Category Archives: Komodia’s products

DNS server filtering Delphi

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When you need to filter a DNS request, there are number of ways to do it:

  • Add an entry to the hosts file.
  • Intercept the UDP data and modify it.
  • Use NSP (Named Space Provider)
  • Use detour to catch the DNS functions (there’s a post of the drawbacks of detours)

Komodia’s DNS Hijack intercepts all DNS requests before they are leaving the machine and allows the programmer to perform any lookup he desires, this can be done with any language that supports DLLs such as: C/C++, Delphi, .Net, VB

Barak

URL filtering SDK

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URL Filtering SDK are used for programmers or companies that want to develop web content filter, usually for parental control and wants to focus their development on what their clients perceive as advantage: GUI, Support, ease of use. The usage of the SDK frees up development time which is complex and time consuming.

Here at Komodia we developed our URL Filtering SDK for about 3 years. Even you’re going to implement only subset of the functionality, please allow for up to six month of development and QA, and that’s just for the basic functionality.

Barak

Intercepting DNS queries LSP

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It is possible to intercept DNS queries, usually it is done for anonymizers for two reasons:

  1. Even if the session is anonymized the DNS query reveals the destination.
  2. Some countries have their DNS servers censored.

Because of these two reasons when you intercept the DNS you are able to use the domain name via a proxy you tunnel the data to (still assuming we are writing an anonymizer).

What are the ways to do it:

  • Winsock LSP or any other network interception ability like TDI, WFP, NDIS.
  • Use NSP (it’s very rare)
  • Hooking, detours.

Each method has it’s advantage and disadvantage and making the wrong choice can later means starting all over, for example, what works perfect on 32bit may not work at all under 64bit or even worse can’t work on 64bit, or it may not be compatible with all current OS.

We at Komodia’s has an optional module for: “Intercepting DNS queries LSP” which works on Windows 2000 and up to 7 and 2008 including all 64 bit flavors.

Barak

Windows socket hijack outgoing data port 80

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When someone wants to write a program that “hijacks” a windows socket he needs to know which technology to use, there are number of technologies, each with it’s advantages and disadvantages and the programmer needs to make the correct choice, otherwise he will find himself in a world of problems down the road.

In the Winsock LSP page we talk a bit on NDIS, TDI, WFP, and when the new web site design will be up we will also have a more detailed discussion on each technology.

Our flagship product, which allows you to:  “Windows socket hijack outgoing data port 80” which is of course Komodia’s Redirector.

Barak