问题
How to get a web page's content using Telnet?
For example, the content of https://stackoverflow.com/questions.
回答1:
telnet ServerName 80
GET /index.html↵
↵
↵ means 'return', you need to hit return twice
回答2:
You could do
telnet stackoverflow.com 80
And then paste
GET /questions HTTP/1.0
Host: stackoverflow.com
# add the 2 empty lines above but not this one
Here is a transcript
$ telnet stackoverflow.com 80
Trying 151.101.65.69...
Connected to stackoverflow.com.
Escape character is '^]'.
GET /questions HTTP/1.0
Host: stackoverflow.com
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
...
回答3:
For posterity, your question was how to send an http request to https://stackoverflow.com/questions. The real answer is: you cannot with telnet, cause this is an https-only reachable url.
So, you might want to use openssl instead of telnet, like this for instance
$ openssl s_client -connect stackoverflow.com:443
...
---
GET /questions HTTP/1.1
Host: stackoverflow.com
This will give you the https response.
回答4:
To somewhat expand on earlier answers, there are a few complications.
telnet is not particularly scriptable; you might prefer to use nc (aka netcat) instead, which handles non-terminal input and signals better.
Also, unlike telnet, nc actually allows SSL (and so https instead of http traffic -- you need port 443 instead of port 80 then).
There is a difference between HTTP 1.0 and 1.1. The recent version of the protocol requires the Host: header to be included in the request on a separate line after the POST or GET line, and to be followed by an empty line to mark the end of the request headers.
The HTTP protocol requires carriage return / line feed line endings. Many servers are lenient about this, but some are not. You might want to use
printf "%\r\n" \
"GET /questions HTTP/1.1" \
"Host: stackoverflow.com" \
"" |
nc --ssl stackoverflow.com 443
If you fall back to HTTP/1.0 you don't always need the Host: header, but many modern servers require the header anyway; if multiple sites are hosted on the same IP address, the server doesn't know from GET /foo HTTP/1.0 whether you mean http://site1.example.com/foo or http://site2.example.net/foo if those two sites are both hosted on the same server (in the absence of a Host: header, a HTTP 1.0 server might just default to a different site than the one you want, so you don't get the contents you wanted).
The HTTPS protocol is identical to HTTP in these details; the only real difference is in how the session is set up initially.
来源：https://stackoverflow.com/questions/15772355/how-to-send-an-http-request-using-telnet