6.2.3 Version 4.6.0

4.6.0 MetaDefender ICAP Server release

14 June, 2019

MetaDefender ICAP Server 4.6.0 is a feature release focused on improvements.

New & improved

Permissive parsing to accept space in header names

When Settings > Global Settings / ENABLE PERMISSIVE PARSING is enabled, MetaDefender ICAP Server will accept header names that contain a trailing space.


The following example shows a header that contains a trailing space (note the space between the header name and the colon):

Access-Control-Allow-Origin : * 

By the standards, header names must not contain a trailing space, the colon must follow immediately. Some customers, however, experienced this issue, and received Invalid character found in HTTP response header name errors in the logs.

Support further placeholder tokens in the block page

In customized block pages it is now possible to show information about:

  • The URL parsed from the original request,

  • Address of the client from whom the request originated,

  • Name of the server the ICAP Server is running on,

  • Date & time of the arrival of the request to the ICAP Server,

  • Names of the files that were blocked,

  • Media types for files that were blocked,

  • Violations for blocked files (e.g. infection, size limit).

Not in the default block page

These new placeholder tokens are not used in the default block page, but are available for a custom block page.

For further details see 3.8 Customizing the block page.

Rules to support filtering by the ICAP client (proxy)

Under Policy > Security Rules / add/modify / REQUEST FILTERS MetaDefender ICAP Server now supports filtering requests by the IP address of the ICAP client (e.g. proxy).

This filter - for example - helps to assign specific rules to traffic that arrives from specific ICAP clients (proxies).


For further details see the ICAP client IP conditions section in 4.2 Security rules.