make-network-process timing out when connecting swank server

Vladimir Sedach vas at
Mon Apr 20 16:06:31 UTC 2020

Mirko Vukovic <mirko.vukovic at> writes:

>> On Sun, 19 Apr 2020 at 01:08, Mirko Vukovic <mirko.vukovic at>
>> wrote:
>> > Nevertheless, sly-connect still fails. Stepping through the code, I came
>> to a call to make-network-process, which is a C function.
>> >
>> > The error message is
>> > "make client process failed", "Connection timed out", :name, "sly-4",
>> :buffer, nil, :host, "", :service, 4005, :nowait, nil,
>> :tls-parameters, nil
>> Does telneting to port 4005 work?
> I have a swank server listening on port 4005. telnet times out:
>> telnet hal9000 4005
> Trying
> telnet: Unable to connect to remote host: Connection timed out
>> Why don't you
>> connect to SWANK via the SSH tunnel you've established?
> If you mean by slime-connect, it times out.
> If you mean by telnet, it works:
>> telnet localhost 4005
> Trying ::1...
> Connected to localhost.
> Escape character is '^]'.

You need to figure out what arguments are being passed to
make-network-process and then try to reproduce by calling
make-network-process directly (see Section 38.17.1
‘make-network-process’ of the elisp Info manual).

One possible problem could be that SLIME is trying to connect to instead of localhost, which is the IPv6 ::1 loopback
address on your system.

Vladimir Sedach
Software engineering services in Los Angeles

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