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How bout a FAQ on networking protocol?  That would be cool

How bout a FAQ on networking protocol?  That would be cool

Well, it's not what I'd call a FAQ, but it's a great reference for virtually all network protocols:

    http://www.networksorcery.com/enp/default0501.htm

There seem to be a lot of misconceptions out there about ethernet speed and duplex, especially with the auto negotiation feature (which we networking professionals universally hate, by the way). The devices at the ends of the ethernet cable must agree on both the speed and duplex. If they don't, a few packets may miraculously make it through, but only a few. In the old days, you just set each device to the same settings and it just worked. Then auto negotiation came around and people thought everything would be easier, but there was no standard for how it was supposed to work, so it frequently didn't. As it became more popular many devices dropped the option to manually set the speed and duplex, so then it became an exercise in trial and error to see what magic combination of settings worked. Then things sort of standardized on Intel's method of auto negotiation, so it started working a little better, but still not always. The problem is that auto negotiation only works when both devices do it. If one device attempts to auto negotiate and the other device doesn't do it, the first device is supposed to fall back to 10/half, and it seems that most devices do that these days (but not all). So, the upshot is that if you have a device that you can't manually set to what you want and the auto feature isn't working, your only real alternative is to force the one device you can set to 10/half. You could try setting it to something else, but if it works it's because you're lucky, not because you're smart. To make matters worse, auto negotiation will work fine for months and months and then might one day just decide to break, after which time it'll probably never work again between those two devices (we have an old Dell PC that did that with our SMC router - it's now manually set to 10/half and is just fine). Also, some devices just never work at all with each other, in which case your only option is to replace one of them or put some other device in between them so they'll negotiate with that device instead of each other. We run into that with some regularity at work with customers who have small Cisco routers and cheap little hubs and/or switches.

Given this, how hard should you try to get your device(s) to run at 100/Full?  Well, if you just have a single machine and are connecting to a gateway/router/firewall through a cable/DSL connection to the Internet, then you probably won't notice much or any difference unless you have an exceptionally fast connection to your ISP (like 6 to 8 Mbits/sec).  Even then, you probably won't notice a huge difference because the latency to the Internet becomes a significant factor.  However, if you have multiple machines on your local network and you share files or otherwise move significant amounts of data between them, then having them all run at 100/Full can make a significant difference.  If you do happen to have a bad combination of devices that just won't agree to talk at 100/Full, then getting one of those cheap 4 or 5 port 10/100 switches and putting it in between the two incompatible devices will frequently work (they're usually around $25 to $35, and, in spite of the occasional compatibility issue, they tend to work pretty well - I've had very good luck with Netgear and Linksys switches).  Swapping cables usually doesn't help, though swapping ethernet cards can, since different manufacturers seem to implement autonegotiation differently.

HTH

Dana
CCIE #1937

Excellent.... I just finished up some network info charts (PDF's) and would like some feedback before I submit them to search engines.

Here they are:
http://homepage.mac.com/iTiburon/Networ … etwork.pdf
http://homepage.mac.com/iTiburon/Networ … etwork.pdf
http://homepage.mac.com/iTiburon/Networ … etwork.pdf

hawking updated their product, now using a realtek based chip, works better, the one i linkled to started to flake on me due to heat issues i believe, the new one is better:
http://www.hawkingtech.com/prodSpec.php?ProdID=177
usually less than $50.

apple airport 3.1 and newer support any braodcom based 802.11g NIC without any mods, manu. are:
airlink+, linksys, and buffalo all use this chip, i prefer the buffalo because their cardbus adapter has an MC ext. antenna connector, their PCI uses the same connector and comes with an omni antenna.

You should add crossover and straighthrough cables to the FAQ - including when each is used. I sometimes have to look up when I need to use which.

More and more devices are becoming auto-sensing, meaning you can use either, but a lot still is not.

Airport Express requires a 1/8" mini male connector to (probably) 2 RCA male connectors, which then plug into an available input on your stereo system.

Name your Airport Express

Choose that name in iTunes (lower right hand corner)

I think you need a wireless connection to be able to even set it up.  I used the laptop then connect from a wired iMac.

The man is trying to hack my machine. How can I get him out?

I have a mac and I have my firewall setup and I am watching my log and I am constantly getting everyone it seems attempts to hack my machine. I am getting stealth mode attempts, TCP attempts and UDP attempt.

I who is some of the IP addresses that are attempting to get in and they are coming from all over the globe. Cable Companies. A Company the tracks copyrights. and something called RIPE.

What is the deal? How can I shut them out or is there someone that I can report this to?

Please help or it's take out the hard drive and reload the system.