Comment # 5 on bug 1202658 from Ralf Habacker

(In reply to Marius Tomaschewski from comment #4)
> The host _may_ receive something from DHCP server (at a random point of
> time compared to apply time of the static settings) _or_ _not_ and it
> _may_ (accidentially) provide also an IP address from a network that
> matches the gateway from the static setup _or_ _not_.

So you are saying that internally it is not ensured that locally defined static
routes are applied only after the full configuration is received from the dhcp
server ? 

> Because the static settings (static "lease") in ifroute files and
> the dhcp lease are two different leases "config sets" and applied
> independently of each other -- without conditions or dependencies
> between them. 

This answers my question above

> Both capable to provide the complete configuration
> and both need to be complete by themself.

Can an option be added to ensure that static routes are applied after receiving
configuration from dhcp ? 

> The clean way is to fix the dhcp server config to provide the
> routes as described in bug 907495 to provide all routes via
> dhcp (e.g. classless routes option).

Sorry, but this is not an option in our case, because every time the route is
adjusted, the network would have to be restarted and clients would lose
connections.

The usual procedure in this case is:
1. activate the route manually with ip route 
2. add the new route to /etc/sysconfig/network/routes or
/etc/sysconfig/network/ifroute-<dev so it will be set automatically on the next
reboot.