Using Private Ipv4 Addresses - D-Link NetDefendOS User Manual

• Destination Interface: lan
• Destination Network: lannet
• Service: my_h323_service
• Comment: Allow incoming H.323 calls.
3. Click OK
Example 6.13. Using Private IPv4 Addresses
This scenario consists of two H.323 phones, each one connected behind the NetDefend Firewall
on a network with private IPv4 addresses. In order to place calls on these phones over the
Internet, the following rules need to be added to the rule set in the firewall. Make sure there are
no rules disallowing or allowing the same kind of ports/traffic before these rules.
As we are using private IPs on the phones, incoming traffic need to be SATed as in the example
below. The object ip-phone should be the internal IP of the H.323 phone behind each firewall.
Web Interface
Create a new H.323 ALG object:
1. Go to: Objects > ALG > Add > H.323 ALG
2. Specify a name for the ALG, in this case my_h323_alg
3. Click OK
Create a custom Service object for H.323:
1. Go to: Objects > Services > Add > TCP/UDP
2. Now enter:
• Name: my_h323_service
• Type: TCP
• ALG: my_h323_alg
• Destination port: 1720
3. Click OK
Create the outgoing traffic NAT IP rule:
1. Go to: Policies > Firewalling > Main IP Rules > Add > IP Rule
2. Now enter:
• Name: H323Out
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Chapter 6: Security Mechanisms