Troubleshooting
Problem
Communication might fail when traffic is destined to an IP which has other network interfaces on the same subnet.
Also, an interface might not be able to connect out side of the local subnet, through the gateway.
Cause
If there are two (or more) interfaces configured on the same subnet, for example:
eth0: 192.168.0.10/24
eth1: 192.168.0.11/24
The DataPower firmware's eth0 interface might see the 192.168.0.11 traffic and try to handle or act as if it was eth1.
eth1: 192.168.0.11/24
The DataPower firmware's eth0 interface might see the 192.168.0.11 traffic and try to handle or act as if it was eth1.
Diagnosing The Problem
One of the interfaces might NOT be able to reach out through the gateway, which results in broken or partial traffic. Often the RX traffic seen by the "bad" interface can be significantly lower.
You might also see pings to the "bad" second interface address fails when done from the local switch.
Other environmental factors can alter the behavior a bit, but ultimately one interface might not be able to reach outside of the local subnet and inbound traffic can behave in unexpected ways.
Resolving The Problem
Never use multiple interfaces on the same subnet.
Document Location
Worldwide
[{"Type":"MASTER","Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SS9H2Y","label":"IBM DataPower Gateway"},"ARM Category":[{"code":"a8m50000000CdnuAAC","label":"DataPower->Network (NT)"}],"ARM Case Number":"TS005972231","Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"All Versions"}]
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Document Information
Modified date:
13 July 2021
UID
ibm16466713