Re: [fw-wiz] Radio Ethernet Modem Experiences

From: franco segna (fsegna_at_web.de)
Date: 07/20/04

  • Next message: Matthew Dees: "[fw-wiz] Re: Web server security?"
    To: firewall-wizards@honor.icsalabs.com
    Date: Tue, 20 Jul 2004 09:24:35 +0200
    
    

    For the RF implications and design basics you may take a look at
            http://sandbox.bellanet.org/~onno/the-guide/wifi/
    and for some practical considerations at
            http://www.solwise.co.uk/los.htm
    but for a solid design you will need an RF engineer (endangered species).

     From the security point of view, consider the following:
    1. design only single point-to-point encrypted links (you don't need
    dynamic authentication, and the buildings can safely be defined as static)
    2. use only highly-directive antennas (as allowed from local
    regulations) to greatly reduce the possibility of detection, decoding,
    attacking or jamming (you will need anyway high-gain antennas to reach
    consistently - 99.0% availability - several thousand feet on 802.11b or
    11g). High directivity means very narrow radiation/receiving patterns;
    any motivated attacker would be forced to use a similar antenna, from a
    location comprised in the narrow radiation lobe, and pointed with great
    precision toward one of the link ends.

    Regards
    Franco

    Bruce Platt wrote:
    > This is slightly off-topic.
    >
    > I'm looking for some information on experiences which you may have with
    > Radio Ethernet repeaters. I need to connect several small LANS in separate
    > buildings which are several thousand feet apart and the cost of installing
    > fiber is too great.
    >
    > Data rates will be modest across the entire LAN, so I think I can fit in the
    > bandwidth limitations of some of the 908 Mhz Spread Spectrum devices, or
    > even the 2.4 Ghz 802.11b devices (wep!).
    >
    > Using these as bridges seems like a decent way of accomplishing what I need.
    >
    > Have any of you used these before? I can think of some of the gotchas,
    > like:
    >
    > 1. Oops, another building is in the way, one more unit needed,
    > 2. Signal degradation due to weather,
    > 3. Co-ax length from external antenna to device,
    > 4. Potential security concerns on WEP units, though the data is not greatly
    > sensitive,
    > ...
    >
    > However, I can also see some war-driving type risks which I am not competent
    > to evaluate, though no dhcp servers will run, and all available LAN
    > addresses will be already occupied.
    >
    > Since one doesn't know what one doesn't know, I am happy to learn from what
    > you have to offer.
    >
    > Thanks and regards,
    >
    > Bruce
    > _______________________________________________
    > firewall-wizards mailing list
    > firewall-wizards@honor.icsalabs.com
    > http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
    >

    -- 
    Franco Segna  -  fsegna@web.de
    Key fingerprint = 704C 3070 70A0 680A 760D  025E D849 02AB 2309 87A3
    _______________________________________________
    firewall-wizards mailing list
    firewall-wizards@honor.icsalabs.com
    http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
    

  • Next message: Matthew Dees: "[fw-wiz] Re: Web server security?"

    Relevant Pages

    • Re: building designs
      ... this is being changed....to an ugly new design. ... In new housing estates, the buildings ... The 90% majority of Singaporeans are living in HDB and small coondo ... Architectural designing is NOT in demand in Singapore. ...
      (soc.culture.singapore)
    • Re: Sommer design
      ... In either case a LP design has many solutions for a given frequency range for number of elements, spacing, etc. ... It provides slightly less 'gain' than a 3 element triband Yagi. ... Alf invited me to come to the factory, see the antennas up in the air and see what they have to offer. ... Alf claims that his XP504 LP has the same gain as a 4-element Yagi on the ham bands. ...
      (rec.radio.amateur.antenna)
    • Re: Short antennas - info
      ... antennas a tenth of a wavelength or less. ... For instance it could refer either to element length as well as boom ... Gaussian design where the elements are placed close to planar. ... Gaussians of this style go upto 13 dbi for much less than a 20 foot ...
      (rec.radio.amateur.antenna)
    • Re: LPY antenna designs?
      ... Something with about 4% or 5% bandwidth in the VHF/low ... 'log periodic and yagi' pcb antennas that has apparently been smushed ... just a way to add buzzwords to your antenna design description. ...
      (rec.radio.amateur.antenna)
    • Re: Storm of the..century?
      ... of years and rebuilt to stand up to 140mph+ winds. ... it's not a true statement that all buildings have to be ... Different design criteria for different components ... hurricanes from the previous season. ...
      (rec.boats)