[Opensim-dev] IP v6 (was: Hearthbeat lost (LLCircuitData::checkCircuitTimeout))

[Jeff Kelley]

At 11:53 PM +0100 12/12/19, Jeff Kelley wrote:

>traceroute is filtered inside my ISP network,
>however mtr shows no significant packet loss.

Not true. That was a tcp test. The udp test gives 100% packet loss, 
which is no more significant. Usual network tools, like traceroute, 
are useless in this new context.

I won't bother more this list with a specific network issue. That was 
a flag for what seems to me a foreseeable problem.

Here, in Europe, there is no longer IP v4 in core network. v4 is 
dead. All residential traffic is, or will soon be tunneled inside v6. 
The v4 network is less and less transparent, with things such as 
Carrier Grade NAT (CGNAT), port sharing, tunnelling, QoS.

v4 addrresses are split into four, so you may get randomly the 0-16k, 
16k-32k, 32k-48k or 48k-64k port range. This is done stealthily, to 
not trigger public outcry. I mean, it is not a secret but there is no 
advertisement at all. Not a single mail. You wake-up a morning, your 
static public IP is gone with 3/4 of your ports.

Luckily, some ISP offer a 'full-stack' IP on demand. For a while.

Also, it defeats network diagnostic tools that give now erroneous 
information because thay cannot see inside the tunnel.

This is a serious issue for people running a HG standalone at home. 
But it may also hurt ppl simply logging to OSGrid since UDP traffic 
may be broken on the way. That's the tarpit i stumbled in.


-- Jeff