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General information

Web-Filter (Proxy) (EN)


The IT Center operates a powerful web filter infrastructure (proxy) which, in addition to virus scanning, also classifies websites based on their reputation and prevents access to pages with a poor score (similar to the procedure used for spam filters). A reputation score on a scale from -10.0 to +10.0 is used for websites. From a score of -6.1 the page is blocked.

Reputation scores can be viewed on

The purpose here is to prevent malware from being downloaded again and again at an early stage.

Currently, the web traffic of VPN, eduroam, RWTH-guests, student hostels and some larger institutions is routed via these proxies via the Web Cache Communication Protocol (WCCP) (transparent proxy).

If an important page is not accessible, please follow the instructions in the proxy server message.

There are currently two variants available:

  • With anonymization of the client IP address, i.e. only the IP address of the web proxy is known to the contacted web server.
  • Passed client IP address (spoofing), i.e. the Web server sees the client IP address.

The second option can be useful for services that insist on unique client IPs, but can only be implemented via WCCP.


The IT Center stores URLs and IP addresses of client systems for a period of seven days for troubleshooting and investigating security incidents only. The basis for this is the RWTH network regulations, ยง3, para. 3.