Re: Network File serving options

From: Bill Vermillion (bv_at_wjv.comREMOVE)
Date: 10/31/03 

Date: Fri, 31 Oct 2003 03:05:01 GMT

In article <bnrhfg$5o7$1@news.tdl.com>, Justin Robbs
<justin_robbsNO@SPAMhotmail.com> wrote:

>My company has a POS system that we are updating. Currently,
>we have two Openserver machines acting as cash registers and
>one machine that interfaces to our gas pumps and our corporate
>office via dialup. The machines are a mix of 5.0.5 and 5.0.6.

[other stuff deleted - only retaining pertinent part - wjv]

>Security is not a big issue. The only outside access to the
>system is via dial up and the number is not published anywhere.
>Also, the only access the user's have to our system inside the
>store is with a touch screen. The only other input devices
>available are the UPC scanner or credit card/check reader.

Not haveing a published phone number fits the 'security through
obscurity model' - and that has been shown to be one of the worst
security mode that anyone tries.

The old movie 'War Games' shows how easy this was done then, and
it's even easier now.

And now that you have posted this to a global NG all someone has to
do is figure out the city you are calling from.

Callback modems - if you must use modems - are a good route as they
will only call back specific phone numbers.

If you don't go that way you might want to try 'enhanced security
through obscurity'.

You invert the funtions of the modems, so that the server modem
goes on line in originate mode [not answer mode] and you call that
modem in answer mode.

This means that if anyone dials the number they never get a modem
tone, as the modem at the server is waiting for the tone. When you
call the far side you get silence and then your modem issues the
handshake tone.

I've seen this implemented - and at least it will stop the random
dialers who look for an answer tone.

I'll get off my security rant now.

Bill 

-- 
Bill Vermillion - bv @ wjv . com

Relevant Pages

  • Re: Fax is pending, sent before
    ... You don't indicate if you could hear the relay click when the modem went off hook, dial tones or touch tone sounds from the computer speaker or a mini speaker on the modem board. ... When modem is "on hook" the two jacks are connected to each other, allowing you to hear a dial tone or talk on a phone attached to the modem. ... This allows multiple area codes in your toll free calling area and frees up a few more number combinations for exchanges to accommodate additional customers in each area code. ...
    (microsoft.public.windowsxp.print_fax)
  • Re: History AT&T early modem developments? [telecom]
    ... The TWX version of the ... ringing, busy tone, reorder, connected, etc. ... ever developed a modem that could reliably recognize all these conditions. ... Concerning time sharing, a lot of the early time sharing systems were ...
    (comp.dcom.telecom)
  • Re: Network File serving options
    ... > Not haveing a published phone number fits the 'security through ... > security mode that anyone tries. ... > modem in answer mode. ... > tone, as the modem at the server is waiting for the tone. ...
    (comp.unix.sco.misc)
  • Re: No Dialtone when send/receive fax
    ... I'd followed your suggestion and swapped the line/phone cables connection. ... I purchased a USB modem for diagnostics of just ... em can't detect tone then, ... Apparently a relay disconnects the telephone jack when the modem ...
    (microsoft.public.windowsxp.print_fax)
  • Re: No Dialtone when send/receive fax
    ... view log>"review the modem response log for error". ... That means that my tone was detectable, ... cycle that modem's initialization, it would not longer ... terminates your dial up ISP connection up and establishes a new data ...
    (microsoft.public.windowsxp.print_fax)
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