RE: Dynamic server ports -- MIDRANGE-L

Since I asked the question let me address James's and Scott's comments. I
agree that for something like telnet it is silly to have the extra
connection and programming to retrieve the port, but telnet has a IANA
assigned port, it's IS a bloody standard. What about site-specific tools and
applications?

Case in point, I'm developing a PC tool that needs to connect to a listening
socket on the AS/400. How do I know what port to use? Well, I'll just pick
one, what about 12345? OK, everyone hear that? I'M USING 12345, you can't
use it because you might want to use my tool. That is silly, some day, some
where there will be a collision, why not work out a scheme where these
collisions are avoided from the start. You want it on port 12345, fine put
an entry in the service table for com.techsoftinc.pwdtool on port 12345, you
want 54321, fine put that in there it doesn't matter to me.

-Walden

------------
Walden H Leverich III
President
Tech Software
(516)627-3800 x11
WaldenL@TechSoftInc.com
http://www.TechSoftInc.com



-----Original Message-----
From: Scott Klement [mailto:klemscot@klements.com]
Sent: Friday, December 14, 2001 02:42
To: midrange-l@midrange.com
Subject: Re: Dynamic server ports



I agree with James on this.  It's just one more open port in the firewall.
It's just one more program running that has a chance to have a bug in it
that can be exploited.

It doesn't enhance anything.


On Thu, 13 Dec 2001, James Rich wrote:

> On 13 Dec 2001 thomas@inorbit.com wrote:
>
> > Essentially, you connect to port 449 and send in a name from the
> > service table such as "telnet" or "ddm" (case-sensitive and ASCII)
> > and it returns a 32-bit binary port number for that service. To see
> > it in action, just set up a comm trace and watch any PC connect. I
> > have no idea how the same is handled on other platforms; it'd sure
> > make a nice standard.
>
> Well IMNSHO the use of port 449 for this stuff is stupid.  Want to
> connect to the telnet server?  Use port 23.  Want to use other
> services?  Connect to the appropriate port.  But wait, that is what
> 449 is supposed to be: the appropriate port.  Why do we need a
> standard to tell us what is already an existing standard?
>
> Maybe you decide to move telnet off port 23 to help prevent abuse.  I
> can just connect to 449 to find out where it went.  Or do a port scan.
> So what did we gain by using 449?  Nothing - just another firewall
> rule and added complexity.
>
> We already have a standard.  We don't need another one.
>
> p.s.  I'm not upset with anyone (though it may sound that way).  I'm
> just fed up with moronic Client Access that has this special need of
> port 449 when my other 5250 clients work just fine without it.  Kind
> of like the Micorsoft paperclip:  fancy features I don't need or want
> and create headaches.
>

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