Checking refusal of a network connection

[Michael Torrie]

On 06/01/2019 11:15 AM, Markus Elfring wrote:
>>> connect(3, {sa_family=AF_INET, sin_port=htons(37351), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 ECONNREFUSED (Connection refused)
>>
>> 	Without seeing the code, I'd be suspicious of that difference.
> 
> I would expect that the IPv4 address from such a connection attempt
> would be automatically converted to a IPv6 loopback address.

How would this conversion take place?  Localhost is 127.0.0.1.
Localhost6 is ::1.  They are different and you cannot route between the two.

What I can see is that your server binds to localhost6 and your client
is trying to connect to localhost.

> Unfortunately, the direct specification “… socket-send_json_data.py --server_id ::1 …”
> does not work at the moment because of the error message “socket.gaierror: [Errno -9]
> Address family for hostname not supported”.

No idea on that one.