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Nextiva Networking Guidelines

The ideal network involves your Internet Service Provider (ISP) connecting onsite to a stand-alone modem that connects to a router (preferably a router sent to you from Nextiva preloaded with custom Tomato firmware for QoS).  If you have more devices on your network than ports on your router then you can connect a switch to your router to expand the number of ports. 

Issues Involving Double NAT

You must have only one router on your network. Routers preform NAT to allow for multiple computers/devices in your network to connect to the internet. When you connect two routers to your network, in series, you can cause a double NAT which may cause issues with your phones working.

How do you know if you have more than one device performing NAT?

Routers are the only devices that preform NAT and so you just have to make sure that you only have one router. It may be the case that your ISP will sell or provide you with a gateway device that is a modem/router combo device. This device may work fine with Nextiva but you cannot connect another router to it. This will cause a double NAT. 

Issues Involving Firewalls

Firewalls are primarily designed to keep unauthorized traffic from accessing your private network.  In some cases the default firewall rules might cause Nextiva’s traffic to be blocked. The simplest way to avoid issues is to open up inbound and outbound traffic to/from our IP addresses.

How do you ensure your firewall is not blocking Nextiva’s traffic?

Nextiva offers two different platforms and the simplest way to open up connections is to allow all traffic to and from This range covers the IP addresses from – If you are not able to open up traffic to this full range of IP's but can open up traffic to individual IP's then you can allow all traffic to the IP's and Those are the IP addresses phones connect to when they try to place calls. 

If you have any questions directly ask an Amazing Service Team member here or email us at

Related articles: What is Tomato Firmware / QoS? What is Double NAT?

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