temporary fix [dog tunnel lite]( https://github.com/vzex/dog-tunnel/tree/udpVersion ) reconnect port in used issues, from this post: https://www.v2ex.com/t/362833

dtunnel_systemd.sh

#!/bin/bash
# temporary fix [dog tunnel lite]( https://github.com/vzex/dog-tunnel/tree/udpVersion ) reconnect port in used issues  
# before run this script you need to install `sudo`, `dog-tunnel lite` on server, and install `screen`, `sudo`, `dog-tunnel lite` on client 
#
# you can download `dog-tunnel lite` binary file here ( the offcial prebuilt arm binary file not work for me ):
#   [amd64]: wget https://raw.githubusercontent.com/yangxuan8282/docker-image/master/dog-tunnel/lite_v1.30/amd64/dog-tunnel
#    [arm]:  wget https://raw.githubusercontent.com/yangxuan8282/docker-image/master/dog-tunnel/lite_v1.30/arm/dog-tunnel
# the binary file was built in docker ( https://github.com/yangxuan8282/docker-image/blob/master/dog-tunnel )   
# the default installation path of `dog-tunnel lite` is `/usr/local/bin/`
#
# if you got `Permissions 0644 for '/home/pi/.ssh/id_rsa' are too open.` when ssh into your server, you can fix it by: `chmod 600 ~/.ssh/id_rsa` on client
# and before execuate script you have to edit the value in line 31-38

# echo -n "Type your server ip and press [ENTER]:"
# read $SERVER_IP
# echo -n "Type your server ssh port and press [ENTER]:"
# read $SERVER_SSH_PORT
# echo -n "Type your server username and press [ENTER]:"
# read $SERVER_SSH_USER
# echo -n "Type your server user ssh key path(absolute path) and press [ENTER]:"
# read $SSH_KEY
# echo -n "Type your dog-tunnel port on server and press [ENTER]:"
# read $DTUNNEL_PORT
# echo -n "Type the port you want to forwarding on local host and press [ENTER]:"
# read $LOCAL_PORT
# echo -n "Type the remote port on server and press [ENTER]:"
# read $REMOTE_PORT
# echo -n "Type your xor and press [ENTER]:"
# read $XOR
#LOCAL_USER=who am i | awk '{print $1}'
SERVER_IP=
SERVER_SSH_PORT=
SERVER_SSH_USER=
SSH_KEY=
DTUNNEL_PORT=
LOCAL_PORT=
REMOTE_PORT=
XOR=

#server:

echo "[Unit]
Description=Dog tunnel for http
After=network.target

[Service]
ExecStart=/usr/local/bin/dog-tunnel -service :$DTUNNEL_PORT -v -xor $XOR
Restart=always
RestartSec=60

[Install]
WantedBy=multi-user.target" | ssh -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo tee /etc/systemd/system/dtunnel-server.service"

ssh -f -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo systemctl daemon-reload"
ssh -f -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo systemctl start dtunnel-server"
ssh -f -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo systemctl enable dtunnel-server"

#client:

echo "[Unit]
Description=Dog tunnel for http
After=network.target

[Service]
ExecStart=/usr/local/bin/dtunnel-up.sh
ExecStop=/usr/local/bin/dtunnel-down.sh
Restart=always
RestartSec=60

[Install]
WantedBy=multi-user.target" | sudo tee /etc/systemd/system/http-dtunnel.service

echo "#!/bin/bash
ssh -f -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo systemctl restart dtunnel-server"
/usr/local/bin/dog-tunnel -service $SERVER_IP:$DTUNNEL_PORT -v -action 127.0.0.1:$LOCAL_PORT -encrypt -xor $XOR -local :$REMOTE_PORT -pipe 5 -r
" | sudo tee /usr/local/bin/dtunnel-up.sh

echo "#!/bin/bash
ssh -f -i $SSH_KEY $SERVER_SSH_USER@$SERVER_IP -p $SERVER_SSH_PORT "sudo systemctl stop dtunnel-server"
" | sudo tee /usr/local/bin/dtunnel-down.sh

sudo chmod +x /usr/local/bin/dtunnel-up.sh
sudo chmod +x /usr/local/bin/dtunnel-down.sh

sudo systemctl daemon-reload
sudo systemctl start http-dtunnel
sudo systemctl status http-dtunnel
sudo systemctl enable http-dtunnel

# if you still got connection issues, you can add a cron job to check if website is down, it will check your site with `cURL` every hour
# and will restart the `http-dtunnel-service` if your site is down
# run this command on client: `sudo crontab -e`, and append this line at the end of the file ( remove the # , and replace $URL with your own url ):

# 0 * * * * curl $URL -s -f -m 5 -o /dev/null || systemctl restart http-dtunnel