Netgear WPN824 v2 & VOIP/SIP -> Not working!

I have a voip.co.uk account and am on a Telewest broadband connection. I
use a Netgear WPN824 v2 router connected to the cable modem.

I have tried using the X-Lite softphone or an Atcom 168 ATA and with
both, I can place calls using voip.co.uk.

However, with neither can I receive any calls using voip.co.uk. Every
time I try, the router simply re-boots itself and I get a invalid number
message on the phone.

This happens whether I use port forwarding and/or disable the SPI
firewall and NAT. Even using DMZ does not work.

Has anyone got this router to work with VOIP/SIP and if so how?

If not, what other wireless routers with SPI firewall are people using
successfully with VOIP/SIP?

Mark

After serious thinking Mark wrote :
> I have a voip.co.uk account and am on a Telewest broadband connection. I use
> a Netgear WPN824 v2 router connected to the cable modem.
>
> I have tried using the X-Lite softphone or an Atcom 168 ATA and with both, I
> can place calls using voip.co.uk.
>
> However, with neither can I receive any calls using voip.co.uk. Every time I
> try, the router simply re-boots itself and I get a invalid number message on
> the phone.
>
> This happens whether I use port forwarding and/or disable the SPI firewall
> and NAT. Even using DMZ does not work.
>
> Has anyone got this router to work with VOIP/SIP and if so how?
>
> If not, what other wireless routers with SPI firewall are people using
> successfully with VOIP/SIP?
>
> Mark

I've only ever tried with some unbranded wired router with SPI and had
to disable the SPI. It might prove to be a clumsy approach.