RedHat Ethernet adapter problem

[Parag Mokal]

hello everybody,
I've Redhat linux 7.0 installed on my machine. I've successfully installed the lan card on it. I configured the ip-address, gateway of last resort for it, but I'm unable to connect to the nework. when I ping the other machines on the network, I'm unable to reach them. I can successfully connect them on win'98.
Does the redhat require anything extra to be configured or is there any problem with the redhat version itself?

[Michael Ernest]

Are you using the same subnet mask as other machines on the network?
[ November 18, 2002: Message edited by: Michael Ernest ]

[Parag Mokal]

Hi,
The subnet-mask of my machine is different from that of others. But does it matter? If yes, how does it matter?
Do I have to make some more configurations?

[Michael Ernest]

The subnet mask is a number that helps split your IP address into two parts: a network number and a station number.
In conventional IPv4 usage, the number itself specified a class for this split, based on the first (high-order) three bits of a 32-bit IP number. If the first bit is zero, you have a class A address, meaning the high 8 bits of the IP are the network number, e.g.:

10.15.0.1 -- or 00001010000011110000000000000001 in 32-bit representation.

That's a class A address. Class B addresses reserve the high 16 bits to describe the network number, the lower 16 for a station. Finally, class C addresses use the high 24 bits for the network, the last 8 for the station.
In modern small networks, subsets other than these canoncial classes get used so that you can get more than one "subnetwork" out of a class address.
So if your system doesn't agree with the others on your subnet which part of the number is network, and which part of the number defines a station, you aren't going to be able to hear them because you're not going to recognize them.
I don't know how Linux does this. In Solaris, we use ifconfig(1M) to change an adapter dynamically, and we define subnets in a file called /etc/netmasks. I'd look for those two things first, and failing that, ask somebody who knows what the Linux equivalents for this program and file are called.

[Adam Hardy]

in linux there's an easy dialog box in the network configuration settings, when you're using KDE
If you want to know which file it keeps it in, I'd have to look it up in Aeleen Frisch's Sys Admin book.

[Tim Holloway]

The RedHat network config program writes its config info into /etc/sysconfig and /etc/sysconfig/network-scripts.
The subnet mask is a number that allows the 32-bit IP (V4) address to be broken up into 2 parts - the network identifier and the host identifier, so if the subnet mask on your machine isn't the same as the subnet masks for the other machines on your network segment, things won't decode properly.