Editing Test connectivity for the web service (section)

== Test connectivity for the local web service ==
WAN &#9675; -------&gt; &#9675; LAN -------&gt; <span style="color:red">&#9679; server</span>

{{Tips}} If you has administrative permission to log into the server via SSH or Remote desktop service.

=== Check if your computer/server Is being assigned the IP Address ===

* {{Linux}}: (1) Check the IP Address. {{kbd | key = ifconfig}}. (2) Re-assign the IP Address and restart the networking service. {{kbd | key = service network restart}} for CentOS<ref>[http://askubuntu.com/questions/230698/how-to-restart-the-networking-service How to restart the networking service? - Ask Ubuntu]</ref>
* {{Win}}: Check the IP Address. {{kbd | key = ifconfig/all}} 
* More on [[Network problem]]

=== Check if web service has started successfully? ===
* Apache {{kbd | key = /etc/init.d/httpd status}} on CentOS7 <ref>[https://www.e2enetworks.com/help/knowledge-base/how-to-check-running-status-of-lamp-stack/ How to check running status of LAMP stack | E2E Networks Knowledgebase]</ref>
* nginx {{kbd | key = sudo service nginx status}} on CentOS7 
* Docker container {{kbd | key = docker ps}} to check if the container is running & expose the port<ref>[https://docs.docker.com/engine/reference/commandline/ps/ docker ps | Docker Documentation]</ref>

=== Check if MySQL has started successfully? ===
==== Using lsof command ==== 
* {{kbd | key = lsof -i:3306}} on {{Mac}} or {{Linux}}

The command lsof -i:3306 is used in Unix-like operating systems to list open files and the processes that opened them. Let's break down the command:

lsof: This stands for "List Open Files". It's a command-line utility that displays information about files opened by processes. In Unix and Linux, everything is treated as a file (including hardware devices, sockets, and directories), so lsof is a powerful tool for system administrators to monitor and troubleshoot system behavior.

-i: This option tells lsof to show only network files. In Unix and Linux, network connections are treated as files. The -i option can be used to filter connections based on the Internet address or network protocol.

:3306: This specifies the port number. Port 3306 is commonly used by MySQL, a popular database management system. By including :3306, you are asking lsof to list all network files (which includes socket connections) that are associated with port 3306.

Example output: localhost:mysql (LISTEN) means the MySQL has started successfully
<pre>
COMMAND     PID      USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mysqld    93034 account   29u  IPv4 0xxxx      0t0  TCP localhost:mysql (LISTEN)
</pre>

==== Using ps command ==== 
* {{kbd | key = <nowiki>ps aux | grep mysql</nowiki>}} on {{Mac}}

Example output if MySQL has started successfully:
<pre>
_mysql           11083   0.3  0.2 409657280  31424   ??  Ss    2:12下午   0:01.07 /usr/local/mysql/bin/mysqld --user=_mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --plugin-dir=/usr/local/mysql/lib/plugin --log-error=/usr/local/mysql/data/mysqld.local.err --pid-file=/usr/local/mysql/data/mysqld.local.pid --keyring-file-data=/usr/local/mysql/keyring/keyring --early-plugin-load=keyring_file=keyring_file.so
ACCOUNT        12349   0.0  0.0 408645328   1648 s011  S+    2:14下午   0:00.00 grep mysql
</pre>

Example output if MySQL has NOT started successfully:
<pre>
ACCOUNT        12349   0.0  0.0 408645328   1648 s011  S+    2:14下午   0:00.00 grep mysql
</pre>

=== Check if a port was occupied by other process? ===
Check the port if used by other protocol
* [https://www.speedguide.net/ports.php SG TCP/IP Ports Database]
* [https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers List of TCP and UDP port numbers - Wikipedia]

[[Find process running on port]]

* {{Linux}} 
** [http://linux.die.net/man/1/nmap nmap] "Network exploration tool and security / port scanner." e.g. {{kbd | key = <nowiki>nmap -p 80,443 ip</nowiki>}}
** [http://linux.die.net/man/8/ss ss] "utility to investigate sockets" e.g. {{kbd | key = <nowiki>ss -tnlp | grep 80</nowiki>}} or using OR operator<ref>[http://www.thegeekstuff.com/2011/10/grep-or-and-not-operators/ 7 Linux Grep OR, Grep AND, Grep NOT Operator Examples]</ref> {{kbd | key = <nowiki>ss -tnlp | grep '80\|443'</nowiki>}}
** [http://linuxcommand.org/man_pages/ps1.html ps] List the current processes. Input {{kbd | key = <nowiki>ps -aux | grep "PORT_NUMBER"</nowiki>}} e.g. {{kbd | key = <nowiki>ps -aux | grep 443</nowiki>}}
** [https://docs.oracle.com/cd/E19504-01/802-5753/6i9g71m3i/index.html netstat Command] {{kbd | key=<nowiki>netstat -tulpn | grep LISTEN</nowiki>}} e.g. 
** [https://docs.docker.com/engine/reference/commandline/port/ docker port | Docker Documentation]

Example output of netstat command
<pre>
$ netstat -tulpn | grep LISTEN

tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      - 

// means the 80 port service is running
</pre>

* {{Win}} 
** Using the software [http://www.nirsoft.net/utils/cports.html CurrPorts] to check the process and port. e.g. Apache will not running if the 80 port was occupied by skype<ref>[http://stackoverflow.com/questions/4705005/how-to-solve-wamp-and-skype-conflict-on-windows-7 How to solve WAMP and Skype conflict on Windows 7? - Stack Overflow]</ref>.

=== Check if a port is blocked by browser ===
Check if a port is blocked by browser<ref>[https://blog.miniasp.com/post/2022/05/02/Dont-use-ERR_UNSAFE_PORT-for-your-website?fbclid=IwAR2y9D60H-j8-5T1zJixTU-L2ydbn7LgnWpG1v53fyaKCyuuqx2MqfU80fI 開發與部署網站時需注意不要使用到 ERR_UNSAFE_PORT 不安全的埠號 | The Will Will Web]</ref>
* {{Chrome}} [https://chromium.googlesource.com/chromium/src.git/+/refs/heads/master/net/base/port_util.cc#52 net/base/port_util.cc - chromium/src.git - Git at Google]
* [https://fetch.spec.whatwg.org/#port-blocking Fetch Standard] 2.9. Port blocking


=== Is the port opened for external users? ===
Check the OS firewall or protected by antivirus software

** {{Linux}}
*** [http://linux.die.net/man/8/iptables iptables]: (1) {{kbd | key = iptables -L}} to list all rules<ref>[http://wiki.centos.org/HowTos/Network/IPTables HowTos/Network/IPTables - CentOS Wiki]</ref> (2) rule with smaller line-number will override the rule with larger line-number<ref>[https://fedoraproject.org/wiki/How_to_edit_iptables_rules?rd=User_talk:Rforlot How to edit iptables rules - FedoraProject]</ref>
*** [https://fedoraproject.org/wiki/FirewallD FirewallD] rules: (1) {{kbd | key = <nowiki>sudo firewall-cmd --get-default-zone</nowiki>}} return 'public' (2) {{kbd | key = <nowiki>sudo firewall-cmd --list-all --zone=public</nowiki>}}<ref>[https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-using-firewalld-on-centos-7 How To Set Up a Firewall Using FirewallD on CentOS 7 | DigitalOcean]</ref> (3) Allow port with FirewallD
*** [http://linux.die.net/man/8/semanage SELinux Policy Management]:  (1) After installed {{kbd | key =policycoreutils-python}}<ref>[http://sharadchhetri.com/2014/10/07/semanage-command-found-centos-7-rhel-7/ semanage command not found on CentOS 7 and RHEL 7]</ref>, input {{kbd | key = <nowiki>semanage port -l</nowiki>}} to list open ports. (2) Allow port with semanage.
** {{Win}} [https://technet.microsoft.com/en-us/library/cc754274.aspx?f=255&MSPPError=-2147217396 Windows Firewall with Advanced Security] -> configure firewall rules
** protected by antivirus software?
* connect to localhost ex: {{kbd | key= telnet 127.0.0.1 23}} where 23 is the port number where the service running
** [https://technet.microsoft.com/en-us/library/cc771275(v=ws.10).aspx Install Telnet Client] on {{Win}}
** if the local service is web server, you can also try  {{kbd | key = <nowiki>lynx http://127.0.0.1</nowiki>}} for {{Linux}}
* double [[Testing#check_the_server.2Fservice_logs | check the server/service logs]]