Wie Dyndns überwachen, Fritzbox hinter Fritzbox

#!/bin/sh
# DynDNS-Check mit Remote-Reconnect 
# required binaries: cat cut echo grep ping sed sleep telnet wget 


rebootZielbox="no"  # yes/no
ZielboxIP="192.168.178.1"
ZugangsPW="Zielbox_password"
DynDNS="xyz.dyndns.org"

n=7 # Anzahl der Versuche die Telnet-Befehle abzusetzen
t=30 # Wartezeit zwischen den Versuchen in sek.


CHECKIPURL="http://checkip.dyndns.org/"
CHECKIPURL2="http://www.myip.ch/"
# get DynDNS hosts IP
function get_IPs() {
    HOSTIP=$(ping -c1 "$DynDNS" | sed -n 1p | sed -e 's/(//g' -e 's/)//g' | cut -d ' ' -f3)
    wget -q -O /tmp/_current_ip $CHECKIPURL
    CURRENTIP=$(cat /tmp/_current_ip | cut -d ' ' -f 6 | cut -d '<' -f 1)
    if [ -z "$CURRENTIP" -o "$CURRENTIP" = " *" -o "$CURRENTIP" = "*1.0 *" ]; then
        echo "Hmm... $CHECKIPURL seems to be down?! Using $CHECKIPURL2 insteed"
        wget -q -O /tmp/_current_ip $CHECKIPURL2
        CURRENTIP=$(cat /tmp/_current_ip | grep "IP Address" | cut -d ' ' -f4)
    fi
}

if [ "$(ping -c4 "google.de" | grep -c "seq")" -eq 4 ]; then
    get_IPs
    [ "$HOSTIP" != "$CURRENTIP" ] && echo "$(date) => DSL restart - DynDNS Problem" >>/var/media/ftp/uStor01/logs/all_check.log
    i=1
    while [ $i -le $n ]&&[ "$HOSTIP" != "$CURRENTIP" ]; do
        (
        sleep 3
        echo -e "${ZugangsPW}\r"
        sleep 3
        if [ "$rebootZielbox" = "yes" ]||[ "$rebootZielbox" = "1" ]; then
            echo -e "echo '#!/bin/sh' >/tmp/tempscript\r"
            echo -e "echo 'if [ -z \"\$\(grep \"/usr/sbin/telnetd -l /sbin/ar7login\" /var/flash/debug.cfg\)\" ]; then' >>/tmp/tempscript\r"
            echo -e "echo 'echo \"/usr/sbin/telnetd -l /sbin/ar7login\" >/var/flash/debug.cfg' >>/tmp/tempscript\r"
            echo -e "echo 'fi' >>/tmp/tempscript\r"
            echo -e "sh /tmp/tempscript\r"
            echo -e "reboot\r"
        else
            echo -e "killall dsld\r"
            sleep 10
            echo -e "dsld -i -n\r"
        fi
        sleep 3
        echo -e "exit\r"
        ) | telnet $ZielboxIP
        echo "das war Versuch Nr. $i"
        sleep $t
        get_IPs
        i=$(($i + 1))
    done
fi

exit 0

cd /var/flash
cat debug.cfg