Manual Chapter : Connection Recreation

Applies To:

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BIG-IP LTM

  • 16.0.0, 15.1.0, 15.0.1, 15.0.0, 14.1.2, 14.1.0, 14.0.1, 14.0.0, 13.1.3, 13.1.1, 13.1.0
Manual Chapter

Connection Recreation

One interesting thing to consider is the snat setting for the virtual server. Lets say that you have two virtual servers inbound_vs and outbound_vs. Each virtual server has a route which uses a corresponding transport config, inbound_tc and outbound_tc. Calls received by the inbound_vs would be routed to connection created using the settings of inbound_tc. The persistence entry for these calls would contain the inbound_vs as the source transport and the inbound_tc as the destination transport.
Likewise calls received by the outbound_vs would be routed to connections created using the setting of outgound_tc. The persistence entry for these calls would contain the outbound_vs as the source transport and outboind_tc as the destination transport. If a call arrives on a connection created via outbound_tc and a valid persistence entry still exists, it would route to a connection using the outbound_vs transport. If no connection is found, it would create a new outbound connection using the outbound_vs’s parameters.
Therefore, the virtual server SNAT setting should be that of the VLAN it is on. This is opposite from traditional BIG-IP virtual servers.
Lets say that the inbound_vs listens on the external VLAN and the outbound_tc is for creating connections on the external vlan. The inbound_vs’s SNAT settings are what would be used for creating outgoing connections also on the external VLAN. Inbound_vs’s snat setting would never be used for creating connection on the internal VLAN.
In this case, the SNAT settings of the inbound_vs should match the SNAT settings of the outbound_tc. Likewise the SNAT settings of the outbound_vs should match the SNAT settings of the inbound_tc.