Curl is a command line tool and library which implements protocols like HTTP, HTTPS, FTP etc. Curl also supports HTTPS protocol which is secure version of the HTTP. Using curl may create some problems. We will examine how to solve these curl HTTPS related problems.
We will start with the installation of the curl tool with the following command.
Ubuntu, Debian, Mint, Kali:
Fedora, CentOS, RHEL:
- CURL is a tool for data transfer. It is also available as a library for developers and as a CLI for terminal-based use cases. Both have the same engine inside (Truth is that CLI tool is just the program that uses the library under the hood).
- Curl -resolve 'myservice.com:8090:2.2.2.2' 'curl simply ignores the port and goes with 443. Of-course, this causes the DNS cache to miss and I end-up using the public DNS IP.
- $ curl -x socks5://james:cats@myproxy.com:8080 上面命令指定 HTTP 请求通过 myproxy.com:8080 的 socks5 代理发出。 如果没有指定代理协议，默认为 HTTP。.
- Curl will normally always first attempt to use EPRT, then LPRT before using PORT, but with this option, it will use PORT right away. EPRT and LPRT are extensions to the original FTP protocol, may not work on all servers but enable more functionality in a better way than the traditional PORT command.
Especial in self-signed or expired X.509 or SSL/TLS certificates may create problems. The error detail is printed to the terminal. As an example, we will try to access https://www.wikipedia.com and we will get an error like
If your Windows 10 build is 17063, or later, cUrl is included by default. All you need to do is run Command Prompt with administrative rights and you can use cUrl. The Curl.exe is located at C: Windows System32. If you want to be able to use cUrl from anywhere, consider adding it to Path Environment Variables. CUrl On Windows 7, 8/8.1.
Curl Port Test
AND we run following command.
In order to prevent this error and accept an insecure certificate, we need to provide--insecure This will accept all provided certificates without complaining about it.
If we do not want to use web site provided certificate and provide sites HTTPS certificate manually we can use -E or --cert option with the certificate file. In this example, we will use a certificate named inwk.cert order to connect https://www.wikipedia.com.
Curl Port Test
In some cases, we may need to use another certificate chain then internet. Certificate chains provide a trust relationship between hierarchical certificates where the leaf is the site certificate we want to navigate. Certificate Authority is the top certificate which is provided by Certification Authority firms. We can provide another certificate authority like our company local certificate authority with the --cacert option.