The drivers for the network cards in PowerEdge generation 11 servers ( r510, r610, r710, etc) are not included by default with the Debian installer.
More specifically, the Broadcom cards will have issues. You can check the output of lspci to see if you have these cards. Like so:
root@server:~# lspci | grep Broadcom
01:00.0 Ethernet controller: Broadcom Limited NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
01:00.1 Ethernet controller: Broadcom Limited NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
If your server is already installed and physically available, grab a USB and do the following steps:
Download the required drivers from:
Just change stretch to what ever version you’re running.
Move the .deb file into the USB, and plug it into the server.
Install the .deb file:
dpkg -i firmware-bnx2_20161130-3_all.deb
Next, verify that the the installation was successful:
root@server:~# lsmod | grep bnx
bnx2 86016 0
Finally, load it:
root@server:~# modprobe bnx2
You should now be able to bring the network device up and either receive an IP via DHCP or configure one manually.
You may also want to reboot your server at this point to ensure everything gets loaded properly at system start up