discovering a service behind a nated network

From: Hayden Searle (hayden.searle_at_safecom.co.nz)
Date: 09/10/04

  • Next message: CHRIS GRABENSTEIN: "RE: discovering a service behind a nated network" 
    Date: Fri, 10 Sep 2004 23:23:54 +1200
To: <security-basics@securityfocus.com>

    I agree with Jason that Nagios is a good way to monitor the web servers,
    or you could talk them into some BigIP F5's which load balance, monitor
    and report on services.

     As for the port forwarding, well it depends on what the gateway device
    is. If it's a firewall then I would get the dept that look after it to
    SSH onto the firewall and try to access the server from there, if that
    works then it could be the translation on the gateway device not working
    properly. Most devices should be able to tell you if the translation is
    working through the logs, but in the end it really comes down to what
    the device is and what logging is setup for the connections. They need
    to give some more info before you could answer that. The simple way out
    would be "Call the other department and have them check the gateway
    device"

    Regards

    Hayden Searle
    Network Security Specialist

    -----Original Message-----
    From: linux user [mailto:linuxteam@gmail.com]
    Sent: Sunday, 5 September 2004 12:55 a.m.
    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: CHRIS GRABENSTEIN: "RE: discovering a service behind a nated network"

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