Home / server / Questions / 580077
In Process
stighy
Asked: 2014-03-06 11:06:32 +0800 CST

What is the Linux command to get the current PPTP ip address?

  • 772

I have a Linux script that allows me to route some traffic through a VPN interface, and other traffic (from different IP) through another interface. This is my script: 

echo "ip route del default via 192.168.120.10 dev ppp0;" >> /tmp/firewallscript.sh
echo "ip route add default via 192.168.1.254 dev eth0;" >> /tmp/firewallscript.sh
echo "ip route add table 55 default via 192.168.120.10 dev ppp0;" >> /tmp/firewallscript.sh
echo "iptables -t mangle -I PREROUTING 1 -s 192.168.1.40 -j MARK --set-mark 55;" >> /tmp/firewallscript.sh
echo "iptables -t mangle -I PREROUTING 1 -s 192.168.1.41 -j MARK --set-mark 55;" >> /tmp/firewallscript.sh
echo "iptables -t mangle -I PREROUTING 1 -s 192.168.1.42 -j MARK --set-mark 55;" >> /tmp/firewallscript.sh
echo "ip rule add fwmark 55 table 55;" >> /tmp/firewallscript.sh

Because my VPN's IP changes a lot, I would like to 'parametrize' it. So instead of write this line code:

echo "ip route del default via 192.168.120.10 dev ppp0;" >> /tmp/firewallscript.sh

I need to write something like: 

echo "ip route del default via @MyVariableIP dev ppp0;" >> /tmp/firewallscript.sh

In which @MyVariableIP is ppp0's IP address. So my questions are:

  1. How can I get interface IP address using bash, knowing that the interface is ppp0?
  2. How to modify the previous script?

Thanks

networking

1 Answers

    1. At the end of this script you can get ip of ppp0 in $ip_of_ppp0 variable

    2. Put this script before yours and replace @MyVariableIP with $ip_of_ppp0 

      n=`ifconfig|grep -B10 'POINTOPOINT' | cut -d " " -f1 `
m=`ifconfig|grep -B8 'POINTOPOINT'|cut -d " " -f12|grep 'addr:1'|cut -d ":" -f2 `
f=`echo $n`
l=`echo $m`
arr=($f)
amm=($l)
h=0
for i in "${arr[@]}"; do              
        ip=${amm[$h]}
        h=`expr $h+1`
        if [[ "$i" = "ppp0" ]]; then
                ip_of_ppp0=$ip;
        fi    
done
echo $ip_of_ppp0;
    • 0