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Forum Discussion

ganaps_283043's avatar
ganaps_283043
Icon for Nimbostratus rankNimbostratus
May 10, 2017

Automap configuration

we had an issue with one of our MQ channel status which is failing every 15 minutes. Four of the MQ servers are behind the VIP and did not help even after the server reboots. As a final option we con...
application delivery
BIG-IP
LTM
Jad_Tabbara__J1's avatar
Jad_Tabbara__J1
Icon for Cirrostratus rankCirrostratus
May 11, 2017

Hello Ganaps,

 

The AUTOMAP setting will replace the source IP address of the request. Precisely, it will modify "client IP addr" by the "BIG IP's Self IP addr".

 

This allows backend servers (pool members) to respond directly to BIG-IP's self IP address. In this manner, both requests & responses pass through the BIG-IP.

 

WITHOUT automap, if it is not explicitly configured on backend server or on routers, responses traffic will respond to the "client IP addr" which will cause asymmetric routing and client will deny traffic because request socket and response socket are not the same.

 

As said before, it is possible to set the "Source Address Translation" to "none", in this case you need to be sure that backend servers are configured to route responses to BIG IP's self IP addr.

 

If you encounter this issue only on this VS (as you said you do not have the problem on other VSs configured with "Automap") you may check if backend servers are on different subnets. In this case maybe you have different rules applied on your routers for these subnets.

 

Regards