ifcfg-rh: error: Missing or invalid IP4 gateway address '0'

The dreaded message ifcfg-rh: error: Missing or invalid IP4 gateway address '0' perplexed me last time when I let NetworkManager bring up ethernet interfaces. Everything worked fine before, but with NM one of the network cards wasn't been configured. I've read ifcfg-ep0 hundred times, checked /etc/sysconfig/network, /etc/default-routes, other interfaces configuration but still cannot find this gateway address of ‘0’.

Then I've found it: I had per device routes configured in /etc/sysconfig/network-scripts/route-ep0. I had it slightly wrong, with ADDRESS0= and NETMASK=0 provided but GATEWAY0 missing. So, if you encounter such message, check if you per device-route config file contain GATEWAYx= or GATEWAYDEVx=0.

After correcting this issue NM was able to bring up interfaces just like /etc/init.d/network.

Re-enabling NetworkManager was prompted by systemd migration of my home server. Traditional network.service has some annoying bugs when systemd is used. NM – has not.

Also, I've converted few services to native units. For now: maradns, aiccu, spamassassin. Seldom used mounts like /boot benefit from dead-easy automount setup. I was able to trim my system's boot time by minute and half. Now it only takes 3½ minutes to start. One full minute is spent in BIOS and harddrives enumeration, there's not way to make it faster. But rest of boot still can be optimized. I'm going to analyze bootchart made during next boot (maybe in few weeks time). Before systemd, my server needed almost 5 and a half minute to boot to GDM screen.