sipgate team & trunking Help

Problems Making and Receiving Calls

Problems making and receiving VoIP calls are often caused by local network issues.

This could be due to your internet connection, traffic congestion, a router's operation, or VoIP phone settings. Often these problems can be quickly resolved or avoided. The settings of your VoIP phones, Router and firewall may be adjusted so that you can use sipgate without any problems.


This Help article provides steps that should help easily resolve issues in most situations.This article assumes that you have assigned your phone or extension numbers in your team account settings to the intended Group or User correctly.


If you've Audio or Speech Quality Issues, first please read this Help Article.

Common errors which can be caused by a router and/or firewall include:

  • Your device does not register itself at sipgate (status "offline") or loses the registration after some time again.
  • Phone calls connect, but audio is lost in one or both directions.
  • Even though you've hung up the call, the phone continues to ring.
  • You can receive inbound calls but can't make outbound calls, or vice-versa.
  • You dial a phone number, but don't hear a ringing tone.
  • The call is disconnected after 5 - 30 seconds.


Issues due to your local network and its configuration may appear intermittently and unpredictably, sometimes only showing up after hours or days of problem free operation. You may find that powering your phones off and on may temporarily solve issues.


Make sure your router(s) and VoIP devices are using the manufacturer's most recent firmware versions. Purchase models with ongoing support, from manufacturer's providing regular firmware and security updates. Always check for known issues, before changing internet service providers, routers or VoIP devices.


Disable SIP ALG, if it's implemented by your router. Poorly implemented router

SIP ALGs are a common source of issues with SIP VoIP.

Disable Stateful Packet Inspection, SPI, options in your router settings.


When more than one VoIP phone or device is registering from the same local network (from behind the same router), please use different Local SIP Port and Local RTP (Media) Port values in the settings of each VoIP Phone.

Each SIP phone should use a successive SIP port like: 49160, 49260, 49360, etc (and same for the starting RTP port - 49104, 49204, 49304, etc.)

Please click here for a Help Guide about local port numbering.


Try using a STUN Server in the settings of your VoIP phone or device.

Our STUN Server is:

STUN Port: 3478

The STUN Protocol is intended to help devices communicate from behind a router's NAT. STUN will not work correctly with all NAT setups, and in some cases STUN may resolve some issues only to lead to others.


Avoid the registration of VoIP phones and devices from behind more than one NAT or router.

Where phones are registering from behind more than one NAT or router, please disable UPnP if your routers support it. You'd also need to compensate for the effects of multiple NATs on SIP traffic.

One double-NAT solution would be to setup port-forwarding rules (see below and here). Or, if you're connecting your own router to a modem-router supplied by your ISP, a solution would be to place the ISP supplied router in 'modem mode'.

Port Forwarding:

If you still experience problems after testing with the recommendations above, you could give port forwarding a try.

You should first of all configure your VoIP devices to use static IP addresses.

Next, please port-forward the Local SIP Port and Local RTP (Media) Port range used by each of your VoIP phones and devices. Your port-forwarding rules should use the UDP Protocol.

Please be sure to forward a range of RTP ports (and not only the phone's starting RTP port). Each VoIP call will use an RTP port and an RTCP port. Forwarding RTP ports ranges like 49104 - 49120, 49204 - 49220, 49304 - 49320 should suffice.

With port-forwarding in use, please leave STUN disabled in your VoIP phone settings, with UPnP and SIP ALG disabled in your router settings.


We can only provide general guidance and recommendations about the setup and maintenance of your local network. Your IT administrator, with your ISP's and device manufacturer's support, are best placed to provide in-depth assistance with your local network configuration.


Port Forwarding Guides and Resources: provides port-forwarding guides for many popular routers.



Information on operating Gigaset VoIP telephones with NAT routers

Gigaset VoIP telephones behind various routers with Network Address Translation (NAT)


DrayTek Routers:

General Router FAQ - Port Forwarding

Setting up Port-Redirection (Forwarding)


Fritz!Box: Configuring Static Port Forwarding


Virgin Routers:

How do I set up port forwarding and port triggering on my Virgin Media router?

Some customers will be unable to resovle issues using the advice in this Help Article. In these cases, using the SuperHub in modem-mode and connecting another router to it will be the only reliable solution. Enabling Modem Mode (SuperHubs).


BT Routers:

Port-Forwarding Business Hubs

Port-Forwarding HomeHubs



Setting up Single Port Forwarding on Linksys Routers


Configuring port forwarding on routers with the NETGEAR genie interface


How to open ports on a TP-LINK wireless router.


PlusNET Port-Forwarding Guide (TG582n)

Zen Internet Port-Forwarding Guide (TG582)


Setting Up Port-Forwarding.


Port Forwarding with your Bright Box router.


How do you set up Port Forwarding by using ASUSWRT?

How many port forwarding does an ASUS Router support? (ASUSWRT)


Setting up Port Forwarding with a Belkin router.


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