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I'm coming from networking where a router/switch has a separate interface for management. Therefore I want to understand how this is implemented for servers/virtualized servers.

I have one subnet for management (remote access to the VM via SSH) and another subnet for connecting the server to the service network. Subnet 0 for management Subnet 1 for webserver, ftp-server, syslog-server, radius ...

Is such a separation practical in server environment or is only a single subnet used to connect a server/virtualized server both for management and service access?

In my current setup, I have two bridges configured on the host and on the guest I have two eth-if (eth0 to br0 and eth1 to br1) but this seems to not be sufficient because the guest needs to know which interface has to be used depending on the application.

Maybe I'm totally wrong here and I'm making it too complicated. Any ideas or help would be great.

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If I'm interpreting your question wrong, just let me know and I will edit to suit

What you're suggesting is definitely possible and is in fact easier with virtualised networking than traditional physical stuff (think VLANs in place of separate switches). In your example, you have br0 and br1. I'm going to assume that br0 is your service network and br1 is your management network. In that case, what you have sounds about right.

On your guest, you need two NICs, one connected to br0 (eth0 in your example) and configure applications on your guest (FTPD, syslogd, apache, whatever) to use eth0 (or to bind to eth0's address more accurately). Your guest's other NIC, eth1 should be configured with a static IP of its own, and configure applications like SSH to listen on eth1's address. You have now got the same concept as most network appliances.

Check that on your host you have a physical interface connected to your services network (let's call it net0 for clarity), and add it to the br0 bridge. Connect your host's other physical NIC (let's call it net1) to your management network (if you're using managed switches, that's just a matter of adding the ports to the right VLANs). Add net1 to br1 on the host, and you're good to go.

Coming from networking, I see what you mean, but in server-world it is a bit more manual to achieve the same effect.

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