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Further to this question, what is the philosophy behind adding an IP to the bridge device br0 and not to eth0 that is a part of the bridge. None of the answers to that question satisfied me.

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possible duplicate of Adding ip address to a bridge interface – Jason Berg Aug 10 '11 at 5:07
It'd be nice if you'd explain why you found those answers unsatisfying (although I admit they're not particularly high-quality). – womble Aug 10 '11 at 5:29
Not satisfying because I read them but still not understand, may be because I am new to Linux network administration – mmonem Aug 10 '11 at 5:31
It would be nice to link me to a page containing graphs or information for newbies – mmonem Aug 10 '11 at 5:32
up vote 4 down vote accepted

The way to think about a Linux bridge is that it consists of two parts:

  • A virtual switch, which you can plug network cables into by attaching a physical NIC; and
  • A "virtual NIC" that is what connects the machine's own network stack to the virtual switch.

Confusingly, they both have the same name.

When you create a bridge and place a physical NIC into the bridge, that physical NIC no longer acts like a NIC, it is, instead, just a network cable (at least, that's the easiest way to think about it). So, since you need to have a NIC to associate an IP address with, you use the "virtual NIC" that's a part of the bridge.

I'd draw some ASCII art, but I suck at that, so you'll just have to visualise it...

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Thanks for the answer. I like your explanation. – mmonem Aug 10 '11 at 6:56

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