On 03/27/2017 08:47 PM, L A Walsh wrote:
James Knott wrote:
Pinging out is one thing, but I don't ever recall seeing a router that could forward incoming ICMP through NAT.
--- Note, that you are receiving an "incoming ICMP" when you get back a ping answer, but the incoming traffic is seen as related to your outward ping and can be routed back to the source (behind a router).
The reason it is "impossible" to get a ping from outside their router -- for most people, is because inside their routers there are no "permanent" IP addresses, only "private" or "non-routable" IP ranges (192.168.x.y or 10.x.y.z or similar).
So no one on the outside would be able to send a ping to a host behind their router, as their local IP addresses are unknown on the outside of the router.
If you have a fixed ipaddr behind a firewall or modem that is associated with a DNS sitename, then someone on the outside can ping that addr from the outside (and get a response if the device is configured to respond to pings). For example, I think my linux server is pingable @ ishtar(dot)tlinx(dot)org.
Quite so and I can do that on IPv6 for all IPv6 capable devices on my network. That's why I said "through NAT" in my reply. On IPv6, I have a /56 prefix, but on IPv4, I have only a single public address & NAT, so I can't ping anything behind my firewall on IPv4. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org