網路服務連線測試: Difference between revisions

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如何測試與排除網路服務連線問題。找出問題發生的地方：(1) 伺服器上的本地服務 (localhost) (2) 從區域網路到伺服器 (3) 從廣域網路到伺服器
如何測試與排除網路服務連線問題。找出問題發生的地方：(1) 伺服器上的本地服務 (localhost) (2) 從區域網路到伺服器 (3) 從廣域網路到伺服器


: [[Test connectivity for the web service]] in English
{{LanguageSwitcher | content = [[Test connectivity for the web service | EN]], [[網路服務連線測試 | 漢字]] }}


=== 如何連線到網路服務 (Web 服務) ===
=== 如何連線到網路服務 (Web 服務) ===
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# {{kbd | key = telnet 127.0.0.1 <PORT>}} 如果連接網頁服務失敗。它將顯示消息："telnet: 無法連接到遠程主機：連接被拒絕"
# {{kbd | key = telnet 127.0.0.1 <PORT>}} 如果連接網頁服務失敗。它將顯示消息："telnet: 無法連接到遠程主機：連接被拒絕"


如果安裝了Python，則使用替代網站服務
如果安裝了 Python 或 Node.js，則可使用替代網站服務


* (對於python 2.x) {{kbd | key=<nowiki>python -m SimpleHTTPServer <port></nowiki>}}<ref>[https://docs.python.org/2/library/simplehttpserver.html 20.19. SimpleHTTPServer — 簡單HTTP請求處理器 — Python 2.7.17 文件]</ref>
* (適用 python 3.x) {{kbd | key=<nowiki>python -m http.server <port></nowiki>}} (預設 port: 8000)<ref>[https://docs.python.org/3/library/http.server.html http.server — HTTP servers — Python 3.13.2 documentation]</ref>
* (對於python 3.x) {{kbd | key=<nowiki>python -m http.server <port></nowiki>}}<ref>[https://docs.python.org/3.8/library/http.server.html?highlight=http%20server#module-http.server http.server — HTTP伺服器 — Python 3.8.1 文件]</ref>
* (適用 Node.js) {{kbd | key=<nowiki>npx http-server -p <port></nowiki>}} (預設 port: 8080)<ref>[https://github.com/http-party/http-server http-server: a simple static HTTP server]</ref>


== 測試本地網路服務的連接性 ==
== 測試本地網路服務的連接性 ==
WAN &#9675; -------&gt; &#9675; LAN -------&gt; <span style="color:red">&#9679; 伺服器</span>
WAN &#9675; -------&gt; &#9675; LAN -------&gt; <span style="color:red">&#9679; 伺服器</span>


: [[Image:Owl icon.jpg]] 如果您有管理權限通過SSH或遠程桌面服務登錄伺服器。
{{Tips}} 如果您有管理權限通過SSH或遠程桌面服務登錄伺服器。


=== 檢查您的電腦/伺服器是否被指派了IP位址 ===
=== 檢查您的電腦/伺服器是否被指派了IP位址 ===
Line 92: Line 92:
[https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers 維基百科 - TCP和UDP埠號列表]
[https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers 維基百科 - TCP和UDP埠號列表]


 
Example output of netstat command, more on [[Find process running on port]]
[[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>
<pre>
$ netstat -tulpn | grep LISTEN
$ netstat -tulpn | grep LISTEN
Line 110: Line 100:
// means the 80 port service is running
// means the 80 port service is running
</pre>
</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 ===
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# [http://check-host.net/ Check server: Check host - online website monitoring, Check IP] "checks the possibility of a TCP connection to host's specified port from different locations around the world." quoted from website. {{access | date=2015-08-02}}
# [http://check-host.net/ Check server: Check host - online website monitoring, Check IP] "checks the possibility of a TCP connection to host's specified port from different locations around the world." quoted from website. {{access | date=2015-08-02}}


== Related articles ==
 
== 相關文章 ==
* [https://errerrors.blogspot.com/2022/07/blog-post.html 怎樣排除網路連線逾時 (network connection timed out) 問題]
* [https://errerrors.blogspot.com/2022/07/blog-post.html 怎樣排除網路連線逾時 (network connection timed out) 問題]


Latest revision as of 17:07, 26 March 2025

如何測試與排除網路服務連線問題。找出問題發生的地方：(1) 伺服器上的本地服務 (localhost) (2) 從區域網路到伺服器 (3) 從廣域網路到伺服器

🌐 Switch language: EN, 漢字


如何連線到網路服務 (Web 服務)[edit]

如果服務是網站伺服器 (web service)：

  • (1) 打開瀏覽器，(2) 輸入地址：http://127.0.0.1 或 http://the.domain
  • Linux Lynx 指令：
    1. (如果尚未安裝lynx，則為可選操作) yum install lynx 適用於CentOS / sudo apt-get install lynx 適用於Ubuntu[1]
    2. lynx http://127.0.0.1 [2] 適用於Linux Os linux.png
  • telnet 指令
    1. telnet 127.0.0.1 <PORT> 例如 telnet 127.0.0.1 80 或 telnet the.domain 80
    2. (在telnet連接80埠後，輸入) get + SPACE[3]
  • curl[4]: curl -vL http://IP:Port
    • (如果尚未安裝curl指令，則為可選操作) 在Windows/MacOSX/Linux上安裝和運行cURL | Ubidots幫助中心
    • 指令範例：
      • (1) 使用 curl -voL https://www.google.com 將輸出寫入<file>而非stdout
      • (2) 使用 curl -vL https://www.google.com 或 curl -voL /dev/null https://www.google.com 將輸出寫入stdout
      • (3) 使用 curl -vOL https://www.google.com/index.html 將輸出寫入<file>並使用遠程檔案名
    • 如果失敗，將顯示消息："failed: Connection refused"
  • Linux wget 軟體例如 wget https://www.google.com
  • 使用第三方網站監控服務：Web Ping

如果服務不是網站伺服器，則使用telnet

  1. (可選) 在Win Os windows.png 上安裝Telnet用戶端 | Microsoft文件。在macOS high Sierra上重啟telnet – Ayuth Mangmesap (blackSource) – Medium 在macOS icon_os_mac.png
  2. telnet 127.0.0.1 <PORT> 如果連接網頁服務失敗。它將顯示消息："telnet: 無法連接到遠程主機：連接被拒絕"

如果安裝了 Python 或 Node.js，則可使用替代網站服務

  • (適用 python 3.x) python -m http.server <port> (預設 port: 8000)[5]
  • (適用 Node.js) npx http-server -p <port> (預設 port: 8080)[6]

測試本地網路服務的連接性[edit]

WAN ○ -------> ○ LAN -------> ● 伺服器

Owl icon.jpg 如果您有管理權限通過SSH或遠程桌面服務登錄伺服器。

檢查您的電腦/伺服器是否被指派了IP位址[edit]

  • Linux Os linux.png ：(1) 檢查IP位址。ifconfig。 (2) 重新分配IP位址並重新啟動網路服務。service network restart 用於CentOS[7]
  • Win Os windows.png ：檢查IP位址。ifconfig/all
  • 更多關於網路問題

檢查網路服務是否已成功啟動？[edit]

  • Apache /etc/init.d/httpd status 在CentOS7上 [8]
  • nginx sudo service nginx status 在CentOS7上
  • Docker容器 docker ps 檢查容器是否在運行和暴露埠口[9]

檢查MySQL是否已成功啟動？[edit]

使用lsof指令[edit]

lsof -i:3306 在macOS icon_os_mac.png 或Linux Os linux.png 在Unix類操作系統中用於列出打開的文件及打開它們的進程。

  • lsof：這代表"列出打開的文件"。它是一個命令行工具，顯示有關由進程打開的文件的資訊。在Unix和Linux中，一切都被視為文件（包括硬體設備、套接字和目錄），因此lsof是系統管理員監控和排除系統行為問題的強大工具。
  • -i：這個選項告訴lsof僅顯示網絡文件。在Unix和Linux中，網絡連接被視為文件。-i選項可用於根據互聯網地址或網絡協議過濾連接。
  • :3306：這指定了埠號。埠3306通常被MySQL使用，這是一個流行的數據庫管理系統。通過包括:3306，您要求lsof列出所有與埠3306相關的網絡文件（包括套接字連接）。

輸出範例：localhost:mysql (LISTEN) 意味著MySQL已成功啟動 

COMMAND     PID      USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mysqld    93034 account   29u  IPv4 0xxxx      0t0  TCP localhost:mysql (LISTEN)

使用ps指令[edit]

ps aux | grep mysql 在macOS icon_os_mac.png

如果MySQL已成功啟動的輸出範例： 

_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

如果MySQL沒有成功啟動的示例輸出： 

ACCOUNT        12349   0.0  0.0 408645328   1648 s011  S+    2:14下午   0:00.00 grep mysql

檢查埠是否被其他進程佔用？[edit]

檢查埠是否被其他協議使用

SG TCP/IP埠數據庫 維基百科 - TCP和UDP埠號列表

Example output of netstat command, more on Find process running on port 

$ netstat -tulpn | grep LISTEN

tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      - 

// means the 80 port service is running

Check if a port is blocked by browser[edit]

Check if a port is blocked by browser[10]


Is the port opened for external users?[edit]

Check the OS firewall or protected by antivirus software

    • Linux Os linux.png
      • iptables: (1) iptables -L to list all rules[11] (2) rule with smaller line-number will override the rule with larger line-number[12]
      • FirewallD rules: (1) sudo firewall-cmd --get-default-zone return 'public' (2) sudo firewall-cmd --list-all --zone=public[13] (3) Allow port with FirewallD
      • SELinux Policy Management: (1) After installed policycoreutils-python[14], input semanage port -l to list open ports. (2) Allow port with semanage.
    • Win Os windows.png Windows Firewall with Advanced Security -> configure firewall rules
    • protected by antivirus software?
  • connect to localhost ex: telnet 127.0.0.1 23 where 23 is the port number where the service running
    • Install Telnet Client on Win Os windows.png
    • if the local service is web server, you can also try lynx http://127.0.0.1 for Linux Os linux.png
  • double check the server/service logs

Test connectivity from LAN to the server[edit]

WAN ○ -------> ● LAN -------> ● server

Testing on LAN (local network, subnet scope): The different servers between LAN or with the same ip class (ex: 1.2.3.*) and may not have the firewall limit. Private network / Private IP address

  • Is the service alive?
  • Connect to the internal IP eg: telnet 172.18.0.1 23 (1) IP start with 172.18... is Private IP Network Numbers (2) where 23 is the port number where the service running
  • If the local service is web server, you can also try to connect the internal IP e.g. lynx http://172.18.0.1 for Linux Os linux.png
  • Double check the server/service logs
  • Is the internal IP correct?

Test connectivity from WAN to the remote server[edit]

WAN ● -------> ● LAN -------> ● server

We met the trouble on WAN (wide area network). If we do no have the administrative permission, the tests we can do as follows:

other issue:

Tools[edit]

  1. Good.gif CurrPorts: Monitoring TCP/IP network connections on Windows
  2. PFPortCheck Program: check TCP/UDP port from localhost(where you installed the program) to portforward.com
  3. TCPView for Windows
  4. Check server: Check host - online website monitoring, Check IP "checks the possibility of a TCP connection to host's specified port from different locations around the world." quoted from website. [Last visited: 2015-08-02]


相關文章[edit]

References[edit]

  1. ↑ 在Ubuntu上安裝和使用Lynx瀏覽器
  2. ↑ Lynx使用者指南 v2.8.7
  3. ↑ 使用Telnet指令檢查HTTP埠口80
  4. ↑ curl - 使用方法
  5. ↑ http.server — HTTP servers — Python 3.13.2 documentation
  6. ↑ http-server: a simple static HTTP server
  7. ↑ 如何重新啟動網路服務？ - Ask Ubuntu
  8. ↑ 如何檢查LAMP堆棧的運行狀態 | E2E Networks知識庫
  9. ↑ docker ps | Docker文件
  10. ↑ 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
  11. ↑ HowTos/Network/IPTables - CentOS Wiki
  12. ↑ How to edit iptables rules - FedoraProject
  13. ↑ How To Set Up a Firewall Using FirewallD on CentOS 7 | DigitalOcean
  14. ↑ semanage command not found on CentOS 7 and RHEL 7
  15. ↑ networking - Command for determining my public IP? - Ask Ubuntu


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