0

I currently have the problem that I don't know whether a firewall has access to the query string of a URL, for example:

www.example.com/muster.html?Name=Max+Mustermann&Ort=Musterstadt&PLZ=1234

If it checks the URL, does it only see www.examle.com or the rest of the URL as well?

The reason behind my question is that I don't want the metadata that I send in the URL as a query string to be blocked by the firewall.

Yannis
  • 1,682
  • 7
  • 27
  • 45
SimmensK
  • 17
  • 7

2 Answers2

4

Depends on the layer your firewall operates.

Wiki https://en.wikipedia.org/wiki/Firewall_(computing)#Network_layer_or_packet_filters:

Network layer firewalls, also called packet filters, operate at a relatively low level of the TCP/IP protocol stack.

They basically check IP address and port.

Many modern products also work at application layer and with technologies like content filters - they can see the entire request - including the request parameters (but they would also see your post body).

By using HTTPS your query parameters are encrypted (check Is an HTTPS query string secure?). In this case the firewall can't access these parameters. In practice there are e.g. corporate proxy scenarios where even HTTPS requests are intercepted, checked and re-signed by a trusted certificate. In these scenarios content filters can even see encrypted query parameters/ request information.

Hope that helps!

Jonas
  • 494
  • 4
  • 7
  • 2
    What Jonas mentioned at the end is called `SSL inspection`. Web gateways like McAfee provide such a functionality to scan encrypted traffic. See http://www.webtorials.com/main/resource/papers/McAfee/paper2/inspecting-encrypted-web-traffic.pdf – René Link Jan 16 '18 at 12:05
-1

A Firewall is here to protect computer, he can check url and of course the data passed through URL.

Léo R.
  • 2,620
  • 1
  • 10
  • 22