The Domain Name System (DNS) is on the one hand a hierarchical system for naming TCP/IP computers, on the other hand it is to be understood as a distributed online database system which allows the resolution of a readable machine name (host name) into an IP address or a mail exchanger or mail server address and vice versa. The DNS servers connected in the Internet enable the local IP address allocation or administration (e.g. in the TUnet) by the implementation of hierarchically arranged name ranges.

Each TCP/IP host connected to TUnet receives a unique IP address (Internet Protocol Address) as well as an Internet domain name in the domain of TU Wien (ending or in a subdomain of the domain of TU Wien assigned to the institute. This address or name coordination for TUnet is carried out by IT Solutions ( of the TU Wien. This host must be registered in the TUnet database.

In order to be able to set appropriate security measures (e.g. firewall, bastion computer for mail, ...), it is necessary that between

  • internal name servers (which can only be accessed from computers at the TU Wien) that display the TUnet view for TU computers, and
  • external name servers (also accessible from outside the TU Wien), which publish the view for computers outside the TU Wien (e.g. redirection of mails to the bastion computer to block viruses or mark SPAMs)

is distinguished.

Therefore, in addition to the two internal name servers, there are also two external name servers to which all official pointers (in the domains above the TU Wien and reverse domains) refer. This means that only the external name servers in the official tables are known nationally and internationally.

Internal Domain Name Servers

(only for computers within the TU Wien): IP address: IP address:

Depending on the IP address (128.130.* or 128.131.*) of the computer in question, the name server in the same network should be configured first and the other one second.

These two domain name servers should be used for address resolution on computers connected to the TUnet. If you have platform-specific questions regarding the configuration of the DNS on your computer, please contact our Service Center!


Computers without an IPv4 address can use the following IPv6 nameserver addresses: IPv6 address: 2001:629:1001:1::53 IPv6 Address: 2001:629:1001:2::53

External Domain Name Server

Two external domain name servers are installed in the DMZ between TUnet and the Internet: IP address: IP Address:

However, these servers should never be configured as name servers (the name servers of the respective provider via which the computer is connected are there for this purpose). The external name servers are only intended for requests from other name servers.

For security reasons it is not possible to access computers inside the TU Wien from outside the TU Wien using the Domain Name Service Protocol (Port 53).

("foreign domains": do not end with, but refer to an IP address in the TUnet)

The use of external domains for computers at the TU Wien requires the approval of IT Solutions.
For this permission, please send an email to, which also contains a proof for which the foreign domain is required for the TU Wien affine task.

Domains for private addressing (e.g. for email services) are not permitted!

Computers in such a foreign domain must nevertheless be entered with the main name in the regular subdomain of the institute within the and must also report with this name (e.g. with SMTP in the HELO greeting or with FTP in the greeting for connection establishment).

Service Center

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© TU Wien

Ticketsystem Online Portal, opens an external URL in a new window
Hotline 01 588 01 42002
1040 Wien, Operngasse 11, EG

The Service Center can be reached from 8 a.m. to 4 p.m.

Compliance with the currently applicable COVID-19 security regulations is assumed.

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