Hi,
Just a quick response here about the networking discussion. I'm probably missing something but it seems that the debate is about the basic operation of packet routing in an IP network. I think there may be some confusion about the role of netmask. The function of a netmask is to tell the IP network stack how to distinguish local IP addresses (hosts that are connected to the same local net as my machine) from those IP addresses that are remote (must be routed).
> So basically you're telling me that if I send a packet to 172.13.100.2 on an interface with IP 192.168.20.100, Windows
> will let the "unknown packet" through to the router/firewall ?? Total non sense in my opinion. It's a perfect vehicle for
> network flooding and spoofing.
Assuming that the 192.168.20.100 interface has been configured with a default route set up to a router, then, yes, this is exactly what needs to happen. Otherwise you would never be able to contact any machines other than those on your local network. Note that you don't "send a packet to 172.13.100.2 on an interface with IP 192.168.20.100"... you send a packet to 172.13.100.2. It is the network stack that figures out where it goes based on its connected interfaces and routing table.
When I try to ping "
www.google.com," after the appropriate DNS lookup, I get some IP address (74.125.224.147) which is not directly connected to my local network. The network stack knows this by looping through all my directly connected interfaces and seeing if the network address (IPaddr bitwise_and not netmask) matches the network address for Google's IP. If it does, the message is just sent on the local interface directed at the IP address in question. If it isn't, then it looks first for a route that is specific to this network and then for a default route. For most machines, the default route points to a router on the one network interface. The packet is sent to the router where it will forward it out one of its *other* interfaces on its way to the destination. If at any point the packet cannot be forwarded because of a missing route, a "no route to host" response is returned (if using TCP).
In other words, IP addresses that are not on your local network (as defined by the interface netmask) will get sent to your router for further processing. If this didn't happen, you probably couldn't be reading this message.
So, what I believe the OP is asking is to say, "I want to connect to a specific ArtNet device by IP address and that address is not on my local network. Just let me type in the address of the device." For that matter, a host name resolved through DNS should also be legitimate here. This seems like a reasonable request when dealing with lighting equipment at remote sites.
As an aside, the netmask is also used to determine the broadcast IP address for your local network... (yourIPaddr bitwise_or netmask).
Apologies if this is all terribly remedial and I completely missed the point of your discussion...
Rob
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