WARNING: Belkin F5D8233-4 router
 

Be forewarned that Belkin F5D8233-4 router is NOT SIP friendly.

It blocks UDP traffic as the firewall on the router thinks it's a DoS Flood attack.

This happens even when you put your ATA into the DMZ, which is not what one would expect. You MUST turn the Firewall OFF. There are no other settings.

So, if you want to use an ATA or such with it, be warned that you need to turn the Firewall off.

Here are some confirmations of the situation:

Solution for users of the Belkin Pre N wireless router - Skype Community
Belkin pre-N router and skype problems.... - Skype Community

Thanks,
RDP

I've seen this myself with its pre-N router. There is an 'extra' firewall by default enabled in the router settings, which needs to be disabled for normal ATA/STUN/NAT settings to work.

Don't worry about it actually disabling your NAT firewall protection; it won't. It is merely disabling the aggressive 'intelligent' pro-active component to the router that is messing up all our usual STUN and NAT compensating settings we use with SIP. You can be without that Belkin-specific stuff (which seems to only cause problems) and have a great internet experience and still be fully protected from the dangers of the open internet.

But i guess only when used with Voxalot, using a VoIP provider directly, isn't a issue ?