How to get client IP from out going requests of WSO2 Elastic load balancer (Avoid masking client IP)

Normally when requests pass through load balancers client IP for actual back end server would be load balancers IP. But sometimes actual back end server may need actual client and load balancers (all  load balancers message passed) IPs to tracing message flows. In such cases normally we use  X-Forwarded-For[1]  header. If we need to achieve same using WSO2  elastic load balancer we need to add following configuration to main sequence. Also if header is already present we should append ip by separating ",". We can use this to avoid masking client IP from WSO2 ELB


[1]http://en.wikipedia.org/wiki/X-Forwarded-For 

Add following configuration to main sequence in flow

<filter source="get-property('transport','X-Forwarded-For')" regex=".*">
<then>
<property name="coming-X-Forwarded-For" expression="fn:concat(get-property('transport','X-Forwarded-For'),
', ')" scope="axis2" type="STRING"/>
<property name="clientIP" expression="get-property('axis2','REMOTE_ADDR')"/>
<property name="X-Forwarded-For" expression="fn:concat(get-property('axis2','coming-X-Forwarded-For'),
get-property('clientIP'))" scope="transport" type="STRING"/>
</then>
<else>
<property name="X-Forwarded-For" expression="get-property('axis2','REMOTE_ADDR')" scope="transport" type="STRING"/>
</else>
</filter>