network problem

[Gerhard Magnus]

I have a small home LAN that I am starting to upgrade from FC9 to FC10.
As the network is still "hardwired" with ethernet cable and the boxes
all have static IP addresses I would like to continue using the old
network service rather than NetworkManager.

After installing FC10 on one of the machines without problems, I stopped
and disabled NetworkManager and configured the network using the widget
System -> Administration -> Network from the gnome desktop and filling
in the "DNS" and "Hosts" information as with FC9. But then I made a typo
in editing device etho under the "Devices" tab -- I accidentally typed
in the gateway address instead of 255.255.255.0 in the "Subnet mask"
field. Now whenever I try correcting this from the "network" widget the
field reverts back to what I mistakenly typed in before. This is
apparently why I can't reach the network from this box.

Is there an easy fix to this -- short of doing the installation over?
Thanks for the help!

Jerry