How to manage (Proxy) Re-Routing Packages?

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This topic contains 6 replies, has 2 voices, and was last updated by  kf 10 years, 3 months ago.

Viewing 7 posts - 1 through 7 (of 7 total)
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  • #5123

    kf
    Participant

    Hi,

    WinPk-Filter:

    it is possible to capture packes from a specific port an re-route it to an other ip?

    Can i change the dest. & src IP-Address in the IP-Header?

    Which stuff has to be modified?
    Bye

    #6404

    kf
    Participant

    Hm… i tried to remote all destination informations like:


    ::ZeroMemory( &pIpHeader->ip_dst, sizeof(in_addr));

    but the messages archive the goals?

    Any ideas? 🙄

    #6405

    Vadim Smirnov
    Moderator

    it is possible to capture packes from a specific port an re-route it to an other ip?

    Can i change the dest. & src IP-Address in the IP-Header?

    Which stuff has to be modified?

    Yes this is possible and it is as simple as changing IP/TCP/UDP header and recalculating the checksums. Also if this is sort of redirect the reversed operation should be performed in reversed packets.

    Internet Gateway sample http://www.ntkernel.com/w&p.php?id=31demonstrates the usage of WinpkFilter for implementing NAT solution.

    #6406

    kf
    Participant

    Hm, thx. That is an empty url?

    EDIT: Sry the url is perfect 🙂

    #6407

    kf
    Participant

    The Source-code download requires an username & password ? 🙄

    #6408

    kf
    Participant

    I’ve found the source-code fore a new checksum.

    Can i change the ip-address(es) and recompute the checksum is that everything i need?


    ::ZeroMemory( &pIpHeader->ip_dst, sizeof(in_addr));
    ::ZeroMemory( &pIpHeader->ip_src, sizeof(in_addr));

    ::RecalculateTCPChecksum( &PacketBuffer );

    hmm whats wrong?

    #6409

    kf
    Participant

    Okay it works fine! Thx. That link was very helpful:
    http://www.ntndis.com/forum/viewtopic.php?p=917&sid=d5925c2d83c622468d49c84caca81b75
    http://www.ntkernel.com/forum/viewtopic.php?t=550&highlight=check+cheque+sum

    So my last question (problem):

    If i use the RecalculateIPChecksum() without changing the ip-address, the packages are droped in the pipeline?


    RecalculateIPChecksum( &PacketBuffer );

    Next, How can i enter an ip-adress? (to: pIpHeader->ip_dst)
    e.g. 192.168.1.9 ?

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