Re: setting up network

[Kai Hildebrandt <kai.hildebrandt@web.de>]

Hi.

On Sun, 23 Jan 2005 19:07:54 +0000
Pollywog <linux-debian@shadypond.com> wrote:

> On 01/23/2005 06:50 pm, Alan Pope wrote:
> > On Sun, 23 Jan 2005 18:37:02 +0000, Pollywog
> > <linux-debian@shadypond.com> 
> wrote:
> > > I am planning to stay at a hotel which has Internet access but I
> > > know nothing about the IP addresses they use.  I am assuming they
> > > use dhcp. If I know nothing of their network, what is the most
> > > convenient way to get my laptop connected?
> 
> [...]
> 
> > So you currently use static IP addresses?
> 
> Yes, at home I use static addresses.
> 
I use the map-scheme to decide which connection has to be used. If you
have an Internet router at home your laptop can ping on this should
work.

You have to define a mapping in /etc/network/interfaces:

<snip>
mapping eth0
        script /usr/local/sbin/map-scheme
        map HOME eth0-home
        map HOTEL eth0-hotel

iface eth0-home inet static
        address 192.168.1.3
        netmask 255.255.255.0
        network 192.168.1.0
        broadcast 192.168.1.255
        gateway 192.168.1.1
        # dns-* options are implemented by the resolvconf package, if
installed        dns-nameservers 192.168.1.1
        dns-search your-nework.de

iface eth0-hotel inet dhcp
</snip>

And of course the file /usr/local/sbin/map-scheme:

#!/bin/sh
#
# Check whether I am at home or at hotel
#

# your NIC
DEV=eth0

# your ip-address
ADDR=192.168.1.2/24

# ip-address of host to ping on
GATEWAY=192.168.1.1


if [ `id -u` -ne 0 ]; then exit 1; fi

if [ -x /usr/bin/fping ]; then
    PING="/usr/bin/fping"
else
    PING="/bin/ping -c 2"
fi

ip addr add $ADDR dev $DEV >/dev/null 2>&1
ip link set $DEV up        >/dev/null 2>&1

if $PING $GATEWAY >/dev/null 2>&1; then
    IFACE="eth0-home"
else
    IFACE="eth0-hotel"
fi

ip link set $DEV down      >/dev/null 2>&1
ip addr del $ADDR dev $DEV >/dev/null 2>&1

echo $IFACE
# EOF

Probably this is what you want?


Regards
  Kai