Specifications

MBG Engineering Guidelines, Release 8.0

An enterprise can take advantage of the DSL, authenticated DHCP and PPPoE/PPPoA

capabilities of the MSL

server. MSL additionally provides NAT for all devices at the enterprise, a stateful packet filter firewall, and

optional port-forwarding.

Note: If desired and if hardware is available, a third interface may be configured in MSL. This interface might be

useful as a dedicated interface for clustering if a network between the MBG servers can be set aside for this

purpose.

Alternatively, the third interface could be put into bridged mode on MSL 9.2+ to permit an MBG server in parallel

with an existing firewall to transparently handle all traffic from that firewall and accomplish traffic shaping. See

Traffic Shaping for full details.

Additional Local Networks

Additional internal networks or subnets that require access to the Mitel Border Gateway can be added via the

Local Networks panel of the server manager. This access can be limited to individual hosts, or large network

blocks can be used. In all cases, the Router property should be set to the address of the router on the subnet

attached to the MSL server's internal interface.

For example, to allow access from the single subnet 192.168.12.0/24, you would enter a network of

192.168.12.0 and a mask of 255.255.255.0 in the Local Networks panel, plus the address of the router on the

local subnet through which this network can be reached.

If the customer’s network has multiple subnets with a common prefix, access can be allowed from the prefix. For

example, if the customer uses various subnets within the 192.168.0.0/16 network, enter a network of

192.168.0.0 and mask of 255.255.0.0 in the Local Networks panel, and allow the local router to determine the

routing to the individual subnets.

1 Limited support is provided for PPoA. Mitel recommends the use of a D-Link DSL 300T modem at the enterprise site if PPPoA connectivity

is required in gateway mode. Configure the modem to provide DHCP on the internal interface, and use DHCP on the MSL server to configure

the public interface. The modem acts as a bridge. Note that PPPoA routers that provide NAT will not work here.

Figure 2: MBG as Internet Gateway (no enterprise firewall)