[Server-devel] xs-config 4.1 - F9 networking is all go

[Martin Langhoff]

Just added a README.networking that oulines how things work and how to
apply local configuration that does not break on upgrades...

Overview
========

Network configuration on the XS follows an IP numbering and
routing scheme outlined in

   http://wiki.laptop.org/go/XS_Configuration_Management

So the IP addresses, netmasks and routes for all the LAN and
mesh WLANs are defined by the 'server number' (the 'role' of
the server).

To assign a server role, run

   # this script updates /etc/sysconfig/xs_server_number
   # and writes to STDOUT the rest of the configuration
   /etc/sysconfig/olpc-scripts/network_config N >
/etc/sysconfig/xs_network_config

   # update any config files that integrate network config

   cd /etc
   make -f xs-config networkset

   # and
   /etc/init.d/network restart

In some cases you may need to restart for the update to
completely take effect.


Configuring the Internet/WAN connection
===================================

If your internet connection is on eth0 and you want to set
a static address, create a file called

   /etc/sysconfig/network-scripts/ifcfg-eth0-local

- and it will override the defaults provided. You have a
template for that file in

   /usr/share/doc/xs-config-*/ifcfg-eth0-local.example


How configuration is managed
============================

All the /etc/sysconfig/network-scripts/ifcfg-<device> files read
values from /etc/sysconfig/xs_network_config and configure the
device according to the role.

If you want to override this, edit /etc/sysconfig/network-scripts/ifcfg-<device>
-- updates will respect your local configurations (but you will need to review
and integrate changes to the distributed files).


Firewalling
===========

If you want to override the firewall rules, you will want to
review /etc/sysconfig/iptables-config.in which decides which
rules to load, and the rules files in /etc/sysconfig/olpc-scripts

NOTE: Firewall rules are only loaded for server number 1 -
other servers are not exposed to the internet.


Which network device is which?
==============================

If you have 2 NICs, the installer will have decided which one is eth0
and which one
is eth1 based on which one is seen by the kernel first. In other
words, pretty much
random.

If they are different brand / type of cards, you can see which one is
which doing

   cat /etc/udev/rules.d/70-persistent-net.rules

If they are not set the way you want them, you can use the provided
`xs-swapnic`
script which will immediately (and silently!) swap them over. Reboot
for it to take effect.


If you only have one NIC
========================

It will by default be set to be eth0 (the WAN connection). This is the
recommended
configuration. However, if you want to have that only NIC as your LAN
connection,
use the xs-swapnic utility which will set it to be eth1. Reboot for it
to take effect.

-- 
 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff - working code first
 - http://wiki.laptop.org/go/User:Martinlanghoff