F5 is upgrading its customer support chat feature on My.F5.com. Chat support will be unavailable from 6am-10am PST on 1/20/26. Refer to K000159584 for details.

Forum Discussion

Coso_17543's avatar
Coso_17543
Icon for Nimbostratus rankNimbostratus
Mar 14, 2011

BigIp source addresses

hi all,     I don't know if this is an easy question but it's a bit urgent for me.     We need to balance 2 servers under a VIP for some services, telnet and FTP included.     The po...
application delivery
dev
devops
iRules
Michael_Yates's avatar
Michael_Yates
Icon for Nimbostratus rankNimbostratus
Mar 15, 2011
If the destination (application servers / pool member servers) are configured on a subnet "owned" by the BigIP's then you can disable SNAT. Ownership can be defined as the F5 / BigIP being the default gateway for the Subnet (making it the default gateway for the server through subnet ownership).

 

 

If SNAT Automap is disabled then the destination servers will recieve the Client IP Address (client IP Address in this case being the source IP Address of whatever is accessing the Virtual Server on the F5 (making the Client IP Address a relative term)). The return traffic back to the client from the server will go through the BigIP back to the client because the BigIP is its default gateway (preventing a broken network route).

 

 

If the servers are on a different subnet not owned by the BigIP, then you will have a communication failure due to a broken route.

 

 

The BigIP will NOT auto detect and SNAT automatically without some type of logic in an iRule.

 

 

Does this make more sense?