NXU-2B Operations Manual
8-3
Interoperability Now!
What happens if two NXU-2Bs have the same IP address (or an NXU-2B has the same
address as some other device)?
Bad things will happen. Well, not bad things, but obviously it will not work properly. Both units
will respond at the same time, causing network errors. The extreme case would be if an NXU-
2B is programmed to have the same IP address as an existing computer on the same network.
This would likely render that computer unusable for network functions, and could cause other
users to have problems as well. The bottom line is that two devices on the same network cannot
share the same IP address.
What is a firewall?
A firewall is a device that prevents people outside of a network from accessing computers of
devices inside the network. It’s a security device. A company firewall prevents incoming
network connections, so no one outside the company can access the company’s computers via
the Internet.
How does a firewall affect the NXU-2B?
A firewall may prevent a connection between two NXU-2Bs if one is behind the firewall and the
other is not. This may occur if the client unit is outside the firewall as the firewall is intended to
prevent connections initiated from outside the firewall.
Should I use a firewall with the NXU-2B?
Strictly speaking from the standpoint of the NXU-2B, there is no reason to use a firewall with
the NXU-2B. The NXU-2B is a stand-alone network device which poses minimal security risks.
However, if the network the NXU-2B is on is shared with computers, servers, or other network
devices, then a firewall may be advisable. Talk to your network administrator about such
situations.
What do I do if my network has a firewall?
If you know (or suspect) the network you are on has a firewall, go ahead and try to connect the
two units. The firewall may already be properly configured. If it is not, then the following things
should be considered.
If a server unit is behind a firewall, then the server unit’s VoIP port needs to be opened on the
firewall for both TCP and UDP. This is called “opening a hole in the firewall” and should only
be done by (or with the cooperation of) the network administrator. This will allow TCP and UDP
packets through the firewall so they can be received by the server unit. There is no security risk
in doing this since the NXU-2B cannot be made to access files or forward information to or from
other systems.
If a client unit is behind a firewall, then nothing needs to be configured on the firewall. Most
firewalls will allow traffic back through them that is related to a connection that was initiated by
a computer on its network.
Summary of Contents for NXU-2B
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Page 18: ...NXU 2B Operations Manual 1 10 End of Section One...
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Page 60: ...NXU 2B Operations Manual 6 8 End of Section Six...
Page 62: ...NXU 2B Operations Manual 7 2 End of Section Seven...
Page 68: ...NXU 2B Operations Manual 8 6 End of Section Eight...