SNAT Scenario: Real server cannot communicate with the Internet without Virtual Service to Real Server mapping

Real server cannot communicate with the Internet without Virtual Service (VIP) to Real Server mapping (RS).

Product: LoadMaster

Version: Any

Platform: Any

Application: Any

• Unless there is some VIP:DummyPort-to-RS:DummyPort mapping on the LoadMaster, that real server cannot communicate with the Internet.
• If there is a RS mapped to a VIP on the LoadMaster however, then that real server can successfully communicate out to the internet.

• Enable SNAT on LoadMaster.
• Set the default gateway of a real server to be the loadmaster.
• Add that server to a virtual service on the loadmaster, and run a TCP Dump.
• Try to reach the internet on that real server and it should be successful.
• A TCP Dump should show outbound requests to several public internet IPs, sourcing from either the LM interface, or the VIP that real server resides on (Depending on the specific SNAT setting enabled).
• Remove that real server from the VIP, and try to reach the internet again, and it should fail.

• Either a real server is required to be added to a VIP on the LoadMaster in order for outbound internet access to be possible, OR Packet Routing filtering needs to be DISABLED on the LoadMaster.
• In order to disable Packet Routing Filtering, Global Balancing (GSLB) must first be disabled. 
• GSLB can be disabled under Global Balancing > Disable GSLB.

• Packet routing filtering can then be disabled under Packet Routing Filter option within System Configuration > Network Setup > Packet Routing Filter 

• With the packet routing filter disabled, any server with the loadmaster configured as its network default gateway should now be able to communicate out to the internet.