| Both sides previous revision Previous revision Next revision | Previous revision |
| en:praktikum:zugang [2024/12/05 11:48] – rhainich | en:praktikum:zugang [2025/10/30 15:40] (current) – [Alternative: Xpra] rhainich |
|---|
| ====== Access to the laboratory computer ====== | ====== Access to the laboratory computer ====== |
| |
| <WRAP center round important 60%> | <WRAP center round info 60%> |
| ZIM has blocked direct SSH access from outside the university network throughout the university. Why they do this for the most secure protocol on the market is, to put it mildly, completely incomprehensible to us. At the moment you have to log into the university network via VPN before you can access the data reduction computer. The [[https://www.uni-potsdam.de/en/zim/angebote-loesungen/vpn | ZIM]] explains how to set up the VPN. Unfortunately the instructions are only available in German. If you have any questions about the VPN, please contact ZIM directly. | From December 2024, to access the data reduction computer via SSH, you must first log in via VPN. The [[https://www.uni-potsdam.de/en/zim/angebote-loesungen/vpn | ZIM]] explains how to set up the VPN. Unfortunately the instructions are only available in German. If you have any questions about the VPN, please contact ZIM directly. |
| </WRAP> | </WRAP> |
| |
| Alternatively you can log in with [[https://www.xpra.org/|Xpra]], which also communicates via //SSH//, but allows you to work with graphical output even with a poor internet connection. //Xpra// usually has to be installed from the package sources first. Once this is done, the following command establishes a connection to the laboratory computer | Alternatively you can log in with [[https://www.xpra.org/|Xpra]], which also communicates via //SSH//, but allows you to work with graphical output even with a poor internet connection. //Xpra// usually has to be installed from the package sources first. Once this is done, the following command establishes a connection to the laboratory computer |
| |
| xpra start ssh:alpha@columba.astro.physik.uni-potsdam.de --ssh=ssh | xpra seamless ssh:alpha@columba.astro.physik.uni-potsdam.de --start=konsole |
| |
| The command is not very different from the one above, except that here the beginning and the end are slightly different. **alpha** has to be replaced by the group name here as well. If the connection has been established successfully, a //Xpra// icon or menu usually appears on the desktop (under Ubuntu it can be found in the upper right corner next to the network/volume/battery indicator). This menu can be used to configure //Xpra// as well as, via the menu item ''Start'', to start programs directly on the laboratory computer. //Xpra// has the nice advantage that the windows integrate seamlessly into the local system. | The command is not very different from the one above, except that here the beginning and the end are slightly different. **alpha** has to be replaced by the group name here as well. If the connection has been established successfully, a //Xpra// icon or menu usually appears on the desktop (under Ubuntu it can be found in the upper right corner next to the network/volume/battery indicator). This menu can be used to configure //Xpra// as well as, via the menu item ''Start'', to start programs directly on the laboratory computer. //Xpra// has the nice advantage that the windows integrate seamlessly into the local system. |
| |
| Furthermore it offers the possibility to disconnect from the //Xpra// session without ending it by using the menu button ''Disconnect''. This allows you to interrupt the session at any point and continue it later. All that is needed is the following console command: | Furthermore it offers the possibility to disconnect from the //Xpra// session without ending it by typing ''xpra detach'' in a Terminal. This allows you to interrupt the session at any point and continue it later. All that is needed is the following console command: |
| |
| xpra attach ssh:alpha@columba.astro.physik.uni-potsdam.de --ssh=ssh | xpra attach ssh:alpha@columba.astro.physik.uni-potsdam.de |
| |
| The //Xpra// session is terminated with: | The //Xpra// session is terminated with: |