Incorrect response when sending http request in telnet mode

[zhengshuxin]

I telnet the server port listened by asmhttpd and after sending the first line of http request, and the error response got: Trying 0.0.0.0... Connected to 0. Escape character is '^]'. GET / HTTP/1.1 HTTP/1.1 400 Bad Request Server: asmttpd/0.4.5

But when I send http request by curl, the response is ok. $ curl "http://127.0.0.1:8081/" -v

• Trying 127.0.0.1:8081...
• TCP_NODELAY set
• Connected to 127.0.0.1 (127.0.0.1) port 8081 (#0)

GET / HTTP/1.1 Host: 127.0.0.1:8081 User-Agent: curl/7.65.3 Accept: /

• Mark bundle as not supporting multiuse < HTTP/1.1 200 OK < Server: asmttpd/0.4.5 < Accept-Ranges: bytes < Content-Length: 78 < Content-Type: text/html <

hello world