help in SNAT AND NAT

Nitass's configuration should work just fine but just so it's clear:

 

 

1) The internal servers will have their source address NATted to the floating Self IP configured on the external VLAN and

 

2) As Mohamed has suggested, the server's default gateway should be the F5's floating Self IP for the internal VLAN.

 

 

Of course, you should also have a default route configured in LTM that directs the server traffic to wherever it needs to go in your network to reach the Internet.