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protocol 50 ?

Discussion in 'Networking (Hardware & Software)' started by Hugh Jarss, 2005/03/28.

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  1. 2005/03/28
    Hugh Jarss

    Hugh Jarss Inactive Thread Starter

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    Hi

    (Kerio) firewall just prompted me about an incoming connection "unknown event" indicating it was using "Protocol No: 50 "; (application at my end TCP/IP kernel driver) - which I denied...

    curious about what this is - and would appreciate any thoughts or references I could look up

    TIA

    best wishes, HJ
     
    Hugh Jarss,
    #1
  2. 2005/03/28
    Dennis L Lifetime Subscription

    Dennis L Inactive Alumni

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    Sorry Hugh
    I'm no network specialist, but my first Google hits seem to be related to SuSE (Linux) and / or VPN. Are you using these in your configuration?
     
    Dennis L,
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  4. 2005/03/28
    TonyT

    TonyT SuperGeek Staff

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    It's just someone scanning a range of computer ips looking for one that has port 50-51 open. These ports are used by IPSEC for encrypted tcp/ip communications, such as Virtual Private Networks and others. No worries, the prober is likely after corporate networks, by scanning residential ips in the hopes of discovering an unsecured or weak IPSEC implementation.

    IPSEC:
    http://www.webopedia.com/TERM/I/IPsec.html
     
    TonyT,
    #3
  5. 2005/03/28
    BenMcDonald[MS]

    BenMcDonald[MS] Inactive

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    To ammend TonyT's post - page 8 of the RFC http://rfc.net/rfc1700.html

     
    BenMcDonald[MS],
    #4
  6. 2005/03/29
    Hugh Jarss

    Hugh Jarss Inactive Thread Starter

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    gosh - a plethora of peculiar protocols!

    this page was useful, in conjunction with the list from the link in Ben's post; at last, some understanding of how the firewall susses which protocol is being slung at it (ten bytes into the IP header). How the firewall discriminates between the various protocols is something I'd always wanted to find out.

    I've installed winpcap and ethereal and had a go - yup, it works, can see the IP headers and the protocol byte - quite fascinating

    thanks to all who replied for starting off a highly rewarding trawl

    best wishes, HJ
     
    Hugh Jarss,
    #5
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