[SR-Users] Keeping Registrations alive in IPv6 scenarios

[Olle E. Johansson]

On 27 Feb 2015, at 09:04, Sebastian Damm <damm at sipgate.de> wrote:

> Hi,
> 
> while testing IPv6 with customers, we fell over quite a few cases, where customers aren't reachable on inbound calls most of the time. And digging into this, we found the home router firewall as the cause for those problems.
> 
> Normally, you would think, all the NAT problems cease when switching to IPv6. But actually, right now I don't know how to fix that problem.
> 
> In IPv4 NAT scenarios, we would flag the customer during the registration, and Kamailio would send NAT pings (those 4 bytes of UDP junk) every few seconds to keep the firewall in the NAT router open. And that worked pretty great.
> 
> Now we have IPv6. We don't have NAT. But we still have a home router in front of SIP devices, with a firewall. And this firewall will allow outbound traffic. But after a few seconds it won't allow incoming connections anymore. And the routers I have seen so far don't have a configurable firewall where you could allow inbound traffic from our server.
> 
> Unfortunately, only our load balancer is IPv6, our registrar is still IPv4 only. And the loadbalancer doesn't know anything about registrations and which customer needs an IPv6 keepalive. 
> 
> Does anyone have a hint, how to keep the IPv6 registrations alive? Thanks in advance.
> 

AARGH. Now I see. Thank you. (Disregard earlier e-mail).

In all modern standards, like SIP Outbound, the need to send keep-alives has been pushed to the client. They need to open a network flow and keep it open - UDP or TCP or TCP/TLS.

As we can't trust device developers to stay up to date, we may need IPv6 keepalives. 

/O