Introduction

The article Remote Access will show you possible solutions to remotely access a managed client or your data inside the D-ITET networks from the selfmanaged client network or from devices outside the ETH network. It will cover the following topics:

Remote access and network restrictions

Remote access possibilities depend on firewall restrictions between the remote client and the target network. The networks are segmented into virtual private zones (VPZ). Each of these zones corresponds to a certain network security level profile and contains one or more subnets being protected by the appropriate zone firewall. Traffic between subnets belonging to the same VPZ does not pass the zone firewall and thus there are no traffic flow restrictions (no subnets or service ports blocked). The relevant VPZ's for D-ITET are:

Enabled remote access protocols

The following table shows protocols which are relevant for remote access:

protocol

protocol long

usage

ICMP

Internet Control Message Protocol

protocol used by ping connection test

SSH

Secure Shell

encrypted remote terminal session

HTTP/ HTTPS

[Secure] Hypertext Transfer Protocol

web server access protocol

RDP

Remote Desktop Protocol

remote desktop sessions on windows targets

VNC

Virtual Network Computing

remote desktop sessions on linux targets

SMB/ CIFS

Server Message Block/ Common Internet Filesystem

Microsoft network file sharing protocol

NFS

Network File System

Linux network file sharing protocol

IMAP

Internet Message Access Protocol

access to mailboxes on server

SMTP

Simple Message Transfer Protocol

sending messages to server

Remote access map of allowed traffic

The following table shows the allowed traffic flows for remote access related services:

Client source network -> Remote destination network

ICMP

SSH

HTTP/ HTTPS

RDP

VNC

SMB/ CIFS

NFS¹

IMAP/ SMTP

internet -> itet-isg

(./)

{X}

{X}

{X}

{X}

{X}

{X}

( (./)

internet -> itet-staff

(./)

{X}

{X}

{X}

{X}

{X}

{X}

{X}

vpn network -> itet-isg

(./)

(./)

(./)

(./)

(./)

(./)

{X}

(./)

vpn network -> itet-staff

(./)

(./)

(./)

(./)

(./)

(./)

{X}

(./)

itet-staff -> itet-isg

(./)

(./)

(./)

(./)

(./)

(./)

{X}

(./)

itet-isg -> itet-staff

(./)

(./)

(./)

(./)

(./)

(./)

{X}

(./)

From the zones itet-isg and itet-staff to the internet the ip transport protocols TCP/ UDP are generally enabled. Every machine inside can initiate a connection to an arbitrary server port in the internet.

Mailbox Access

Web Access (Roundcube)

You can access your inbox and your mail folders with a web browser on any client with internet connectivity. Our web server with the Roundcube software can be reached under https://email.ee.ethz.ch.

IMAP/ SMTP Access

You can also access your mail with any IMAP/ SMTP based mail client software ( Thunderbird, Outlook, Smartphone Mail Programs, Windows 10 Mail, ......) over the internet. IMAP/ SMTP access to our mail servers is enabled for the internet. Detailed information is available in the Email overview page.

SSH - remote terminal session

In the Linux world remote terminals are widely used. The secure shell ssh allows secure (i.e. encrypted connection) remote terminal sessions. To establish such sessions, you will need an SSH client application. Under Linux and Mac OSX, the program is called ssh and is usually provided by the basic installation of the operating system. Under MS Windows, a 3rd party manufacturer application like PuTTY (http://www.chiark.greenend.org.uk/~sgtatham/putty), X-Win32, or the Cygwin SSH client must be installed separately.

Establishing a remote terminal session

SSH details

The ssh protocol has some integrated features like

With these features ssh also offers solutions to additional tasks which are covered in the following chapters.

The host login.ee.ethz.ch might be used to log in to the D-ITET network from anywhere (all D-ITET users are allowed to log in there). Use this host only as a starting point (i.e. to establish further connections to other D-ITET-internal computers from there), but do not execute processes that will consume a lot of CPU resources (e.g. do not run Matlab/ compute jobs on this machine!).

For advanced users: If you want to make sure a managed ISG.EE Linux computer you intend to access with ssh is in fact the machine you are expecting (and not a modified/ hacked one; e.g. with man-in-the-middle-attack), you can verify its hostkey. How that works is described on this website: https://computing.ee.ethz.ch/SshFingerprints

Remote Desktop Session

Windows Remote Desktop

To access your Windows computer remotely, please read Windows Remote Desktop Services.

X11VNC

x11vnc can be used to connect to a desktop session running on the physical display of a host. Please see the X11VNC HOWTO for further details. In case you have no running session on the physical display and need to login graphically, please contact support and provide the name of the host you need to access.

VNC

VNC is the preferred solution for remote desktop sessions on Linux machines. Please read the VNC article for more details.

File Transfer

HTTP download

The HTTP download is a simple solution to transfer a data file to an external user. On the client side no additional software is needed, a web browser is sufficient.

Here are the sample commands to provide a data file for download with a required authorization in your personal web page:

> mkdir /home/pmuster/public_html/transfer
> cp /scratch/pmuster/datafile /home/pmuster/public_html/transfer/
> htpasswd -s -c /home/pmuster/public_html/.htpasswd download

Create a file .htaccess in the download folder /home/pmuster/public_html/transfer with content:

AuthUserFile "/home/pmuster/public_html/.htpasswd"
AuthName "Downloads"
AuthType Basic
Require user download

Under the address http://people.ee.ethz.ch/~pmuster/transfer the file can now be downloaded with user download and the password set with the htpasswd command.

Linux scp

Between two Linux machines you can transfer a file with the ssh-integrated secure file copy (scp). The command is:

user@home> scp <path-to-datafile> <user>@<hostname>:<path-to-target directory>

With the command

user@home> scp document.pdf pmuster@login.ee.ethz.ch:Documents/

the file document.pdf on your linux machine is copied in the Documents subdirectory in your home at D-ITET.

Windows WinSCP/ FileZilla

Windows has no SSH integrated, so you must use an additional software. The popular programs WinSCP (https://winscp.net) and FileZilla (https://filezilla-project.org) are the preferred choice. FileZilla is also available for the linux platform and is already installed on our managed linux clients.

ID polybox - Own Cloud Storage

ID provides 50 GB storage to every ETH member https://www.ethz.ch/services/en/it-services/catalogue/storage/polybox.html. The polybox client software is available for different plattforms and synchronizes a local storage on the client with the owncloud server storage. If the client software is installed on two machines you can therefore transfer data between the two machines with the polybox/ownclound client.

SWITCHfilesender

SWITCH offers a service for the exchange of big sized data which can not be send by mail called Filesender (https://www.switch.ch/services/filesender). It's a good solution for sporadic transfers of big sized data (up to 300GB) to a site where no IAM account can be used. The uploaded data will be cleaned automatically after a pre-defined time.

Cifex

/!\ This services will be decommissioned at the end of 2021

Use Polybox and SWITCHFilesender instead.

Network File System Access

NFS access

Because NFS is not enabled between the internal networks nor to the internet it has no significance in remote access solutions. NFS is only used by ISG managed linux clients to access user and project homes on servers and dedicated storage systems of ID and ITET by Linux automount tables.

SMB/ CIFS access

This Microsoft network file sharing protocol has a user based authentication and therefore has a great significance for accessing data resources not only on windows file servers. Linux servers are also providing SMB/ CIFS access with use of the samba software suite, an emulation of the windows file sharing protocol for Linux file servers.

More information how to access your data you find under:

  1. If possible use a VPN client connection to the ETH network to better distribute the access (1)

RemoteAccess (last edited 2021-09-20 15:30:47 by mreimers)