sipgate basic 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 contains steps that should help resolve problems in most situations. 


Please first try the steps in these Help Articles:

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

 Common errors which can be due to router and/or firewall configuration include:

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


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 router and 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. Only 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.


 Do you have more than one VoIP phone or device registering over the same router?

Please use different Local SIP Port and Local RTP (Media) Port values in the settings of each of your VoIP Phones.

For a Help Guide about local port numbering click here.


 After making changes to your router or phone's port settings test with and without the STUN Server included in the settings of your VoIP phone or device.

Our STUN Server is:

STUN Port: 3478


Port Forwarding:

If you still experience problems after trying the recommendations above, you could try port forwarding.

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/devices.

Your port-forwarding rules should use the UDP Protocol.

With port-forwarding in place please leave UPnP and SIP ALG disabled in your router settings.

After making any changes to your router settings, please again test with and without STUN enabled in your phone's settings.


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

If your phones are behind multiple NATs or routers, please disable UPnP if your routers support it. You'd also need to compensate for the effects of multiple NATs on SIP traffic.

One possible 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 better solution to double-NATs would be to place one of the routers in 'modem' or 'bridge' mode.


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.


- Gigaset:

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:

Please see this Help article about Virgin SuperHubs. 

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

- Linksys:

Setting up Single Port Forwarding on Linksys Routers


Configuring port forwarding on routers with the NETGEAR genie interface

- TP-Link:

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

- Technicolor:

PlusNET Port-Forwarding Guide (TG582n)

Zen Internet Port-Forwarding Guide (TG582)

- TalkTalk:

Setting Up Port-Forwarding.

- EE/Orange:

Port Forwarding with your Bright Box router.

- Asus:

How do you set up Port Forwarding by using ASUSWRT?

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

- Belkin:

Setting up Port Forwarding with a Belkin router.


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