Can Microsoft ISA server and Guardian co-exist on the same network; if so what is the preferred setup?

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How to set up Smoothwall's web filter with a Microsoft Internet Security and Acceleration (ISA) server.


Can Microsoft ISA server and Guardian co-exist on the same network and what would be the preferred setup in such cases?


There are no inherent problems in running both the ISA server and the Guardian web filter on the same network.

Smoothwall recommends that:

  • Web clients use Guardian
  • Guardian is allowed web access through the ISA server without going through the ISA as a proxy.

This allows Guardian to use the authentication options as intended, and the ISA server can be used to ensure no clients access the web without going through Guardian first.

This setup also allows the ISA server to permit specific clients web access without going through Guardian, which may be needed for web applications that have difficulties in working through a proxy server.

Tip: Check if the ISA server is publishing proxy settings to the network, and if so, change the proxy setting to be the Guardian IP address or hostname instead.

Tip: If the ISA server has been set up to limit the number of connections going through it from any one single IP address, review the connection numbers and adjust it to allow for the fact that all your users will now be browsing through Guardian thus increasing the incoming connection number from the Guardian IP address.


Last updated: Author: Contributions by:
06 September 2016   Tanja