Why is the vpn.ntua.gr service of use to me?
Because it allows you to connect to the N.T.U.A. network from wherever you are. When connected to vpn.ntua.gr you can have access to the N.T.U.A. library, send e-mails without any alterations in your PC or have access to your local laboratory or subnetwork. In the case that you are away on a trip or you connect via a different ISP than your houses, you may use vpn.ntua.gr in order to access these services.
Where can I use this service from?
From anywhere you have access to the internet. The connection with N.T.U.A. takes place via a virtual connection.
Is there a cost when I use VPN?
There is no cost when you use the service from N.T.U.A. Nevertheless you will have to have access to the internet, probably from a telephone company. The cost of the internet connection has no correlation to the VPN service of N.T.U.A.
Is there a time limit, like in dialup;
No! There are no time limitations or volume limitations in vpn.ntua.gr.
Can I pass it on to my friends?
No! Like any other service provided by N.T.U.A. this account is strictly private and sharing it endangers your security. In the case of use by a third party, the Network Center has the right to deny you access for any time period.
Can I use via VPN the network neighbourhood towards my PC within N.T.U.A.?
Yes! For your convenience you are allowed to use this protocol.
It is not possible to connect.
Confirm that the application is properly installed, that no security application (firewall) interrupts the communication and that you have the latest edition of the program offered by the Network Center. If you are trying using udp, try again using tcp. If you still cannot connect, e-mail us or call our technical support office at 210-772-1861.
What username and password do I use?
The same ones that you use for all the services, like dialup, my.ntua.gr, ntua-wifi etc.
The service does not work even though the connection is successful.
A cause for this problem is often the existence of a safety application like firewall programs which don’t allow any data transfer over the network equipment Tap. You will have to create access via the program to the openvpn as well as the network equipment Tap. If you are using Windows, check whether the DHCP Client service of Windows is activated.
I have completed the installation, but I don’t know what to use, udp or tcp.
Always use udp since it clearly has a better performance. If you discover that you can’t connect to udp, then try to use tcp.
I am getting the message "All TAP-Win32 adapters on this system are currently in use". What is wrong?
This message might be due to a series of problems. Most common being:
1. Attempt to execute multiple openvpn simultaneously. For example, you are connected with udp protocol and you are trying to reconnect with tcp.
2. The ο tap-win32 adapter has been disabled. This network equipment is necessary to be on in order for the service to work. You may activate it, in case you have deactivated it, from the network connections on the control panel. If it is not there, then the network equipment is not installed, so you will have to install it. The installment offered by the network center preselects this network equipment.
3. In the case of Μιcrosoft Windows as well as in other operative systems you will need administrative rights in order to have access in this network equipment.
I am operating on Windows 98 and even though VPN is installed it doesn’t open and presents a message of error.
The editions of Windows 95, Windows 98 και Windows Me are no longer supported by their software developing company. They also don’t support the VPN application. We would recommend to upgrade your software soon.
How can I set my browser to connect to N.T.U.A. through VPN?
Your browser doesn’t need any special setting. You just need to download and execute the VPN application offered from the Network Center every time you want to connect via a private network to N.T.U.A.
I can’t find ntua-udp or ntua-tcp and therefore I can’t connect to openvpn-gui. In the past I was using openvpn provided by another organization. What should I do?
If in the past you were using openvpn from another organization, probably the openvpn-gui setting are wrong. You may try to apply the following file: openvpn-gui-default-settings.reg
I am presented with an error: "VERIFY ERROR: depth=2, error=certificate is not yet valid: /C=GR/O=NTUA/CN=NTUA_ROOT_CA".
Your time and date setting on your computer is probably wrong. Please correct it and retry.
On Mac OS X Mountain Lion I detect that the connection can’t be established and at the same time the tunnelblick icon of the menu bar blinks constantly and it doesn’t stop.
It is possible that you are using an older edition of the tunnelblick software. Since January the 4th 2013 the available software on the Network Centre’s page is based on tunnelblick 3.3beta20 which fixes this problem.
For more information you may contact the Network Center’s Help-Desk Monday to Friday 9:00 a.m. – 17:00 p.m. Tel: 210 – 772 1861, fax 210 – 772 186 or directly the Network Center building. You can also e-mail the supervisor: firstname.lastname@example.org.