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Quick question - I run two linux boxes, one my own desktop and the other my VPS. For security reasons on the VPS end I opted for socket connections to MySQL (/var/run/mysqld/mysql.sock). I know I can tunnel like this: ssh -L 3307:127.0.0.1:3306 user@site.com if I set up the remote sql server to listen on some port, but what I want to know is can I do something like: ssh -L /path/to/myremotesqlserver.sock:/var/run/mysqld/mysql.sock thereby tunnelling two sockets, as opposed to two ports?

A perfectly acceptable solution would also be to forward a local port to the remote socket file, but where possible I'm trying not to have tcp servers running on the remote box.

(and yes, I know tcp would be easier).

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If the reason you don't want to use TCP on the mySQL box is because of security concerns (i.e. remote attacks, etc) you can ofcourse either firewall it, and if that is not good enough, make mySQL only listen to 127.0.0.1 for its TCP connections, then you can tunnel through SSH easily. If not, I support the socat solution below. –  Mattias Ahnberg Feb 22 '12 at 23:30

5 Answers 5

up vote 2 down vote accepted

No, you cannot. At least, I cannot plausibly think of a method to use the MySQL socket file remotely. Your only options involve TCP/IP sockets or running a client local to the server either via SSH or something like phpMyAdmin.

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Hmmm, what a shame. Ok thanks. I'll leave this open for the moment to see if anyone does know of a way. +1. –  Ninefingers Mar 30 '10 at 18:32

i haven't done this, but i would try with socat. maybe something like:

ssh xxx@yyy.zzz -L 9999:localhost:9999 "socat TCP-LISTEN:localhost:9999 UNIX-CONNECT:/var/run/mysqld/mysql.sock"
socat UNIX-LISTEN:/path/to/local/socket TCP:localhost:9999

again, i have never done anything like this.

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I'll give it a go and let you know how it goes. I've been using the tcp-based implementation. –  Ninefingers Mar 30 '10 at 20:18
    
I can't get it to work at the moment but +1 anyway for the idea, I like it. I'll let you know if I fix it. –  Ninefingers Mar 30 '10 at 20:32
    
+1 looks like a useful utility. –  Warner Mar 30 '10 at 20:43

Forward a local socket on demand

  • Setup SSH public key authentication
  • Install socat at both ends
  • create a directory locally for your sockets, inaccessible to other users.
export SOCKET_DIR=~/.remote-sockets
socat "UNIX-LISTEN:$SOCKET_DIR/mysqld.sock,reuseaddr,fork" \
EXEC:'ssh user@server socat STDIO UNIX-CONNECT\:/var/run/mysqld/mysqld.sock'

then

mysql -S $SOCKET_DIR/mysqld.sock -u mysqluser -p

stolen from forwarding unix domain sockets with ssh and socat

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Elaborating on Javier's answer, this works for me:

ssh -f xxx@yyy.zzz -L 9999:localhost:9999 "socat TCP-LISTEN:9999,fork,bind=localhost UNIX-CONNECT:/var/run/mysqld/mysql.sock"

You need fork in order to be able to connect multiple times without socat dying once you close the first connection. Also, the way socat lets you specify an address to bind to is through the bind option, not as an address before the port.

After this, just connect to localhost:9999 normally as you would. Then to teardown the tunnel:

ssh -f xxx@yyy.zzz "killall socat"

(or something similar, you can do more elaborate things that involve keeping socat's PID)

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Yes, you can using socat.

First do the TCP tunnel with SSH. Then use socat like this:

socat unix-listen:/var/run/mysqld/mysqld.sock,fork,unlink-early tcp:127.0.0.1:3306

Then give permissions to new created socket (chmod 777 may be)

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