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is possible for internal phones to call the external phones that are registered with the
gatekeeper.
Example 6.9. H.323 with Gatekeeper and two D-Link Firewalls
This scenario is quite similar to scenario 3, with the difference that the D-Link Firewall is protecting the "external"
phones. The D-Link Firewall with the Gatekeeper connected to the DMZ should be configured exactly as in
scenario 3. The other D-Link Firewall should be configured as below. The rules need to be added to the rule
listings, and it should be make sure there are no rules disallowing or allowing the same kind of ports/traffic before
these rules.
Web Interface
1. Go to Rules > IP Rules > Add > IPRule
2. Now enter:
• Name: H323Out
• Action: NAT
• Service: H323-Gatekeeper
• Source Interface: lan
• Destination Interface: any
• Source Network: lannet
• Destination Network: 0.0.0.0/0 (all-nets)
• Comment: Allow outgoing communication with a gatekeeper
3. Click OK
Note
There is no need to specify a specific rule for outgoing calls. NetDefendOS monitors
the communication between "external" phones and the Gatekeeper to make sure that it
is possible for internal phones to call the external phones that are registered with the
gatekeeper.
6.2.8. The H.323 ALG Chapter 6. Security Mechanisms
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