Traffic from and to one Host (or Network) over a specific Alias WAN IP

Question

Hi, 
 we have a /28 public subnet. One IP is the default WAN IP, the others are added as Alias to the Interface. 
 
 How can I make a rule that every outgoing traffic from a specific host or network is going out over one specific of these alias IPs? 
 
 I've seen a few threads with a similar topics, but I've not seen a real solution. 
 
 Greets 
 Daniel

FormerMember · Answer

Just adding on what rfcat_vk said. 
 You need to create an IP host of an Alias IP address and assign it under Translated source (SNAT) in the NAT rule. 
 You may either create a NAT rule with required source networks or can also create a lined NAT in firewall rule and apply SNAT.