Firewall

Physics runs a firewall configuration which blocks all incoming connections from both the university and the internet in general.

The following ports are open to the internet on all hosts.

• 22 (ssh) is open to all hosts from everywhere on the internet.

Its possible to poke holes in the firewall to specific hosts in some circumstances, though we require a string business-reason to do so without an alternative.

If you are wanting to connect to a system inside physics from outside, most simple applications can be tunneled over ssh. For example, VNC (remote desktop) can be tunneled by following this guide: Tunneling VNC over SSH with PuTTY. If you need assistance with configuring SSH to support your application, contact us for help.

To make localhost:1234 connect to somehost.physics.umn.edu on port 5510

> ssh -L1234:somehost.physics.umn.edu:5510 myusername@physics.umn.edu 

The guide Tunneling VNC over SSH with PuTTY gives an example of using PuTTY to forward VNC over SSH.

Some applications do not behave properly when used behind a firewall. In this case a proxy can help. Please refer to the following list of workarounds:

Physics users may have trouble transferring data to some FTP servers, if those ftp servers are also behind a firewall. We provide an ftp proxy server to work around this problem. To use it:

• Use your ftp program to connect to ftp-proxy.spa.umn.edu
• At the Name prompt, enter username@hostname where hostname is the remote site you want to connect to, and username is the username at the remote site.
• At the Password prompt, enter your remote site password.

Example:

$ ftp ftp-proxy.spa.umn.edu
Connected to dunnotar.spa.umn.edu.
220 FTP proxy (v0.13.5) ready
Name (ftp-proxy.spa.umn.edu:root): anonymous@some-ftp.site.edu
Password:
230 Login successful.
ftp>