There was an update to my Fedora 17 Linux and among others, I got a new kernel. I didn't notice it at the time, but the reboot ate one of my Ethernet interfaces. There are two NICs on the motherboard, but on top of those, I have an Intel multi-port NIC. So in the end, there are more than your usual dose of ports.
Traffic to one particular LAN didn't function and I started to investigate:
# ifconfig -a
...
rename5: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 90:e2:ba:1d:33:f1 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device memory 0xfe7e0000-fe800000
Well... I don't remember which one of my Ethernet-ports was rename5 after installation. Typically they are something like eth0, eth1 and so forth. Modern Linuxes tend to add more complexity with names like p2p2 or so, but I've never seen rename5-type naming.
From that I concluded that udev goofed up something. Fedora 17 does not create the /etc/udev/rules.d/70-persistent-net.rules-file which would solve my problem. Lot of Googling later, I found this page, it contains very useful Perl-script to dig enough system information and report it in udev-compatible format, in my case it yields:
# perl /root/bin/write_udev
...
# Added by 'write_udev' for detected device 'rename5'.
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="90:e2:ba:1d:33:f1", NAME="rename5"
I created the persistent rule -file and added above into it. I just edited the NAME-part and renamed the interface properly.
Getting the rules to take effect was bit tricky. None of these worked:
udevadm trigger
udevadm control --reload-rules
udevadm trigger --attr-match=address='90:e2:ba:1d:33:f1'
udevadm trigger --sysname rename5
The trick was to get the full path with udevadm trigger --verbose --sysname rename5 -command and use the test-command with the full path:
udevadm test --action=add /sys/devices/pci0000:00/0000:00:06.0/0000:02:00.1/net/rename5
Then I got my new rule to take effect immediately and my interface up and working.
