[CALUG] More UDP foolishness

[Kelly Price]

On 4/14/06, Jason C. Miller <jason.c.miller at gmail.com> wrote:
> Yeah...but I would hardly call nmap a common utility (at least, not
> NEARLY as common as something like telnet).  I also mentioned that nmap
> is something that I'm using currently and don't want to have to rely
> since I don't want to have to install it wherever I go.
>

Unfortunately, I have rare times at which I use telnet, or even stock
ftp.  Gentoo doesn't install it by default, although most other
distros do.

Of course, I have nmap on my laptop, with a WiFi card and a Ethernet
card.  I don't know if that's allowed in your case (if I remember
correctly).  There are other ways around it of course, including ZIP
disks and USB keydrives.

>                                                   -j
>
>
> Kelly Price wrote:
>
> >On 4/13/06, Jason C. Miller <jason.c.miller at gmail.com> wrote:
> >
> >
> >>Oh...almost forgot.  The UDP port in question doesn't reside on your
> >>local machine.  Therefore, 'netstat' and other tools like that don't
> >>apply.  ;)
> >>
> >>
> >>
> >
> >So we're looking at a remotely connected PC.
> >
> >We need to know where you are connected in relation to that PC, and if
> >your laptop has Linux on it.
> >
> >* If it's on a local network (wire/wireless), nmap.
> >* If it's not, but the PC has an direct IP address and so do you, nmap.
> >* If ether end is firewalled or behind a NAT router, you're screwed!
> >
> >
> >
> >
> >
> >>                                                               -j
> >>
> >>Jason C. Miller wrote:
> >>
> >>
> >>
> >>>Heck....why not!  Here's my random question for the week...  :)
> >>>
> >>>So, anyway, a lot of troubleshooting and investigation is required with
> >>>the stuff that I work on.  For as long as I can remember, I've used
> >>>'telnet' as the simplest way to determine whether or not a TCP port is
> >>>bound to by an application on a machine.  It's simple, quick, easy, and
> >>>comes stock on just about every OS imaginable.  It's a good way to
> >>>verify that the 3-way-handshake works on a given port.
> >>>
> >>>However...
> >>>
> >>>Can't say it's been quite that simple for the UDP side of the house.
> >>>Since UDP is connectionless, the mechanisms for determining if a port is
> >>>bound to is a tad different.  Instead of conveniently getting a
> >>>(RST,ACK) TCP reply, UDP relies on the receipt of ICMP 'Destination
> >>>Unreachable' messages to tell it that the port is not open.  Typically,
> >>>I've relied on applications like nmap.  However, I don't really feel
> >>>like installing it wherever I go.  I've also written simple progs to do
> >>>it, but it's very inconvenient.
> >>>
> >>>So, the question is....can anybody recommend a COMMON program that you
> >>>would find on most operating systems that could be pointed at an
> >>>arbitrary UDP port and would tell you the status of that port?  Seems
> >>>like it'd be simple, but I can't seem to think of any at the moment.
> >>>
> >>>                                                      -j
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> >>>
> >>>
> >>>
> >>--
> >>***************************************************
> >>My blog: http://millersplace.blogspot.com/
> >>***************************************************
> >>
> >>_______________________________________________
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> >>
> >>
> >>
> >
> >
> >--
> >Kelly "STrRedWolf" Price
> >http://strredwolf.furrynet.com
> >
> >
>
>
> --
> ***************************************************
> My blog: http://millersplace.blogspot.com/
> ***************************************************
>
>


--
Kelly "STrRedWolf" Price
http://strredwolf.furrynet.com