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http://www.zytrax.com/books/dns/ch4/#slave
http://en.wikipedia.org/wiki/DNS_zone_transfer

unless that was a joke :)

Unfortunately, every untrained technician and their ill-trained supervisor gets these wrong. The flow control lines are not there for laughs: mis-handled, they lead to many unfortunate adventures, at the worst moments. I've had to deal with the errors when someone thought the way you did, failed to connect the flow control to anything, and wound up with jammed serial lines.

The standard is published many places, such as http://www.zytrax.com/tech/layer_1/cables/tech_rs232.htm#db25. Even your "three wire description" has left something important out, that I've seen mis-wired: the third wire is _signal ground_, not "common ground". "Common ground" is when we share something interesting to talk about: it's an unfortunate choice of words for wiring.

It IS a DNS server, just not an authoritative server. DNS servers come in 2 flavors, authoritative servers (which hold the actual info) and recursive servers (which do the looking up for a client).
Most DNS servers do both, so "DNS server" means many different things depending on the context. When your ISP gives you a "DNS server" to use, it's a recursive server, not an authoratative server.
The end user has a "stub resolver", which does not qualify as a server.

For a more indepth discussion of DNS architecture and DNSSEC, you can check out "DNS for Rocket Scientists" here http://www.zytrax.com/books/dns/ or a talk I gave on DNS security here:
http://www.mavensecurity.com/presentations

there are multiple cat5 wiring arrangement standards, which switch wire colors but do not change the basic wiring format:

http://www.zytrax.com/tech/layer_1/cables/tech_lan .htm#color

in my line of work (low-voltage wiring), describing wires by location is typically more precise than describing wires by color.

Just a quick follow-up on my previous post regarding UAs. If you set Opera to identify as IE or Firefox via the per-site preferences (details here), it renders Live Maps almost perfectly. Compare:

• Opera 9.10 identifying as itself
• Opera 9.10 identifying as Firefox viewing the Microsoft campus in bird's eye mode (I specifically closed the scratchpad, as I was unable to remove items from it and really didn't want to post my own address on the interwebs even in picture form)

• Scroll-wheel zoom doesn't work. Scroll-wheel zoom does work in Opera on Google Maps, so this is not a problem native to Opera (such as not exposing events to hook scrolling).
• There are obvious layout problems, but only with the floating controls. IMHO, those need to be cleaned up and re-arranged anyway, so I don't mind them being in the wrong places.
• Some hover controls are missing. Hovering over an item in the scratchpad doesn't produce the popup that allows you to clear the entry, for example.
• Missing close controls on some items. Specifcally, the "Welcome" box is missing its closed "X".

The main reason for that is that nothing really tries to explain what LDAP is.

Which is a shame really, because once you know it's quite easy to understand.

It's a tree-based database which may store objects as well as just text.

Because it's tree based, you don't generally search it like you do with an SQL database (SELECT record FROM table WHERE condition). Instead, you already know at least roughly where what you're interested will be, so you say "starting from this point in the tree, find me this type of record with this value".

TBH, it's easier to explain in person with a whiteboard than it is to write - which is probably why so much of the documentation is so lousy ;) However, if you can stomach it, this seems to be as good an introduction as any - though it's still pretty hairy:

http://www.zytrax.com/books/ldap/ch2/

Depending on the DNS server, turning off recursion completely is not the answer. Granted most internet-facing DNS servers can simply turn recursion off without negatively impacting lookups (generally) but doing so for an internal system (or one that bridges an internal and external) is begging for trouble.

According to Chapter 2.2.6.2 of Pro DNS and BIND (http://www.zytrax.com/books/dns/ch2/index.html#re cursive))

Note: The above sequence is highly artificial since the resolver on Windows and most *nix systems is a stub resolver - which is defined in the standards to be a minimal resolver which cannot follow referrals. If you reconfigure your local PC or Workstation to point to a DNS server that only supports Iterative queries - it will not work. Period.

A better solution would be to use allow-recursion to specify which clients will receive recursive DNS responses.

Depending on the DNS server, turning off recursion completely is not the answer. Granted most internet-facing DNS servers can simply turn recursion off without negatively impacting lookups (generally) but doing so for an internal system (or one that bridges an internal and external) is begging for trouble.

According to Chapter 2.2.6.2 of Pro DNS and BIND (http://www.zytrax.com/books/dns/ch2/index.html#re cursive))

Note: The above sequence is highly artificial since the resolver on Windows and most *nix systems is a stub resolver - which is defined in the standards to be a minimal resolver which cannot follow referrals. If you reconfigure your local PC or Workstation to point to a DNS server that only supports Iterative queries - it will not work. Period.

A better solution would be to use allow-recursion to specify which clients will receive recursive DNS responses.

Another topic of interest is the Fresnel Zone between the two endpoints. Line-of-sight is not sufficient, you have to have the "football-shaped" Fresnel zone free of obstructions. This is most critical near to the antennas.

I think there ar a few routers out there capable of something like that. Check out http://www.zytrax.com/features/qos.htm look slike it might be what you're looking for.

This sounds like pretty basic forwarding. Why do you have to restart your bind when the VPN is up? Are you trying to make it run as a secondary or something? Check out something like (this was the first match on google) http://www.zytrax.com/books/dns/ch7/zone.html you just specify one for the forward and reverse domains of your office to your office nameservers.

Most people that complin about bind dont seem to know how to use it funny as it's got to be the most well documented and standard off all DNS servers.

Into the few-megahertz range, twisted pair wire works remarkably well. This is the stuff we're all familiar with as phone lines and cat-5. The number of twists per unit of length determines how resistant it is to interference, hence cat-5 is much more tightly twisted than cat-3. Each pair in a multipair cable is twisted a slightly different amount, to prevent inductive coupling and crosstalk between pairs.

The signal sent down a twisted pair is bipolar and "balanced", so that the two wires are carrying mirror opposite signals. There's an excellent explanation of this. T-1 signals ride twisted pair for several kilofeet between repeaters. The N-carrier system (low rate analog multiplex) also used twisted pair, but I don't know how far it would go between terminals.

Above a few megahertz, twisted pair gets unacceptably lossy and noisy. Higher speed signals are carried on coaxial cable, which we all know and love for its role in television wiring. The characteristic impedance of coax is determined by the ratio of the center conductor diameter and the distance to the inner surface of the outer conductor. Very early coaxial lines were made by suspending thin rods inside sections of copper pipe, by means of cardboard disc insulators. Soon a method of manufacturing flexible cable was developed, and has remained largely unchanged.

Signals carried on coax are "unbalanced", where the outer conductor is grounded and the inner conductor carries an AC wave. The need for the ground reference means that coax runs between buildings can become part of a ground loop, and cause all sorts of electrical problems. T-3 circuits use coax, but only for very short runs. (A T-3 that leaves a building does so as a DS-3 carried on fiber.) The L-carrier system, which multiplexed several N-carrier signals together, used thick coaxial lines for long-haul runs across the countryside.

As you approach the gigahertz range, coax also becomes too lossy, and hollow waveguide becomes the obvious choice. Waveguide can be rectangular, ovoid, or circular in cross-section, which effects the polarization of the signals carried in it. The inner dimensions influence loss and frequency range. Personally I'm not familiar with the buried waveguide system, but the TD and TH microwave systems used waveguide to connect the antennae with the terminal equipment.

6 pin Firewire pin assignment (& others)

Need to know which ones are the power pins, right? ;)

Anonymous Joe

If companies want to block all user agents from their sites except for MSIE 6.x on Windows XP, there isn't a thing you can do about it.

There's a thing I can do

Of course, then we get into the interesting terrain where misreporting user-agent becomes criminal hacking. I'd love to see that trial!

If you want to use your computer to exercise your right to vote, you must purchase a product from one particular company.

And it's not the browser, either, as you can use Mozilla (Netscape 6x) as long as you're on Microsoft.

I guess it wont make much difference to our servicemen, as they will probably be using Windows anyway, but what about overseas citizens? Do they just change thier user-agent string?

...the ground. Hardware Vendors!

The current problem is that hardware vendors tend to overcharge for their products significantly. Currently, if you looked at breezecom products, the base units and CPE units each cost about $1500-2500 a piece but it costs the hardware vendor about $100-200 per unit to create one unit. Then you got antennae costs, wiring, installation, and each site would then cost you about $3-6000 to setup. If you are charging $75/month to recoup $6000 on a 3 year lease and pay for your other current expenses, you would need about 2-5000 clients to cover your costs. The complete setup above would cost the hardware vendor about $300-500 to make/purchase.

If you want a good wireless solution that is inexpensive (maybe not as fast but works), then check out Zytrax. Their units work with either 115.2kb/sec and a 1.2mb/sec units and should be *nix/*BSD friendly friendly since it runs over ethernet.