When I was debugging, I closed the process that occupied port 443 according to the online tutorial which said the wss
service have to use port 443. Then it cause error when accessing file on my server. I have to say I can easily access the file before.
On another computer terminal
telnet xxx.xx.xx.xx 443
Found that port 443 is unreachable.
Find the security group under the list of cloud servers, open the 443 channel in the inbound direction.
Ubuntu comes with a much simpler firewall configuration tool than iptables in its distribution: ufw
apt-get install ufw
Use ufw to open port 443
ufw allow 443
Now port 443 can be talented, but there is nothing under netstat -antp | grep 443
, According to common sense, information containing 0.0.0.0:443
should be displayed, which means this port is being monitored.
Now the 443 port is opened but still not being listened. Check the apache configuration files under /etc/apache2/sites-available
, I found Listen 443
in file. And I configured apache by Certbot, the configuration had no problem.
I had no choice
sudo /etc/init.d/apache2 restart
Then
sudo Isof -iTCP -sTCP:LISTEN -P
I saw apache2 9785 www-data 4u IPv4 448556 0t0 TCP *:443 (LISTEN)
Problem solved~