Filtering HTTP headers and HTML tags by DeleGate

Yutaka Sato
October 30, 2001

Easy and efficient ways of filtering HTTP headers and HTML tags have been introduced in DeleGate of version 7.6.1. Undesirable headers from a security consideration, "Referer" for example, can be stopped to be forwarded by a parameter like this:

Unwelcom HTML tags, "SCRIPT" for example, can be disabled with a parameter like this: Using external filters just to do filtering like above is no longer recommended because of its inefficiency.

For people who have no experience with DeleGate

You can use DeleGate as a HTTP proxy for filtering like above with a command line like this:

delegated -P8080 SERVER=http HTTPCONF=kill-qhead:Referer HTTPCONF=kill-tag:SCRIPT

[excerpt from Manual.htm#HTTPCONF (DeleGate/7.7.1)] 
HTTPCONF parameter  ==  what:conf
    kill-[qr]head: listOfHeaders
    erase header fields listed in listOfHeaders before forwarding a request/response message to server/client. "kill-qhead" is applied only to request message to server and "kill-rhead" is applied only to response message to client.

    Example:

      HTTPCONF=kill-qhead:Referer
      HTTPCONF=kill-qhead:If-*,Accept-*
      HTTPCONF=kill-rhead:Set-Cookie

    kill-tag: listOfTags
    disable a tag listed in listOfTags when it it used in a text/html response from a server.

    Example:

      HTTPCONF=kill-tag:SCRIPT,APPLET