Linux And Flaky ATL1C Support

Here’s something I thought I’d never see — the day that wired networking in Linux could ever be considered anything less than “it just works.”

I recently purchased a laptop (Toshiba Satellite C655D-S5518 to be precise) and had trouble out of the gate after installing Arch Linux.  The computer would seem to hang whenever the network was involved.  (E.g., running netcfg, networkmanager, or the ip command.)  I assumed that it was wireless support that was causing the headaches, so I ran hwinfo --netcard | grep "Modules\|File" to find the kernel modules related to my networking devices.

Device Modules: "atl1c"
Device File: eth0
Driver Modules: "rtl8192ce"
Device File: wlan0

I blacklisted rtl8192ce but that didn’t solve my problem. 

WARNING: Your NIC (or Driver) Might Lie About MTU

This is one for the ages. I had two problems creep in at once. The first was shoddy NFS performance. I Googled my way across the internet for troubleshooting and performance tips. However, nothing seemed to improve the situation. While that was going on, I noticed the second problem — one of the hard drives was failing its own SMART test.

I was already up late, and the last thing I wanted to be bothered with was finding out which drive it was, going the manufacturer’s site to download their drive diagnostic boot CD, getting the warranty return code, and starting the RMA process. But I hung in there and pulled through.

After some sleep, I tried tinkering with a few more networking settings. I was still coming up with nothing, so I ordered a Cat6 cross-over cable so I could at least rule either way on the cabling and network switch.

HOWTO: Optimize Gigabit Networking in Linux

Even if you have a gigabit networking adapter and a gigabit switch capable of jumbo frames, Linux still uses the default MTU size of 1500. To get something better, you need to configure things by hand.

The reason for this is that the IETF has never standardized anything above 1500. You might very well have gigabit ethernet equipment that either does not have jumbo frame support, or may be very disappointed to find out that “jumbo frame” can be used to describe any packet size between 1500 and 9000.

To make matters worse, not every gigabit ethernet switch handles mixed networking the same. You would think a gigabit switch would guarantee a 1gb connection between two computers with 1gb networking adapters, but under various circumstances, this isn’t always the case. Optimally, it would be best to separate your 100mb and 1gb devices onto two different switches, but this isn’t guaranteed to work.

Now that we have all the caveats out of the way, read on if you want to start optimizing.

Review: Netgear WGT624v3

I’ve used this router for years, and it’s performed dutifully until recently. With recent firmware updates however, two notable feature have stopped working correctly: listing devices that have opened ports using Universal Plug N Play (UPnP) and having the router detect and fetch firmware updates itself.

HOWTO: Hook Up A New Router

You’re probably asking yourself, “This guy complains about things like software RAID, Linux printer drivers, and PHP coding goofs. Why cover a simple topic like hooking up a router?” The answer is simple: I’m taking the router installation BACK. I’m taking it out of the hands of companies that treat their users like morons by including CDs that “do everything for them,” when really it just leaves them more in the dark about how their router works.

In other words, two comments asking for help on their router centering around the installation CD was enough to drive me up a wall. 🙂

Here’s the way to set up ANY router:

Avoiding UPnP with XBox Live?

In my little howto, HOWTO: Set Up A Segregated Network, I ended the article on a bit of a downer. UPnP is a one-stop thing. With a setup where your data is being sent through two routers, Universal Plug ‘n’ Play (UPnP) data only gets sent to the first one. Well, guess what? XBox Live communicates over port 3074 via TCP and UPD, and port 88 via UDP.

Guess what you have to do to get XBox Live working?

1. Give your XBox 360 a static IP address on the secure WAP/wired network.
2. Give your secure WAP router a static IP address on the insecure WEP network.
3. Set up the secure network’s router to forward the aforementioned ports to the IP address of your XBox 360.
4. Set up the insecure network’s router to forward the aforementioned ports to the IP address of your secure router.

Now, this doesn’t guarantee everything under the sun. I’m sure games are able to open more ports. But heck, the only problem I’ve had thus far without this solution was the occasional inability to hear certain people’s voice.

HOWNOTTO: Set Up A Segregated Home Network.

If you want to know why I call myself The Brainwrecked Tech, here’s a good example of why. While browsing the net for information in creating my last article, I came across the book Wireless Network Hacks & Mods For Dummies. Someone got paid to come up with this! For the For Dummies series, no less! And they got it wrong! And here I sit, getting paid zilch to tell you how to do it right.

HOWTO: Set Up A Segregated Home Network.

So, you have a wireless network. You know a little about wireless security. You know WPA is stronger than WEP, so you set up your wireless network for WPA. But, you still have some Wi-Fi devices that can only use WEP. If you keep WPA, you’re SOL. If you downgrade to WEP, you’re going to be SOL in under 60 seconds if some evil-doer comes within range. You want two networks that can’t see each other, but you’re not sure how to pull that off.

REVIEW: Belkin F5D7230-4 Wireless Router

What should have been so simple turned into one of the most frustrating 60 minutes of my life. I bought this router because I wanted to set up a segregated network for WEP devices to hop on to my network and use the internet. You couldn’t pay me $40 to use this device, let alone have me pay $40.