What does "Server ****** is not blacklisted" means in curl verbose output? [closed]

Why should the server be blacklisted ?

By curl or another program ?

How server can get blacklisted ?

Is it server or program dependant ?

Is this the IP address that get blacklisted, or the name of the server in the http answer ?

PS : I don't know if it is relevant, but i'm running on Linux / Ubuntu.

Here is the full output (testing tornado in localhost)

> * Rebuilt URL to: localhost:8888/
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8888 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.35.0
> Host: localhost:8888
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Fri, 16 May 2014 16:35:40 GMT
< Content-Length: 12
< Etag: "e02aa1b106d5c7c6a98def2b13005d5b84fd8dc8"
< Content-Type: text/html; charset=UTF-8
* Server TornadoServer/3.2 is not blacklisted
< Server: TornadoServer/3.2
< 
* Connection #0 to host localhost left intact
Hello, world

Solution 1:

It is an internal message from curl.

See: https://github.com/bagder/curl/blob/master/lib/pipeline.c

Seems to be part of a curl feature related to pipelining.

bool Curl_pipeline_server_blacklisted(struct SessionHandle *handle,
                                      char *server_name)
{
...
    infof(handle, "Server %s is not blacklisted\n", server_name);