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Editor to share with you how to deal with port availability detection when ping can be connected but the port is not available. I believe most people don't know much about it, so share this article for your reference. I hope you will learn a lot after reading this article. Let's learn about it together.

Port availability probe description when ping can be reached but the port is not connected

Introduction to Port availability probe tool

Different operating systems use different tools for port availability detection.

Introduction of Port availability Detection tools in Linux Environment

Traceroute is a network testing tool pre-installed with almost all Linux distributions to track the path that Internet Protocol (IP) packets take when they are delivered to the destination address. You can probe port availability through the traceroute tool.

Traceroute detects the connectivity of the corresponding port on the entire link from the packet source to the destination server by sending TCP packets to the destination port. Common uses of traceroute port availability probe are as follows:

Traceroute [- n]-T-p Host

Example

[root@centos~] # traceroute-n-T-p 22 223.5.5.5traceroute to 223.5.5.5 (223.5.5.5), 30 hops max 60 byte packets 1 58.96.171.249 0.431 ms 0.538 ms 0.702 ms 2 10.88.16.29 0.997 ms 1.030 ms 10.88.16.21 1.309 ms 3 58.96.160.246 0.393 ms 0.390 ms 58.96.160.250 0.423 ms 4 63.218.56.237 1.110 ms 202.123.74.122 0.440 ms 0.440 ms 5 63.223.15.90 1.744 ms 63.218. 56.237 1.076 ms 1.232 ms 6 63.223.15.158 1.832 ms 63.223.15.90 1.663 ms 63.223.15.74 1.616 ms 7 202.97.122.113 2.776 ms 63.223.15.154 1.585 ms 1.606 ms 8 * * 202.97.122.113 2.537 ms 9 202.97.61.237 6.856 ms * * 10 * 11 * 12 * * 119.147.220.222 8.738 ms13 119.147.220.230 8.248 ms 8.231 ms * 14 * 42.120.242.230 32.305 ms 42.120.242.226 29.877 ms15 42.120.242.234 11.950 ms 42.120.242.222 23.853 ms 42.120.242.218 29.831 ms16 42.120.253.2 11.007 ms 42.120.242.234 13.615 ms 42.120.253.2 11.956 ms17 42.120.253.14 21.578 ms 42.120.253.2 13.236 ms * 18 * * 223.5.5.5 12.070 ms! X

Parameter description

-n directly use the IP address instead of the host name (disable DNS backchecking).

-T is detected by TCP.

-p probes the destination port number.

Host target server domain name or IP.

For more information about the use of traceroute, you can check out the man help.

Introduction of Port availability Detection tools in Windows Environment

In Windows environment, you can use tracetcp to detect port availability.

Tracetcp also detects the link by sending TCP packets to analyze whether there are link intermediate nodes blocking the target port.

Download and install

The use of tracetcp depends on WinPcap library, so you need to download it from the official website.

Click here to download the latest version of tracetcp on the official website. Alternatively, you can download the attachment v1.0.2 version of tracetcp (which may not be the latest version).

Extract the downloaded tracetcp-related files directly to the C:\ Windows directory. (if you extract it to a non-system directory, you need to manually modify the system environment variables to ensure that the instructions can be called directly.)

Usage

Double-click to open the tracetcp application. The common uses of tracetcp are as follows:

Tracetcp:

Example

C: > tracetcp www.aliyun.com:80Tracing route to 140.205.63.8 on port 80Over a maximum of 30 hops.1 3 ms 4 ms 3 ms 30.9.176.12 13 ms 3 ms 4 ms 10.64.200.333 3 ms 3 ms 2 ms 10.64.1.14 4 ms 3 ms 3 ms 42.120.74.45 5 ms 4 ms 7 ms 42. 120.253.2336 6 ms 5 ms 7 ms 42.120.247.977 8 ms 8 ms 8 ms 42.120.247.978 10 ms 10 ms 8 ms 123.56.34.2469 9 ms 9 ms 11 ms 42.120.243.11710 * Request timed out.11 Destination Reached in 8 ms. Connection established to 140.205.63.8Trace Complete.

For more information about tracetcp parameters, you can use tracetcp -? Get and view.

Port availability probe step

In general, you can:

As mentioned earlier, the corresponding tool is used to detect the availability of the destination port of the destination address.

Check and analyze the detection results and determine the abnormal nodes.

Through ip.taobao.com and other IP address query websites to get the corresponding nodes belong to the operator and the network.

Or submit a work order, Aliyun will give you feedback to the relevant operators.

Brief introduction to the Analysis of Link Test results

Abnormal node determination method: if the relevant port is blocked at a certain hop, then each hop will not return data. Based on this, the abnormal node can be determined.

Example 1

C: > tracetcp www.aliyun.com:135Tracing route to 115.239.210.27 on port 135Over a maximum of 30 hops.1 3 ms 3 ms 3 ms 30.9.176.12 4 ms 3 ms 3 ms 10.64.200.333 3 ms 3 ms 3 ms 10.64.1.14 * Request timed out.5 * * * Request timed out.6 * Request timed out.7 * Request timed out.8 * Request timed out.9 * Request timed out.10 * Request timed out. 11 * Request timed out.12 * Request timed out.13 * Request timed out.14 * Request timed out.15 * Request timed out.16 * * * Request timed out.17 * Request timed out.18 * Request timed out.19 * Request timed out.20 * Request timed out.21 * Request timed Out.22 * Request timed out.23 * Request timed out.24 * Request timed out.25 * Request timed out.26 * Request timed out.27 * * * Request timed out.28 * Request timed out.29 * Request timed out.30 * Request timed out.Trace Complete.

In the above probe data, no data is returned from the target port after the third hop. Indicates that the corresponding port is blocked at this node.

Example conclusion: because this node is a private network IP, which may be caused by the relevant security policies of the local network, you need to contact the local network manager for further troubleshooting and analysis.

Example 2

[root@mycentos] # traceroute-T-p 135 www.baidu.comtraceroute to www.baidu.com (111.13.100.92), 30 hops max 60 byte packets 1 * 2 192.168.17.20 (192.168.17.20) 4.115 ms 4.397 ms 4.679 ms 3 111.20.41 (111.1.20.41) 901.921 ms 902.762 ms 902.338 ms 4 111.34.197 (111.34.197) 2.187 ms 1.392 ms 2.266 ms 5 * 6 221.183.19.169 (221.183. 19.169) 1.688 ms 1.465 ms 1.475 ms 7 221.183.11.105 (221.183.11.105) 27.729 ms 27.708 ms 27.636 ms 8 * 9 * 10 111.13.98.249 (111.13.98.249) 28.922 ms 111.13.98.253 (111.13.98.253) 29.030 ms 28.916 ms11 111.13.108.22 (111.13. 108.22) 29.169 ms 28.893 ms 111.13.108.33 (111.13.108.33) 30.986 ms12 * 13 * 14 * 15 * 17 * 18 * 19 * 20 * 21 * 22 * 23 * 24 * * 25 * 26 * 27 * 28 * 29 * 30 *

In the above probe data, no data is returned from the target port after the 11th hop. Indicates that the corresponding port is blocked at this node.

Conclusion: because the node belongs to Beijing Mobile after query, you need to check it yourself or submit a ticket for further investigation and analysis.

The above is all the contents of the method of port availability detection when the ping can be reached but the port is not. Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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