From: Mark Grosberg <XXXXXXXXXXXXXXXXX>
To: spc@conman.org
Subject: Router
Date: Tue, 22 Jan 2013 11:10:49 -0500 (EST)
> To explain your router: You have three actual hardware Ethernet MAC (Media Access Control)s:
> * The WAN (Wide Area Network) (probably eth0)
* Internal (probably eth1)
* WIFI (probably eth2)
The br0 interface is a software bridging between eth1 and eth2. This way your wireless computer is on the same network as your wired computers. But it's not a real physical device but represents packets from either eth1 or eth2 to the IP (Internet Protocol) stack. The multiplexing is done in the driver for that interface.
As for the IP address discrepancy: eth0 does not actually act as your Internet. That's not how DSL (Digital Subscriber Line) from XXXXXXXX works. eth0 uses managed IP's to bring up a PPPoE (Point-to-Point Protocol over Ethernet) session. So ppp0 will likely have your public IP address. Those packets get tunnled within the other set of IP's. That's a guess since I don't have XXXXXXXXX DSL though.
The thing with software, even embedded software these days is that there are so many layers of existing crap (that don't need to be there but skittish managers are loathe to remove things they don't grok) it's amazingly difficult to grasp the whole picture since there is often little rationale behind it.
That actually explains the behavior I'm seeing on the router [1]. So I can monitor the Intarweb traffic on eth0, overall LAN (Local Area Network) traffic on eth1 and the WiFi network via eth2.
Okay then.