D-Link DFL-1600 User Manual page 171

18.2. FTP 151
2. Services
Objects Services Add TCP/UDP Service:
General:
Enter the following:
Name: ftp-inbound
Type: select TCP from the dropdown list.
Destination: 21 (the port the ftp server resides on).
Application Layer Gateway:
ALG: select "ftp-inbound" that has been created.
Then click OK.
3. Rules
– Allow connections to the public IP on port 21 and forward that to the
internal FTP server:
Rules IP Rules Add IP Rule:
General:
Name: SAT-ftp-inbound
Action: SAT
Service: ftp-inbound
Address Filter:
Source Destination
Interface: any core
Network: all-nets ip-ext
(assume the external interface has been defined as "ip-ext")
SAT:
Check Translate the Destination IP Address
To:
New IP Address: ftp-internal.
(Assume this internal IP address of FTP server has been defined in the
Address Book object.)
New Port: 21.
Then click OK.
D-Link Firewalls User's Guide