Uri Dialing And Firewall Traversal; Creating Dns Srv Records; Firewall Traversal - TANDBERG N3 User Manual

TANDBERG Gatekeeper User Manual
Figure 17 IP Configuration Screen

3.9.1 URI Dialing and firewall traversal

If URI dialing is being used in conjunction with firewall traversal, DNSResolutionMode should
only be enabled on the Border Controller. The DNS records should be updated with the
address of the Border Controller as the authoritative Gatekeeper for the enterprise. This
ensures that calls placed using URI dialing enter and leave the enterprise through the Border
Controller, allowing successful traversal of the firewall.
The LocalDomain DomainName should be set on both the Gatekeeper and the Border
Controller. Any Alternates should also have the same LocalDomain Domain Name.

3.9.2 Creating DNS SRV records

URI dialing relies on the presence of SRV Record in the DNS information for the zone. The
SRV record specifies the location of a server for a particular protocol and domain. Its format is
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defined by an Internet standard RFC 2782 as
_Service._Proto.Name TTL Class SRV Priority Weight Port Target
In our case _Service is defined by the H.323 protocol suite to be _h323ls and _Proto is
_udp. Name corresponds to the host part of the H.323 URI.
How you add the SRV record depends on the type of DNS server you are using. Instructions
for setting up two common DNS servers are given in Appendix: Configuring DNS Servers.

3.10 Firewall traversal

When used with a TANDBERG Border Controller, your Gatekeeper can assist you in making
and receiving calls through firewalls and NAT devices.
Install the Gatekeeper on the private side of your firewall and the Border Controller on the
public side.
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http://www.ietf.org/rfc/rfc2782.txt
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