Basic procedures on Bridge

Information about management procedures on Bridge

Usage

Bridge is provided as a gateway to access the Agustina system. Its purpose is to act as a proxy for connecting from machines that do not have a fixed IP address¹ that can be added to the firewall (working from different centers, ISPs that do not provide that functionality, etc.).
Bridge is not intended to be used as a workspace or storage system, so the user disk quota is minimal (5 MB), but sufficient to log in or copy a public key to allow easier access.

If you need an account, request one by emailing agustina@bifi.es and include "Bridge account request" in the subject, explaining your situation.

Step-by-step connection

First, check that you can access Bridge and that your password is up to date:

ssh <username>@bridge.bifi.unizar.es

If you cannot log in to Bridge, do not have a Bridge account, or do not know your username and/or password, send an email to agustina@bifi.es to obtain the necessary information.

If you have an Agustina account, you can access it via Bridge in a single step with:

ssh -X -J <username>@bridge.bifi.unizar.es <username>@agustina.bifi.unizar.es

You will be prompted for the Bridge and Agustina passwords.

If you encounter problems related to rsa/dss, for example:

Unable to negotiate with UNKNOWN port 65535: no matching host key type found. Their offer: ssh-rsa,ssh-dss

add the following option to the command:

-oHostKeyAlgorithms=ssh-rsa,ssh-dss

resulting in the command:

ssh -oHostKeyAlgorithms=ssh-rsa,ssh-dss -X -J <username>@bridge.bifi.unizar.es <username>@agustina.bifi.unizar.es

Copying files through Bridge

You can copy files from Agustina to your local machine via Bridge using a command like:

scp -oHostKeyAlgorithms=ssh-rsa,ssh-dss -oProxyCommand="ssh -W %h:%p <bridge_user>@bridge.bifi.unizar.es" <agustina_user>@agustina.bifi.unizar.es:/path/to/source/file /path/to/destination

To copy from your local machine to the Agustina scratch directory:

scp -oHostKeyAlgorithms=ssh-rsa,ssh-dss -oProxyCommand="ssh -W %h:%p <bridge_user>@bridge.bifi.unizar.es" local_file_to_copy <agustina_user>@agustina.bifi.unizar.es:/fs/agustina/<username>

If you experience compatibility issues between SSH versions, you can use the -O modifier:

scp -O -oHostKeyAlgorithms=ssh-rsa,ssh-dss -oProxyCommand="ssh -W %h:%p <bridge_user>@bridge.bifi.unizar.es" local_file_to_copy <agustina_user>@agustina.bifi.unizar.es:/fs/agustina/<username>