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Can I connect to one computer cluster through another in Fetch? (4 posts)

  • Started 4 years ago by Ron
  • Latest reply 4 years ago from Scott McGuire
  • Ron Member

    Hi,

    I'm a graduate student and I use Fetch to connect to computing clusters via SFTP. Most of the clusters are only accessible through Internet 2 networks. There is one big cluster though that can be accessed through any network.

    The problem is that I can't access most of the clusters directly when away from the university. What I can do is ssh into the big cluster through terminal and then, once connected, ssh into any of the other clusters. If I do that though can't use all the nice Fetch features I've grown accustomed to.

    Is it possible in Fetch, perhaps through scripting, to first connect to the big cluster and then from there to use SFTP to access the other ones? If so, it would be great.

    Thanks in advance for the help.

    Cheers,
    Ron

    Posted 4 years ago #

  • Scott McGuire Administrator

    Hi Ron,

    I apologize for the delay in replying to you - I was consulting with my colleagues about your question.

    You can probably solve this problem by setting up SSH tunneling. You'll need to use the command-line, and unfortunately you'll need to set up the tunnel again every time after your network is closed down (such as, your Mac goes to sleep, is restarted, or you change a network setting).

    The command to type in Terminal to set up the SSH tunnel is:

    ssh -f username@external-host -L 4222:internal-host:22 -N

    where external-host is the hostname of a server in the cluster that you can connect to directly, internal-host is the hostname of a server in one of the clusters you cannot reach directly, and the username should be your username for the server you can connect to directly. You will be prompted for your password for the directly accessible server, if necessary.

    Then to connect to the not-directly-accessible server with Fetch after running this command, you should enter "localhost" (without quotes) in the Hostname field, enter the username and password for the not-directly-accessible server, choose SFTP from the Connect using menu, and enter "4222" (without quotes) in the Port field.

    Note that this setup will only work with one server in the clusters that you cannot reach directly. If you need to connect to more than one, let us know and we can advise about how to do that.

    Please let us know how it goes or if you have any questions, and we'll try to help out.

    Thanks,

    Scott McGuire
    Fetch Softworks

    Posted 4 years ago #

  • Ron Member

    Thanks, Scott! That worked like a charm.

    Cheers,
    Ron

    Posted 4 years ago #

  • Scott McGuire Administrator

    Hi Ron,

    You're welcome - we're glad to hear that worked for you.

    Best,

    Scott McGuire
    Fetch Softworks

    Posted 4 years ago #

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