Speed Up Multiple SSH Connections to the Same Server
If you run a lot of terminal tabs or scripts that all need to make OpenSSH connections to the same server, you can speed them all up with multiplexing: making the first one act as the master and letting the others share its TCP connection to the server.
If you don't already have a config file in the .ssh directory in your home directory, create it with permissions 600: readable and writeable only by you.
Then, add these lines:
Host * ControlMaster auto ControlPath ~/.ssh/master-%r@%h:%p
ControlMaster auto tells ssh to try to start a master if none is running, or to use an existing master otherwise. ControlPath is the location of a socket for the ssh processes to communicate among themselves. The %r, %h and %p are replaced with your user name, the host to which you're connecting and the port number—only ssh sessions from the same user to the same host on the same port can or should share a TCP connection, so each group of multiplexed ssh processes needs a separate socket.
To make sure it worked, start one ssh session and keep it running. Then, in another window, open another connection with the -v option:
~$ ssh -v example.com echo "hi"
And, instead of the long verbose messages of a normal ssh session, you'll see a few lines, ending
debug1: auto-mux: Trying existing master hi
If you have to connect to an old ssh implementation that doesn't support multiplexed connections, you can make a separate Host section:
Host antique.example.com ControlMaster no
For more info, see man ssh and man ssh_config.
|Raspi-Sump||Dec 16, 2014|
|diff -u: What's New in Kernel Development||Dec 12, 2014|
|Non-Linux FOSS: Don't Type All Those Words!||Dec 10, 2014|
|Computing without a Computer||Dec 08, 2014|
|Autokey: Shorthand for Typists||Dec 04, 2014|
|How Can We Get Business to Care about Freedom, Openness and Interoperability?||Dec 03, 2014|
- Readers' Choice Awards 2014
- diff -u: What's New in Kernel Development
- Cooking with Linux - Serious Cool, Sysadmin Style!
- How Can We Get Business to Care about Freedom, Openness and Interoperability?
- Synchronize Your Life with ownCloud
- Days Between Dates?
- Computing without a Computer
- Non-Linux FOSS: Don't Type All Those Words!
- Autokey: Shorthand for Typists
Editorial Advisory Panel
Thank you to our 2014 Editorial Advisors!
- Jeff Parent
- Brad Baillio
- Nick Baronian
- Steve Case
- Chadalavada Kalyana
- Caleb Cullen
- Keir Davis
- Michael Eager
- Nick Faltys
- Dennis Frey
- Philip Jacob
- Jay Kruizenga
- Steve Marquez
- Dave McAllister
- Craig Oda
- Mike Roberts
- Chris Stark
- Patrick Swartz
- David Lynch
- Alicia Gibb
- Thomas Quinlan
- Carson McDonald
- Kristen Shoemaker
- Charnell Luchich
- James Walker
- Victor Gregorio
- Hari Boukis
- Brian Conner
- David Lane