Department - New Rock Technologies OM10 User Manual

Name
IPPBX is behind
NAT, and IP phones
register to IP-PBX
via internet

2.4.4 Department

After login, click "Extension > Department" tab to open the configuration interface.
Shanghai New Rock Technologies Inc.
Description
IPPBX is connected to a router that has static public IP address. Set
the public IP address of router.
In this case, the public IP address that the router maps to the OM is
static, so external IP extensions can register to the OM through this
public address. But since the OM is behind the router (NAT), it is
required to enable port mapping for signaling and voice port of the OM
on the router to ensure normal communication by IP extension.
IPPBX is connected to a router that has dynamic assigned public IP
address. Set if DDNS service supplied with the OM is used: fill in the
user name, password and domain name if Yes is selected; fill in the
DDNS domain name if No is selected.
When enterprises are connected to the Internet through ADSL, the public
IP addresses that operators provide are usually dynamic, namely, the
public IP addresses that the router maps to the OM are always changing.
So external IP extensions cannot register to the OM through a static
address. To solve this problem, users are required to assign a domain
name for the OM by applying for DDNS service, then external IP
extensions can register to the OM through this domain name. Also, since
the OM is behind the router (NAT), it is required to enable port mapping
for signaling and voice port of the OM on the router.
IPPBX is behind multi-stage NAT (e.g. There exists a multi-stage
router between the IPPBX and the Internet).
In this case, since there exists a multi-stage router between the OM and
the Internet, and the router controlled by an enterprise is behind NAT,
the communication problem between the OM and external IP extensions
cannot be solved simply by port mapping. Therefore, it is needed to
enable STUN function (STUN protocol provides a way by which it can
get the address and port mapped by NAT, and so replace the private
network address and port in application layer to traverse NAT) for
working with the STUN server in public network to access the OM
behind NAT, ensuring normal communication by external IP extensions.
The OM has three strategies for using STUN service:
1、 Startup: The OM sends STUN request for signaling port to the
STUN server only at application boot;
2、 Periodic: The OM sends STUN request for signaling port to the
STUN server on a periodical basis;
3、 Periodic & RTP: The OM sends STUN request for signaling and
voice ports to the STUN server on a periodical basis.
In this case, it is still needed to fill in DDNS or static NAT address for IP
extension registering to the OM.
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