What are port requirements for remote lisp?
mirko.vukovic at gmail.com
Wed Apr 1 12:59:30 UTC 2020
On Tue, Mar 31, 2020 at 11:51 AM Martin Simmons <martin at lispworks.com>
> >>>>> On Mon, 30 Mar 2020 21:16:00 -0400, Mirko Vukovic said:
> > Hello,
> > My setup is Sly on Spacemacs with Windows 10 running remote lisp on Linux
> > over a corporate network. I have not found a Sly mailing list, and I
> hope I
> > can get an answer here.
> > Emacs is running Sly on Spacemacs on Windows 10. Lisp is running on a
> > server. But Sly does not connect to the listening Lisp. Corporate network
> > security policies have changed. I can ask for IT to accommodate me, but
> > first I need to know what to ask for.
> > So far, I have opened a tunnel, and started a listening lisp (details
> > below).
> > In Emacs I get:
> > sly-connect RET RET RET
> > [sly] Connecting to Slynk on port 4005..
> > helm-M-x-execute-command: make client process failed: Connection timed
> > :name, sly-9, :buffer, nil, :host, hal9000, :service, 4005, :nowait, nil,
> > :tls-parameters, nil
> > The session transcript:
> > > ssh -L4005:localhost:4005 mirko at hal9000
> > [mirko at hal9000 .roswell]$ ros -L ccl-bin run --load
> > Added SLYNK path to ASDF:*CENTRAL-REGISTRY*
> > SLYNK's ASDF loader finished.
> > Loaded ASDF system
> > ;; Slynk started at port: 4005.
> > Created SLYNK server on port 4005
> > Set *USE-DEDICATED-OUTPUT-STREAM* to NIL
> > Clozure Common Lisp Version 1.11.5/v1.11.5 (LinuxX8664)
> > For more information about CCL, please see http://ccl.clozure.com.
> > CCL is free software. It is distributed under the terms of the Apache
> > Licence, Version 2.0.
> > ?
> > My question is as follows:
> > 1. Do I need bi-directional traffic on 4005?
> Assuming you are using the ssh tunnel above, then you don't need port 4005
> traffic on the LAN (it is all hidden in the tunnel).
> The most likely problem is that some firewall on the Windows machine is
> blocking port 4005. You may need to configure that firewall to allow ssh
> listen on localhost:4005 and/or to accept connections to it from Spacemacs.
> In theory you might have similar localhost firewall issues on hal9000, but
> that is less likely.
> > 2. Do I need bi-directional traffic on 22? (after recent changes I
> > cannot ssh or scp into my Windows machine)
> I'm assuming that you ran the ssh command on the Windows 10 machine and it
> gave you a working login to hal9000. If so, then it looks like you already
> have what you need for port 22.
Yes, I can log in to hal9000 with the -L switch:
> ssh -L4005:localhost:4005 mirko at hal9000
Last login: Thu Mar 19 14:33:17 2020 from 172.27.236.189
[mirko at hal9000 ~]$
> Note that bi-directional traffic on a connected socket is different from
> whether you can make a connection in both directions.
> > 3. What tools can I use to try to narrow down the cause of the
> > For instance, can I send a command to the lisp image, and see its
> > on the lisp side?
> Firstly, run "netstat -antp" on hal9000 to see if Lisp is listening on port
It looks that ccl-bin is listening:
$ sudo netstat -antp | grep :4005
tcp 0 0 127.0.0.1:4005 0.0.0.0:* LISTEN
> Secondly, run "netstat -anop tcp" on the Windows 10 machine to see if ssh
> listening on port 4005.
I have Msys2's netstat. On the laptop:
> which netstat
> netstat -anop tcp | grep :4005
TCP 127.0.0.1:4005 0.0.0.0:0 LISTENING 12052
> Thirdly, run "ssh -p 4005 localhost" on the Windows 10 machine. This use a
> ssh is very bogus, but it should at least give an error message with some
> diagnostics. (Normally I would use telnet for this, but it is not
> on Windows 10 by default.)
Outputs of both ssh and telnet on the laptop:
> which telnet
> telnet localhost 4005
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.
> ssh -p 4005 localhost
kex_exchange_identification: read: Connection reset by peer
Summarizing: of the tests you suggested, all pass but the last one (to ssh
or telnet into port 4005).
Thank you for your assistance so far,
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