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Philipp Claßen
Asked: 2013-08-17 01:05:59 +0800 CST

Keeping ssh connections open on Windows?

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I know that on Unix Systems, you can keep an ssh connection open.

Step 1: Create a ssh configuration, for example:

 Host <some.host.name>
 ControlPath ~/.ssh/master-%r@%h:%p
 ControlPersist yes

Step 2: Start ssh with the -M parameter.

Is there something equivalent under Windows to reuse ssh connections? Maybe I looked at the wrong places, but I didn't find any good links on this topic.

(I tried my approach from above in a MingGW environment (using MingGW's ssh client). In real Unix system, it should have created a special socket file in ~/.ssh, but that functionality does not seem to be supported by MingGW.)

windows

3 Answers

  1. Best Answer

    You need to use openssh for windows, either through cygwin, or this port: http://miked.ict.rave.ac.uk/display/sshwindows/OpenSSH+for+Windows

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  2. You are talking about two different things:

    Your subject indicates keeping connections open indefinitely, where my answer would be: If you are using puTTY, then you can set a keepalive in the configuration of a session: Configuration => Connection: Sending of null packets to keep session active Seconds between keepalives (0 to turn off)

    Your text indicates connection sharing. No idea for puTTY with that.

    Kind regards, Viktor Zacek

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  3. Bug 1278 - CYGWIN controlMaster connections don't work. describes use of ControlMaster/ControlPersist as partially implemented under Cygwin as of December, 2016, but with a qualification that it works only for remote commands and not for connections that require a pseudo terminal.

    While this answer was not confirmed under Cygwin, per se, it was validated as true for MSYS2 (based on Cygwin). openssh under MSYS2 supports ControlMaster/ControlPersist connections for remote commands, but not for interactive sessions.

    $ cygcheck -V | head -3
cygcheck (msys) 3.0.7
System Checker for Msys
Copyright (C) 1998 - 2019 Cygwin Authors

$ ssh -V
OpenSSH_8.1p1, OpenSSL 1.1.1d  10 Sep 2019

$ pacman -Qi openssh
Name            : openssh
Version         : 8.1p1-1
Description     : Free version of the SSH connectivity tools
Architecture    : i686
URL             : https://www.openssh.com/portable.html
Licenses        : custom:BSD
Groups          : net-utils
Provides        : None
Depends On      : heimdal  libedit  libcrypt  openssl
Optional Deps   : None
Required By     : sshpass
Optional For    : None
Conflicts With  : None
Replaces        : None
Installed Size  : 4.55 MiB
Packager        : Alexey Pavlov <[email protected]>
Build Date      : Mon, Oct 14, 2019 1:12:28 AM
Install Date    : Thu, Oct 24, 2019 8:38:48 PM
Install Reason  : Explicitly installed
Install Script  : No
Validated By    : Signature

    The following errors occur when running ssh without a remote command specified:

    mm_send_fd: sendmsg(2): Broken pipe
mux_client_request_session: send fds failed

    With remote commands specified, the errors do not occur.

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