This is driving me crazy - why is my router still STEALTHED? - Firewalls

This is a discussion on This is driving me crazy - why is my router still STEALTHED? - Firewalls ; I am trying to test some settings on my router that allow certain ports (e.g. 139) to be open for inbound traffic - via port forwarding. For that, I use a port scan service like ShieldsUp on www.grc.com or auditmypc.com. ...

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Thread: This is driving me crazy - why is my router still STEALTHED?

  1. This is driving me crazy - why is my router still STEALTHED?

    I am trying to test some settings on my router that allow certain
    ports (e.g. 139) to be open for inbound traffic - via port forwarding.

    For that, I use a port scan service like ShieldsUp on www.grc.com or
    auditmypc.com.

    However, no matter what I do (I even did port forwarding on ALL ports
    to my test PC (running XP with its firewall turned off), the test
    results always show ALL ports as stealthed.

    Internally (in my LAN) I used a Linux port scanner to verify that my
    test PC indeed has at least ports 135, 139 and 445 open. They are
    definitely open on the test PC.

    I also temporarily configured my router to set the test PC as a DMZ
    (on my NETGEAR router it is call "Default DMZ Server") - and indeed
    the www.grc.com test showed those ports as open.

    However, I don't understand what is the difference between this
    "officially labeled" DMZ setting to port forwarding of ALL the ports.
    Could someone please help me understand this?

    For example, is it possible that a DMZ server is being skipped the NAT
    done by the router? (despite it retaining the internal LAN address?)

    Thanks,
    Alex

  2. Re: This is driving me crazy - why is my router still STEALTHED?

    On Nov 27, 10:55 am, xp_new...@yahoo.com wrote:
    > I am trying to test some settings on my router that allow certain
    > ports (e.g. 139) to be open for inbound traffic - via port forwarding.
    >
    > For that, I use a port scan service like ShieldsUp onwww.grc.comor
    > auditmypc.com.
    >
    > However, no matter what I do (I even did port forwarding on ALL ports
    > to my test PC (running XP with its firewall turned off), the test
    > results always show ALL ports as stealthed.
    >
    > Internally (in my LAN) I used a Linux port scanner to verify that my
    > test PC indeed has at least ports 135, 139 and 445 open. They are
    > definitely open on the test PC.
    >
    > I also temporarily configured my router to set the test PC as a DMZ
    > (on my NETGEAR router it is call "Default DMZ Server") - and indeed
    > thewww.grc.comtest showed those ports as open.
    >
    > However, I don't understand what is the difference between this
    > "officially labeled" DMZ setting to port forwarding of ALL the ports.
    > Could someone please help me understand this?
    >
    > For example, is it possible that a DMZ server is being skipped the NAT
    > done by the router? (despite it retaining the internal LAN address?)
    >


    OK - things start making more sense right now: instead of forwarding
    ALL ports (0..65535) to my test PC, I enabled only 135..445. That
    effectively made my test PC apear as unstealthed (in ports 139 and
    445) to the www.grc.com test.

    This confirms my understanding that DMZ is nothing more than port
    forwarding to all usable ports (except for port 0 or some other
    strange ones like 8 (ICMP)).

    Or did I get it completely wrong?

    Thanks,
    Alex


  3. Re: This is driving me crazy - why is my router still STEALTHED?

    xp_newbie@yahoo.com wrote:
    > On Nov 27, 10:55 am, xp_new...@yahoo.com wrote:
    >> I am trying to test some settings on my router that allow certain
    >> ports (e.g. 139) to be open for inbound traffic - via port forwarding.
    >>
    >> For that, I use a port scan service like ShieldsUp onwww.grc.comor
    >> auditmypc.com.
    >>
    >> However, no matter what I do (I even did port forwarding on ALL ports
    >> to my test PC (running XP with its firewall turned off), the test
    >> results always show ALL ports as stealthed.
    >>
    >> Internally (in my LAN) I used a Linux port scanner to verify that my
    >> test PC indeed has at least ports 135, 139 and 445 open. They are
    >> definitely open on the test PC.
    >>
    >> I also temporarily configured my router to set the test PC as a DMZ
    >> (on my NETGEAR router it is call "Default DMZ Server") - and indeed
    >> thewww.grc.comtest showed those ports as open.
    >>
    >> However, I don't understand what is the difference between this
    >> "officially labeled" DMZ setting to port forwarding of ALL the ports.
    >> Could someone please help me understand this?
    >>
    >> For example, is it possible that a DMZ server is being skipped the NAT
    >> done by the router? (despite it retaining the internal LAN address?)
    >>

    >
    > OK - things start making more sense right now: instead of forwarding
    > ALL ports (0..65535) to my test PC, I enabled only 135..445. That
    > effectively made my test PC apear as unstealthed (in ports 139 and
    > 445) to the www.grc.com test.
    >
    > This confirms my understanding that DMZ is nothing more than port
    > forwarding to all usable ports (except for port 0 or some other
    > strange ones like 8 (ICMP)).
    >
    > Or did I get it completely wrong?
    >
    > Thanks,
    > Alex
    >


    lol,

    You got it partially correct, with the exception that "Port Forwarding"
    and DMZ can be used together, with Port Forwarding taking precedence on
    which ports are forwarded, and the rest going to the DMZ.

  4. Re: This is driving me crazy - why is my router still STEALTHED?

    xp_newbie@yahoo.com wrote:

    > This confirms my understanding that DMZ is nothing more than port
    > forwarding to all usable ports (except for port 0 or some other
    > strange ones like 8 (ICMP)).


    Nitpick: ICMP isn't a "port", it's a protocol. Ports are only used in
    TCP and UDP.

    Juergen Nieveler
    --
    We cannot live by power, and a culture that seeks to live by it becomes
    brutal and sterile. But we can die without it.
    Max Lerner

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