RE: discovering a service behind a nated network

From: CHRIS GRABENSTEIN (CGRABENSTEIN_at_lfcc.edu)
Date: 09/07/04

  • Next message: Mike: "RE: Web ports list" 
    Date: Tue, 7 Sep 2004 16:10:46 -0400
To: "linux user" <linuxteam@gmail.com>, <security-basics@securityfocus.com>

    If the company has not restricted IP Options and ICMP, I believe you could
    use loose source routing to do a tracert and take note of where the failures
    start (e.g. at the NAT server or beyond). Just specify the NAT server in the
    route. I would hope the firewall guys had restricted IP Options though.
    Take a look at
    http://support.microsoft.com/default.aspx?scid=kb;en-us;q169206

    -----Original Message-----
    From: linux user [mailto:linuxteam@gmail.com]
    Sent: Saturday, September 04, 2004 8:55 AM
    To: security-basics@securityfocus.com
    Subject: discovering a service behind a nated network

    Hiya All,
     
    I would like to discover if a service that is behind a NATed network is still
    working, for example if a web server is in a private network, Nated behind a
    gateway, how could i from an external network check if the server is down/ or
    there are network problems between the server and the gateway? is there a way
    to use a tool such as traceroute for NATed/Firewalled network from an
    external link?

    The reason i am asking this is because i have been asked that question on a
    job interview, and i did not know what the correct answer was, it was
    related to a web cluster farm then.

    another reason is howto troubleshoot a service that has been port forwarded
    from the gateway, the port forwarding works for other services, but this
    specific service is not reachable, and you can not tell whether the NATed box
    was down, or the route was down, or what, you could debate that you can use
    ssh to the gateway server, but then that is run by a different dept. and you
    have no access to that.

    sorry if my English langauge is a bit rusty

    TIA

    Anst

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  • Next message: Mike: "RE: Web ports list"

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