D-Link DSR-250N User Manual page 71

Unified Services Router
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This router supports multi-NAT and so the External IP address does not necessarily
have to be the WAN addr ess. On a single WAN interface, multiple public IP
addresses are supported. If your ISP assigns you more than one public IP address,
one of these can be used as your primary IP address on the WAN port, and the
others can be assigned to servers on the LAN or DMZ. In this way the LAN/DMZ
server can be accessed from the internet by its aliased public IP address.
7.
Outbound rules can use Source NAT (SNAT) in order to map (bind) all LAN/DMZ traffic
matching the rule parameters to a specific WAN interface or external IP address (usually
provided by your ISP).
Once the new or modified rule parameters are saved, it appears in the master list of
firewall rules. To enable or disable a rule, click the checkbox next to the rule in the
list of firewall rules and choose Enable or Disable.
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The router applies firewall rules in the order listed. As a general rule, you should
move the strictest rules (those with the most specific services or addresses) to the
top of the list. To reorder rules, click the checkbox next to a rule and click up or
down.
External IP address: The rule can be bound to a specific WAN interface
by selecting either the primary WAN or configurable port WAN as the
source IP address for incoming traffic.
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User Manual