Port forwarding using DDNS

Question

All 
 A new request came in today to enable port forwarding on the Sophos XG unit. We have a new application that will 
 1. Be installed on a separate network within the LAN on a L2 switch( no vlan's present at the moment - all flat /24 network). Our existing LAN will not connect to this application. We have spare LAN network on which this will go. No segregation required on the LAN. 
 2. Remote access to the application from outside the LAN from the internet 
 
 My existing setup: 
 1. FTTC is primary line and broadband line as backup to existing LAN 
 2. FTTC is primary and have spare static ip addresses in the address range allocated to us. 
 3. Spare ports available on XG. So outgoing/incoming connection from the application server L2 switch can be plugged into the spare port on XG. 
 4. I am not sure where i can configure DDNS for this application on the XG so to access from the web 
 5. My idea is to create an alias on the existing FTTC conected XG port and setup an interface for the application to be conected from remote. Do i have to create a separate vlan in the XG for segregation between the LAN and this app. Is port forwarding on the perimeter firewall an accepted IT standard.

Keyur · Accepted Answer

Hi there, Do you want to access the application server hosted behind the LAN on the WAN terminated on the Sophos XG with an existing line or you want to add IP as an alias. For DDNS configuration - https://community.sophos.com/kb/en-us/123126 
 For DNAT - https://community.sophos.com/kb/en-us/122976

lferrara · Answer

Hi itguy318, 
 sorry but your thread is not very clear. If you want to separate the application, create a VLAN layer 2 on the switch and then create the VLAN layer 3 interface on XG. For this VLAN,use a separate IP/mask than the XG LAN ip/mask. 
 You can create alias on XG and configure DDNS under Network > DDNS menu. 
 Regards