Possible to have PPPoE and separate static IP address on same NIC?

Question

Greetings,

For various reasons, my connection to the internet looks like this:

[DSL Modem in Bridge Mode] <-ethernet-> (eth0)[Linux system](eth1) <-ethernet-> [Wireless Router]

(Where the Linux system is running PPPoE, BIND, DHCP, etc.)

In order to diagnose a recent problem, I needed to connect to the web interface on the DSL modem. In order to do this I have to connect from a specific address range and as I am running PPPoE on eth0, I haven't assigned an address to it nor even turn it on. (The modem's web interface is at a fixed IP address regardless of what mode the modem is in and only answers to traffic from a fixed address range)

So anyway, to connect to the modem, and not finding anything helpful on the internet, I just tried assigning an IP address to eth0 after already starting PPPoE (like this: ifconfig eth0 192.168.1.5 netmask 255.255.255.0 up). I didn't really think that it would actually work. But it did. I.e. PPPoE and a static address assigned to eth0 at the same time and both worked correctly. Thus my question.. Should it? Is it safe to do this long-term or am I just lucky that it works long enough for me to get that which I need to done?

Thanks!

Answer 1

It's fine. PPPoE and IP are carried in Ethernet frames of different types.