cat5, tcp/ip, routers, hubs and some advice

[jimmy5k]

i've been through a few moderately dicey networks. always with incompatible drivers, NICs conflicting, Old hardware interference, dodgy cables.. and incorrect setups. If nobody objects, i'd like to have a bit of a spiel.

GENERAL ADVICE (some may disagree and pull this to pieces. this is my experience. feel free to add "constructive" criticism)
1)Routers are not hubs
- but can be jury rigged and used for that purpose.
some problems to take into consideration is that routers have a wan port. sometimes this makes other machines think THIS is how to access a shared internet connection. that is bad.

adsl modems/cable connections go in wan ports. I've tried for weeks to attempt to make a pc plug into the wan port. doesnt work.

2) two pcs can not (generally) connect to each other. they require a crossover cable.

3) not all routers/hubs detect the difference between crossover and straight.

4) personal advice, do not hook up multiple network interface cards unless you know what you are doing. use the KISS rule (Keep it Simple, S......)

[jimmy5k]

IP ADDRESSING/SUBNET MASKING
personally, to be sure that the network connection works, you can usually tell by the lights on the back of the card. one should be Conn or something, indicating theres a connection. Tx flashes when there is transferring going on.

some NIC's light up a different connection color if not connected/conflicting. this is handy.

so, to start, make sure your nic works. plug it into a hub (or another computer if using cat5 crossover).

if the hub lights up, and your network lights up, all is good. move on to IP addressing.
IP addresses are complicated things. generally there is a standard, 192.168.0.x where x is the individual computer's number. you can assign anything but this is typically the way it goes. subnet masks are the way the ip range is locked down (restricted to).
EG
192.168.0.4 -valid ip number
255.255.255.0-Typical subnet mask, allows access to only ip addresses from 192.168.0.1 to 192.168.0.254

(wireless nuts usually modify it so their 802.11 gear is on 192.168.1.x range but thats irrelevant atm)

so, now you have a machine with an ip address, and a subnet mask. if another computer logs in with the same ip address, there will be a mess. so, make sure every computer uses a different ip address.

There is something called DHCP, which assigns IP addresses automatically. for the purposes of troubleshooting basic network connectivity to begin with... lets stick to static ip addressing.

now, second computer. you do all the basic checks. make sure the lights are green, and hook into the network. you have an ip address along the same range, but not the same address. we are going to learn to ping. linux users should know ping, and so should anyone in networking. a ping is a little message that gets sent to an address, and a reply comes back, providing the address exists to reply.

so, lets say comp1 is 192.168.0.2 and comp2 is 192.168.0.3
from comp1, if you open your command prompt/terminal window and type ping 192.168.0.3, providing everything is connected, you get a response.

from comp2 if you open your command promt/termina window and type ping 192.168.0.2, providing everything works, you get a response.

this is Networking for Novices 101

[jimmy5k]

its best to understand the kind of outlay you want.
"I have an internet connection i want to share"
Router or PC/Hub

"I just want to share stuff and play games with other computers in the house"
Hub. unless its just 2 PCs, then its just crossover.

heres a little tidbit advice. cat5 has a standard range of 50 meters avoid going over that if you can. i've seen it go on a 100m stretch but was very lossy.

Internet Sharing
- I hate this with a passion. if you have a dialup connection, and you want to use a router... be sure to get one with a serial connection. you can hook your modem straight up to it.
- If you have an adsl modem (ethernet) then this puppy can plug into almost any router. just configure both properly. i'll go into details later.
- other (people talk of "cable" and i dont know the correct terminology as i'm not an american. i assume its pppoe or something similar)
-PC Server
Ultimately the more controlled choice, the PC connects to the net, and you share its connection over an ethernet card (for everyone on the hub to access). fairly straight forward under windows. when this happens, your machine generally has the forced ip address of 192.168.0.1

[jimmy5k]

the number of times i've seen this happen, and i've tried myself. its annoying to say the least.

the thing is routers always want to share THEIR internet connection.
and the problem with that is, you want to share a DIFFERENT connection.

unless you buy a wireless router with a serial port... but nobody ever thinks that far ahead.

the trick is to share it via a lan port. get your machine with the modem and share its internet connection over the lan. make sure the router's ip address is NOT 192.168.0.1 otherwise you wont be allowed to connect the server to the lan.

now another important thing, turn off the router's DHCP. it does affect things. now providing nothing is plugged into the router's wan port, and other pcs are wirelessly and flawlessly connected using nice unique ip numbers along the same range as the server[192.168.0.1] then they should for all intents and purposes be able to connect to the net. be warned. the connection will be insanely slow. and this is a solution only for combo wired/wireless routers. i'm still exploring problems with this though. i will keep people posted.