Miscellaneous Knowledge

Around mid december, I noticed that traffic for my Left 4 Dead Servers page dropped sharply – from 100 unique visitors a day to 5, at most.

Traffic Graph for www.l4dservers.net

Most of my traffic comes from search engine referrals, so to have a drop off like this must have something to do it Google.

Cue Google’s Webmaster Tools, a handly place for you to view all statistics about your site. On their diagnostics section I was getting a lot of “Network Unreachable” errors on the robots.txt. Basically, Google couldn’t access my site to read the robots.txt – nothing wrong with the actual robots.txt at all, it was a web server problem. After having a look around, I came across some information on diagnosing the issue, no help from Google itself on this matter of course. The information listed here indicated that certain software was blocking google for making too many requests the to the server, in a DoS attack fashion. This site is hosted on reseller hosting, however it shares the machine with a lot of other websites. In which case, Google has been accessing many sites on this server generating a high number of requests. Therefore, the software on the machine automatically blocked Google falsely beleiving that it was attacking sites on the machine.

This blog was also hosted on this reseller account, and traffic figures showed a similar decline. I’ve recently bought a dedicated cPanel server to replace the reseller and moved the blog onto there – bingo! This blog now appears back in search engine listings. If we look at Google’s Webmaster Tools, we can see the amount of pages crawled by it.

Google Crawl Statistics for Miscellaneous Knowledge

Right after moving it off the reseller hosting and onto the server, loads of pages are instantly and successfully crawled. The blog is back in the Google index.

www.l4dservers.net is still pending move to the new hosting, but I expect to see similar results once I have completed the move, just waiting on the DNS to be updated for it.

So what can you do if you experience this issue? First, read this excellent article and make sure that your lack of Google listing isn’t your fault. If you are not at fault, contact your hosting provider and point them to the article, ask them if they have any firewalls that block multiple requests such as the Googlebot. I would also highly suggest signing up to Google’s Webmaster Tools to help diagnose any problems Google has accessing your site. While they where not particually helpful in this incident, it did help to get me started on the diagnosis. Not only this, but it allows you to submit sitemaps which vastly improve your ranking and help make sure that every page is in Google’s index. Sitemaps are checked very often and any new URLs are quickly crawled helping you get any content into Google quickly.

From the more technical side, this article might be of interest. It details how ConfigServer Firewall might be a culprit in this.

Days are always long, you can’t fit 86400 into a short.

If you don’t get the joke, don’t worry – you’re not missing much.

During the last week, it seems the AC adapter for my Vostro 1500 Laptop that I purchased 7 months ago has developed a fault meaning that the AC adapter is not detected by the laptop. It still charges and powers the laptop fine however on every boot it makes a very loud beep and requires you to strike F1 to ignore the warning. In addition, the performance of the laptop is reduced to a minimun.

After looking around, it seems the AC adaptor contains a proprietary 1-wire device that transmits a serial number to the laptop. This is meant to prevent you from using 3rd Party adapters, only using Dell’s own adapters. However, the chip and communications are very prone to breakage, which is what seems to have happened in my case. This is not an isolated incident.

Thankfully, it’s still in warranty. A replacement is arriving tomorrow. Congratulations to dell on getting a replacement to me quickly, but I am disappointed that they have made the laptops only compatible with their own power adapters by use of the proprietary 1-wire device inside the power adapter.

Interleaving is part of ADSL, a protocol used to connect to the internet over phone lines. This can also be called DSL for those of you in the US.

Interleaving is a technology that increases the stability of the line, at the expensive of latency. Simply put, while it is activated your line will not disconnect as often but will have a slightly higher ping. For most people this is fine, however Gamers and users of a VOIP service or anything where latency is crucial want their ping as low as possible.

Most ISPs turn on interleaving by default, if your line is relatively stable then you can request them to turn it off. Some ISPs will not comply, but most will happily do so. My new ISP ADSL24 (who are a reseller for Entanet) allow you to control interleaving on the line. I requested that it was turned off, and my ping decreased by 10ms. Game on!

Not only this, but my line is just as stable. If you are a gamer or VOIP user, ask your ISP to turn off Interleaving to improve your latency.

PHORM PROHIBITED

The contents of this site, and communications between this site and its users, are protected by database right, copyright, confidentiality and the right not to be intercepted conferred by section 1(3) of the Regulation of Investigatory Powers Act 2000. The use of those contents and communications by Internet Service Providers or others to profile or classify users of this site for advertising or other purposes is strictly forbidden.

Owned. I’ve left BT over their illegal privacy invading Phorm system. I will not have my privacy invaded to increase the bonuses of overpaid BT executives and shareholders – I suggest others do the same.

Recently, I needed to turn on magic quotes for a customer on our web hosting. Now, our web hosting is not actually hosted by me, rather I purchase a reseller package. This allows me to offer cPanel access without having to spend an absolute fortune on it. However, it means I don’t have access to the php.ini and hence can’t turn on magic quotes.

Now, I wouldn’t want it on anyway (and it’s quite bad apparently) so how could I enable it just for this customer?

The answer? .htaccess . I have always thought .htaccess as just a file that controls access, not an entire config. Adding the following line

php_flag magic_quotes_gpc on

Turns Magic Quotes on for that user. Awesome.

There is a lot more that can also be configured via the .htaccess too, such as extension handling and more. Have a look into it if you’re intested.

Edit: Yeah, it’s down again and has been for some months. Perhaps some day i’ll get it back up again. However, feel free to put your own one up – it’s an awesome game mode.

After months of neglect, i’ve updated and started the Garry’s Mod Prop Hunt server again. It’s still at 4 players as before, but if it’s popular i’ll raise that limit.

In Prop Hunt, there are two teams, Hunters and Props. The job of the Props is to become a prop (by pressing E while looking at it) then blend in somewhere. Hunters have to find these false imposter props and kill them. However, they loose 5HP for every real prop they shoot, so make sure you know what you’re shooting. The latest update allowed props to say a series of taunts to tease those (sometimes dumb) hunters!

The map is still just cs_office as I think this has the best number of props and is small enough so that you can actually find the props (sometime).

So, if you’ve got Garrys Mod, come join the fun at 193.200.158.235:27028. If you’ve got any suggestions relating to the server, let me know.

I run my own home mailserver for two reasons, because I enjoy setting up systems and because I can. However, having just 1 mailserver introduces some problems. While according to the RFCs, sending servers are to keep sending failed mail for some time, they often dont. Consequently, if my server goes offline, loss of internet, reboot etc, I often loose a lot of email.

The solution to this is to have a Secondary MX (Mail Exchanger). This is another email server that will also accept email for your domain and keep trying to forward it to your Primary MX, forever. So, when my server comes back up, the email gets sent and not lost.

For a while, i’ve been using DNS Made Easy for my Secondary DNS and MX (don’t forget a secondary DNS, otherwise they can’t find out about your Secondary MX if your Primary DNS is down!). It worked, but not very well and recently i’ve noticed that i’ve been loosing email. DNS Made Easy have no information about their service status either, you have to trust that it’s working.

So, after searching for a while, I came across RollerNet. They provide many serivces, Primary/Secondary DNS/MX etc. I got a free account with them and was amazed at their quality of service. Most importantly, they give detailed logs of your MX status, such as mail received, mail in queue and the option to force-initiate a transfer of mail to your Primary MX. On top of that, they have all the usual spam filtering using the major blacklists, so no false-positives. Unfortunately, their free account has a limit of 50 messages a day (and many spammers target the Secondary MXes) so i’m now exceeding my message limit. No harm done though, i’m really impressed by their quality of service and going to take out a proper subscription. Good job RollerNet!

Update: I’m no longer recommending Google Checkout after they raised their fees to be equal to that of PayPal. Google’s only real advantage was their low transaction rates, now that it’s at parity it does not make sense to continue using them. See here for more information. I leave the article below for referrence on what was once a great service.

Customers of my game server business may have recently noticed that we’ve added a new payment method, Google Checkout. There have been many reasons driving this, both ones that benefit customers and me.

First of all, from the customer side, Google Checkout is much simpler to use and offers a lot more control over payment history. We’ve had a few customers who have had a bad experience with PayPal and refused to use it. However, unlike PayPal, Google Checkout can only accept a Credit/Debit card as a funding source, so you can’t pay using existing funds or a bank account. However, we found that most people used a Credit or Debit card anyway.

On our side however, it’s even better. While we have to hand-process each order (charging the card etc) the way is done is very good. Plus, we also get a lot more control over the order and like it is for the user side, the history is excellent. There is also the added benefit of having the Google Checkout badge on your AdSense results, which helps make your ad stand out.

One major factor that many might consider is fees. PayPal’s base rate is 0.25p + 4%. This can quickly mount up, with a £24 payment having over £1 in fees, and if you have micropayments it gets even worse. Google Checkout however has 0.15p + 1.5%, faw lower. It doesn’t stop there however, if you advertise using their AdWords service you get £10 worth of sales processed for free for every £1 in advertising you spend. So say you spend £10 on AdWords a month, that gives you £100 of sales processed for free (note: not £100 worth of fees). So the savings are even greater! (More lower prices I can pass on to users)

Perhaps the most interesting bit for us however is that payments are initated to our bank account daily. Unlike PayPal, where you have to get £50 first before you can withdraw. That’s upto £50 that you are not earning interest on and is completely under PayPal’s control.

I will however keep offering PayPal, while Google Checkout is far better when you compare it it has the disadvantage of being unfamiliar to users and not supporting Bank Account funding, so as not to alienate parts of my userbase i’m running both but recommending Google Checkout.

Update: Got an email the other day from Google saying that I didn’t qualify to have the Google Checkout badge on my AdWords adverts. Apparently, they couldn’t find the badge, so they must just quickly check through. I emailed them back and they checked again and found it (you have to fill out an order form). While the AdWords badge isn’t particually important, it helps you stand out from competitors.

If you’ve ever set up MediaWiki, you will probably know how difficult it is to get equations (or LaTeX rendering / math tags) working. Under windows, it requires a lot of tweaking, ImageMagick support, a full LaTeX install and in quite a few cases fails to work. While trying to get equation rendering working on my personal (read, private!) wiki, I came across an interesting solution to this problem. Simply put, it is in extension which interprets <tex> tags and then sets the image URL to that of an image generated by a CGI-Script on another page. This means that no LaTeX or ImageMagick support is needed on the localhost.

The full details of how to get this working are documented here. It is very simple to set up, with the only drawback being that you have to use <tex> tags instead of <math> tags.

If you are interested in the script itself, perhaps to use it for something other than a Wiki, you can visit the creator’s site here. If you have a large wiki or other project however, it is recommended that you host the CGI script yourself to reduce the load on the server that provides this free LaTeX equation rendering.