What are port requirements for remote lisp?
Mirko Vukovic
mirko.vukovic at gmail.com
Thu Apr 2 12:33:42 UTC 2020
On Thu, Apr 2, 2020 at 7:55 AM Martin Simmons <martin at lispworks.com> wrote:
> >>>>> On Wed, 1 Apr 2020 08:59:30 -0400, Mirko Vukovic said:
> >
> > On Tue, Mar 31, 2020 at 11:51 AM Martin Simmons <martin at lispworks.com>
> > wrote:
> >
> > > >>>>> 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
> > > Linux
> > > > 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
> > > out,
> > > > :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
> > > start-slynk-server.lisp
> > > >
> > > > 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
> > > to
> > > 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
> > > problem?
> > > > For instance, can I send a command to the lisp image, and see its
> > > effects
> > > > on the lisp side?
> > >
> > > Firstly, run "netstat -antp" on hal9000 to see if Lisp is listening on
> port
> > > 4005.
> > >
> >
> > 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
> > 104461/lx86cl64
> >
> >
> > >
> > > Secondly, run "netstat -anop tcp" on the Windows 10 machine to see if
> ssh
> > > is
> > > listening on port 4005.
> > >
> > >
> > I have Msys2's netstat. On the laptop:
> > > which netstat
> > /c/WINDOWS/system32/netstat
> > /c/Users/mirko/Downloads
> > > netstat -anop tcp | grep :4005
> > TCP 127.0.0.1:4005 0.0.0.0:0 LISTENING
> 12052
>
> Yes, both netstat outputs look good at that point.
>
>
> > > 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
> > > installed
> > > on Windows 10 by default.)
> > >
> >
> > Outputs of both ssh and telnet on the laptop:
> > > which telnet
> > /usr/bin/telnet
> > /c/Users/mirko/Downloads
> > > telnet localhost 4005
> > Trying ::1...
> > Connected to localhost.
> > Escape character is '^]'.
> > Connection closed by foreign host.
>
> OK, so it is connected to the Windows side at least.
>
> Check that the Slynk server was created with :dont-close t (or set
> slynk:*dont-close* to t before creating it). If dont-close is nil, it will
> only accept one connection, which makes debugging difficult.
>
> Then restart the log in to hal9000 with -v option to ssh to make it print
> debug
> information:
>
> ssh -v -L4005:localhost:4005 mirko at hal9000
>
> and try the telnet again to see what is happening at the Linux end.
>
> __Martin
>
Here is the test log. Telnet and ssh debug are at the bottom.
1 Start slynk with :dont-close t
Modified startup script:
(let ((port 4005))
(slynk:create-server :port port :dont-close t)
(format t "~% Created SLYNK server on port ~a" port))
(setf slynk:*use-dedicated-output-stream* nil)
2 Started tunnel with verbose option, -v switch
$ ssh -v -L4005:hal9000:4005 mirko at hal9000
3 Telnet on laptop side to laptop port 4005
@laptop> telnet localhost 4005
Trying ::1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.
4 SSH debug output
@hal9000> debug1: Connection to port 4005 forwarding to hal9000 port
4005 requested.
debug1: channel 3: new [direct-tcpip]
channel 3: open failed: connect failed: Connection refused
debug1: channel 3: free: direct-tcpip: listening port 4005 for hal9000
port 4005, connect from ::1 port 64100 to ::1 port 4005, nchannels 4
Thanks,
Mirko
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