[mdlug] efficient networking script?

[Aaron Kulkis]

Tony Bemus wrote:
> Hello all,
>     I just loaded an old laptop with a firewall distro called IP Fire
> (http://www.ipfire.org/), it is based on IP Cop.  I have set it up with
> a green+red config.  The red interface is a USB NIC(phone) and the green
> is the built in NIC.  When I unplug the USB NIC it looses the red
> interface, as expected.  then later I plug in the USB NIC and the red
> interface is there but doesn't configure the static ip.  If I run
> "./etc/init.d/network restart" then the red interface get the static IP.
> 
> I wrote a script that checks if the interface is there and if there is
> an IP address.  If there is no interface it does nothing,  if there is
> an interface and a IP address it does nothing. but if there is an
> interface and NO IP address then it restarts the network.  
> This allows my wife and I to just plug in the USB NIC (phone) and wait a
> minute and then the Internet starts working,  no commands to run.
> 
> My question: Is this an efficient way to do this?  
> I have fcron running the script every minuet.
> 
> 
> #!/bin/bash
> 
> red=`ifconfig | grep red0 | wc -l`
> if [ "${red}" -gt "0" ]; then
> echo "Red Interface Exists";
> ip=`ifconfig | grep 192.168.1.2 | wc -l`
> if [ "${ip}" -gt "0" ]; then
> echo "IP address Exists";
> else 
> echo "Restarting network";
> sh /etc/init.d/network restart
> fi
> else
> echo "No Red Interface";
> fi
> 

You might want to adapt this script for your
own situation.  I recommend keeping it in /local/bin
(where /local is on its own partition, so that it
is preserved between new installations).


#!/bin/bash
#
# quicknet
#
# quickly set up for networking on specified interface & IP
#
# Date		Who			What/notes
# -----------	-----------------------	------------------------------------
# 26 Feb 2010	Aaron R. Kulkis		Original version
# http://pastebin.com/yX6WSyMz
#
#
# Essence of program:
#   prompt and read INTERFACE
#     ifup $INTERFACE
#     ifconfig
#   prompt and read IP
#     ifconfig $INTERFACE $IP
#     ifconfig
#   prompt and read ROUTER
#     route add $ROUTER $INTERFACE
#     route
#     route add default gw $ROUTER $INTERFACE
#     route
#   ping ROUTER  (confirm connection to router)
#   ping 8.8.8.8 (Google open DNS host, confirms gateway operation))
#   ping www.google.com (confirms DNS operation)
#
#

SELF=`basename $0`

#
#### GET INTERFACE ##################
#

printf "Use which interface ? "
read INTERFACE

printf "execute ifup $INTERFACE ?"
read RESPONSE
case RESPONSE in
	y* | Y* )
	set -x
	ifup $INTERFACE
	ifconfig $INTERFACE
	set +x
	;;
esac


#
#### GET ADDRESS ##################
#

printf "What IP address for $INTERFACE ? "
read IP

printf "\nAttempting to configure $INTERFACE\n"
set -x ; ifconfig $INTERFACE $IP ; set +x

printf "\nPress return key" ; read A
set -x ; ifconfig $INTERFACE  ; set +x

#
#### DEFINE ROUTER ##################
#

printf "What is the name or IP address of the router/gateway? "
read ROUTER

printf "\nspecifying path to router $ROUTER\n"
set -x ; route add $ROUTER $INTERFACE ; set +x

printf "\nPress return key" ; read A
printf "Verifying route added to route table\n"
set -x ; route ; set +x

printf "\ndefining $ROUTER as the gateway.\n"
set -x ; route add default gw $ROUTER $INTERFACE ; set +x

printf "\nPress return key" ; read A
printf "Verify route added to route table\n"
set -x ; route ; set +x

#
#### VERIFY ROUTE COMPLETE ##################
#

printf "Verifing that route table complete:\n"
set -x ; route ; set +x

printf "test local network with 3 pings: "
 set -x; ping -c 3 $ROUTER ; set +x

printf "test routing by pinging Google public DNS servers 3 times each\n"
set -x
 ping -c 3 8.8.8.8
 ping -c 3 8.8.4.4
set +x

printf "Testing DNS functionality:\n pinging www.google.com 3 times\n"
set -x; ping -c 3 www.google.com ; set +x

### END OF SCRIPT


Typical data file
(typical usage: cd /local/bin ; ./quicknet < norm1

----- Data file begins on next line
eth1
y
192.168.1.101

home

----- Data file ends on previous line.


Note that
akulkis at kulkilap:/local/bin>  grep home /etc/hosts
192.168.1.254   2wirerouter     2wire   home

In the data file, replace home with either the
IP address of your router or the symbolic name
for it which you have placed in /etc/hosts.