While I do have a few methods for blocking these guys in place, just this morning I noticed that one particular crawler, identifying itself as “INA dlweb; http://ina.fr/” and coming from 195.221.138.170, was really killing my machine. The only solution was to reconfigure my firewall to drop all packets coming from this IP address.

If you’ve got a server with the very popular LAMP setup (Linux/Apache/Mysql/Php), you can likely do the same.

Here’s how: As root, enter:
iptables -A INPUT -s a.b.c.d -j DROP

, where a.b.c.d is the IP address of the offending web bot. In my case, I entered “iptables -A INPUT -s 195.221.138.170 -j DROP”.

Worked like a charm – my server load dropped drastically:

Before the Change:
10:37:01 up 241 days, 18:20, 3 users, load average: 1.26, 0.70, 0.47
10:38:01 up 241 days, 18:21, 3 users, load average: 1.13, 0.73, 0.49


After the Change:

11:21:01 up 241 days, 19:04, 3 users, load average: 0.40, 0.55, 0.64
11:22:01 up 241 days, 19:05, 3 users, load average: 0.31, 0.52, 0.62
11:23:01 up 241 days, 19:06, 3 users, load average: 0.11, 0.42, 0.58

This method should work on most flavors of Linux, including Ubuntu, CentOS, Red Hat, Debian, etc.

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The story piqued my interest as well, and not just because it was played and replayed on every news station for the next week. No, it grabbed my attention for another reason — many people don’t know this, but I used to be a chemist.

“Liquid explosives?” I said. “That they mix up right there on the plane?” Hmmmm. Sounds kinda fishy to me.

There is nothing inherently fishy-sounding about liquid explosives themselves – in fact, one of the best known explosives of all time, nitroglycerin, is a liquid. But the thing is, first, you need to slowly and carefully mix nitroglycerin, something that you bloody well can’t do on a plane. Secondly, and even more importantly, nitroglycerin and other liquid explosives are fairly unstable and can be detonated by good hard rap, so they’re not exactly something that you’d likely be walking around with.

I just can’t imagine what the terrorists were planning on brewing up 1) on a plane, 2) without a heat source / without access to ample ice 3) that would release enough energy to do anything more than start a fire.

I found an article at the Register that outlines just how unlikely a scenario this is:

• First, you’ve got to get adequately concentrated hydrogen peroxide. This is hard to come by, so a large quantity of the three per cent solution sold in pharmacies might have to be concentrated by boiling off the water. Only this is risky, and can lead to mission failure by means of burning down your makeshift lab before a single infidel has been harmed.
• The remaining ingredients, acetone and sulfuric acid, are far easier to obtain, and we can assume that you’ve got them on hand.
• Take your hydrogen peroxide, acetone, and sulfuric acid, measure them very carefully, and put them into drinks bottles for convenient smuggling onto a plane.
• Don’t forget to bring several frozen gel-packs (preferably in a Styrofoam chiller deceptively marked “perishable foods”), a thermometer, a large beaker, a stirring rod, and a medicine dropper. You’re going to need them.
• Once the plane is over the ocean, very discreetly bring all of your gear into the toilet. You might need to make several trips to avoid drawing attention.
• Once your kit is in place, put a beaker containing the peroxide / acetone mixture into the ice water bath (Champagne bucket), and start adding the acid, drop by drop, while stirring constantly. Watch the reaction temperature carefully. The mixture will heat, and if it gets too hot, you’ll end up with a weak explosive. In fact, if it gets really hot, you’ll get a premature explosion possibly sufficient to kill you, but probably no one else.
• After a few hours – assuming, by some miracle, that the fumes haven’t overcome you or alerted passengers or the flight crew to your activities – you’ll have a quantity of TATP with which to carry out your mission. Now all you need to do is dry it for an hour or two.
• Once dry, TATP is relatively easy to detonate. But you must make enough of it to crash the plane, and you must make it with care to assure potency. While it’s true that a slapdash concoction will explode, it’s unlikely to do more than blow out a few windows. At best, an infidel or two might be killed by the blast, and one or two others by flying debris as the cabin suddenly depressurizes, but that’s about all you’re likely to manage under the most favorable conditions possible.

Heh.

Folks, I admit, I’m no explosives expert. But from what I know about chemistry, and as this article demonstrates, this seems like a rather unlikely plot.

Link: How to make Nitroglycerin

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