[44net] No RX-packets receiving

Hello, Maybe someone can help me with below mentioned problem: I am starting amprnet net with that ampr-ripd using a script bellow #! /bin/bash # dotun.sh script written by N1URO on June, 2013 AMPRIP='44.177.10.10' IPMASK='255.255.255.255' HOST="medvidek.ddns.net" COMMIP=`host $HOST 2>/dev/null | head -n 1 | awk '{print $4}'` AMPRSERVER='169.228.34.84' echo $COMMIP modprobe ipip echo "1" > /proc/sys/net/ipv4/ip_forward ifconfig tunl0 $AMPRIP netmask $IPMASK ip tunnel change ttl 64 mode ipip tunl0 ip link set dev tunl0 up ifconfig tunl0 multicast /usr/sbin/ampr-ripd -t 1 -a $COMMIP -i tunl0 -p pLaInTeXtpAsSwD -f wlan0 -v -s -r ip route add default via $AMPRSERVER dev tunl0 onlink table 1 src $AMPRIP ip rule add from 44/8 pref 1 table 1 ip rule add to 44/8 pref 1 table 1 exit 0 And it worked well but now (and sometimes) I cannot receive packets from that AMPRSERVER to my tunl0 device on udp port 520 which is open (see below): root@raspberrypi:/usr/sbin# netstat -lntup | grep 520 udp     1152      0 0.0.0.0:520 0.0.0.0:* 14076/ampr-ripd and: root@raspberrypi:/usr/sbin# ifconfig tunl0 tunl0: flags=4289<UP,RUNNING,NOARP,MULTICAST>  mtu 1480 inet 44.177.10.10  netmask 255.255.255.255 tunnel   txqueuelen 0  (IPIP Tunnel) RX packets 0  bytes 0 (0.0 B) RX errors 0  dropped 0  overruns 0  frame 0 TX packets 35280  bytes 9295234 (8.8 MiB) TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0 Port 520 is also opened in net router and using: # tcpdump -i wlan0 port 520 I cannot see amprnet sevrver response. TKS/73 Libor,  sysop of node OK2PEN-5