible to go to the VPN tunnel definition dialog (see chapter 21.3) or to the VPN server settings dialog (refer to chapter 21.1) to set which routing data will be used and define custom routes.
Kerio VPN uses the following methods to pass routing information:
•Routes provided automatically by the remote endpoint (set as default) — routes to remote networks are set automatically with respect to the information provided by the remote endpoint. If this option is selected, no additional settings are necessary unless problems regarding invalid routes occur (see above).
•Both automatically provided and custom routes — routes provided automatically are complemented by custom routes defined at the local endpoint. In case of any colli-
