[network][easy case]troubleshoting the connection to a remote server

background & issue

I deployed a minio server on an ECS(a vps in alibaba), but I couldn't access it on local PC. It's an easy case but very common when connecting to a new server. so I record my brief procedure here in case you come into similar situation.

steps how I trouble shot and fix it

• check the connection

  telnet <ip> <port>
  

  of course it couldn't connect.
• check the port status is OK on remote server

  netstat -anp | grep <port>
  

  it's healthy.
• config the 'security group rule' on console(aliyun)
  here I opened all ports for testing convenience. but failed when checking the connectiong again
• check the firewall in remote server
  login in server and

  sudo ip6tables -L -n -v
  sudo iptables -A INPUT -p tcp --dport <port> -j ACCEPT # add a rule for allowing traffic via <port>
  

  then the connection worked.