Question & Answer
Question
What is the best practice for configuring a default gateway on a WebSphere DataPower SOA Appliance and does multiple default gateways improve routing?
Cause
IBM WebSphere DataPower SOA Appliances allow you to configure default gateways with each of the four interfaces. If a default gateway is configured for an interface, then a default route is created.
A default route is only used when a known route does not exists for a destination address.
In the case that:
a) Outbound traffic does not match a known route and
b) Multiple default routes are configured
The appliance randomly picks one of the interfaces with a default gateway configured.
This was designed to meet the requirements of having a robust appliance.
The network administrator can choose to configure the device through the network requirement.
When there are multiple default routes, routeA and routeB for instance, the device chooses routeA some times or routeB at other times, which might cause intermittent failure in connecting to other network destinations.
A default route is only used when a known route does not exists for a destination address.
In the case that:
a) Outbound traffic does not match a known route and
b) Multiple default routes are configured
The appliance randomly picks one of the interfaces with a default gateway configured.
This was designed to meet the requirements of having a robust appliance.
The network administrator can choose to configure the device through the network requirement.
When there are multiple default routes, routeA and routeB for instance, the device chooses routeA some times or routeB at other times, which might cause intermittent failure in connecting to other network destinations.
Answer
It is generally recommended to use one default gateway on the appliance and it should be chosen based on network design. To connect with other destinations/subnets outside of the network, then use static routes.
For example, a network administrator could use a single default gateway to connect all internet-based servers and clients, then use a static route to intranet servers, which might include the back-end Application servers.
Using multiple default gateways allows outbound traffic that doesn't match a specific route to have a random chance of using any of these configured default gateways even if the designated networks are different.
On a related subject, should you choose the default gateway on interface eth0 or mgmt?
One of the interfaces is named mgmt only to help you distinguish from others. Since all network interfaces available in a DataPower device are the same, you can use any interface as a management port, and one or more DataPower network interfaces to route network traffic to/from the device. The selection depends on your network design and the relative network port speed in your selection.
For example, a network administrator could use a single default gateway to connect all internet-based servers and clients, then use a static route to intranet servers, which might include the back-end Application servers.
Using multiple default gateways allows outbound traffic that doesn't match a specific route to have a random chance of using any of these configured default gateways even if the designated networks are different.
On a related subject, should you choose the default gateway on interface eth0 or mgmt?
One of the interfaces is named mgmt only to help you distinguish from others. Since all network interfaces available in a DataPower device are the same, you can use any interface as a management port, and one or more DataPower network interfaces to route network traffic to/from the device. The selection depends on your network design and the relative network port speed in your selection.
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Document Information
Modified date:
04 August 2022
UID
swg21320815