Category Archives: Hardware

Dell Inspiron 5558 Review

I’ve never done a hardware review before (with the exception of the odd Amazon review), so bear with me.

For those who’ve been following my rarely updated blog, I’ve been plagued with laptop issues for a while (here, here, here and here – oddly enough all LCD related) so I figured it was about time I found some sort of reliable work horse that I can just *get stuff done* rather than having to faff around with hardware every handful of months (the last post about LVDS cables covers a significant period of time, and recently started playing up again). So it was about time for a change.

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A lesson on LVDS, impedance and cheap cables from China

A handful of months ago, my laptop (Lenovo Ideapad Y500 for those wondering) started suffering with screen issues. Specifically the ones that result from the tiny wires in the LCD cables shearing in the hinges. Taking it upon myself to go to eBay to find a replacement, I found a single seller selling the part for the grand total of $15, all the way from some hole in China. Estimated delivery 3-4 weeks. *sigh*.

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Compaq CQ60 Display Issues – The Unexpected Part 3

I recently had an unexpected part 3 to this tale the other day, when the display went. Again. But this time, different symptoms. This time, the backlight went. Oh sh*t, replacing LCD panels isn’t exactly cheap, and since the backlight diffusers and CCFL’s are fused to the back of the LCD panel itself, there was no way of replacing the individual unit.

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Compaq CQ60 Display Woes – Part 2

So in my previous post relating to this, I’d sent the machine back twice to HP to be repaired. The first visit gained a new motherboard and CPU. The second visit gained a new LCD assembly. But still the fault persisted. It sort of worked alright-ish for around a week or so, but then gave up the ghost completely. Sometimes the backlight would come on but no picture. Having had enough of it at this point, I phoned HP technical support a third time, claiming to them it would be my last call before phoning their Customer Complaints department.

So last Wednesday (July 14th 2010), it got picked up again, and was delivered back to me yesterday (Monday July 19th 2010). What did the service report say this time? I hear you ask.. “LCD cable replaced”… Are you serious? All this for a f*cking piece of wire? However annoyed I was at what their resolution was this time, so far it’s behaved exactly as it should. Resolved? Dare I say it this time? Yes…

So, third time lucky. In the meantime, I’ve found that the CQ60 isn’t on sale ANYWHERE anymore. It’s been deprecated and replaced with it’s mate, the CQ61. Casandra has one. There’s some key changes to the chassis and port placement on the unit. The power connector is on the opposite side to the CQ60. I assume that the Graphics, CPU and Power circuitry all the same corner of the board causes somewhat of a problem. I dunno. Either way..

Managing hack/DoS attempts automatically

I was recently recommended some software to prevent (or at least act on) automated hack/DoS attacks on services. The usual suspects triggered this, dictionary attempts on common usernames on servers, “admin”, “administrator”, “root”, etc. Up until now, I’ve been monitoring for unusual network activity. When the traffic reached a certain peak for a specific length of time which was out of the ordinary, I knew something was going on. The hard job then was trying to find out which service was being targeted. I started on the usual suspects, proftpd, ssh, httpd. What I wasn’t expecting at this particular point was someone trying to hack open apache.

Anyway, I digress. The software is called fail2ban. Basically, it’s a python daemon which you configure to sit and monitor the log files from all your exposed services. It uses various timestamp algorithms along with checking using regex for failed auth attempts (configurable). In the regex, it also uses extraction parentheses to extract the host/IP address, then automatically turns to iptables and bans the host within a certain number of failed auth attempts. It defaults to 3 failed attempts getting you a 10 minute ban, but again this is configurable. I’ve set mine to 3 failed attempts with a 30 minute ban, and it seems to be quite happy with that. Since then I’ve actually noticed server load go down a touch, which tells me how many times my servers were being targetted without me even knowing it!

And since it’s configurable for practically every service that logs to a file, it’ll also work for custom applications that do the same thing, no matter what they are. I’ll have to bear this in mind when I write stuff in the future that could be prone to hack attempts.

Check it out: fail2ban