Exercises, examples and other material relating to training module A606. This topic is presented on public courses
| Articles and tips on this subject | updated |
| 4491 | Web Server Admin - some of those things that happen, and solutions
The techincal "Buck" with our web sites stops with me - and any little admin issues that come up while I'm away on holiday need to be sorted - and of course Murphy's law states that a problem will always happen at the worst possible time. And so it's been with a couple of never-before issues that have ... | 2015-05-10
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| 4404 | Which (virtual) host was visited? Tuning Apache log files, and Python analysis
We host a number of domains on our main server, and in order to avoid fragmentation of log files, we keep a sinle composite log. Rather than use a standard logfile format henceforth, I've changed the second field to carry the virtual host name accessed for the request, as that was missing up until this ... | 2015-01-23
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| 3027 | Server logs - drawing a graph of gathered data
You can log pretty much any server data on a Linux or Unix system at regular intervals using a crontab job that adds a line onto the end of a file. That crontab job could be as simple as a shell command, or it could be a bash or perl script (the two most natural languages to choose for such a task) or ... | 2014-09-29
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| 4307 | Identifying and clearing denial of service attacks on your Apache server
If ... ..... .... I ..... ..... were ...... ... ... ... to . ...... . write .... .... .... . a ... ...... ... ..... sentence, .. ... but ...... .. drip ...... . ..... ...... ... the ..... ... .. ...... ...... words . . .. out ..... .. ...... ..... . slowly ..... ... ...... with .... ... ..... ... long ... | 2014-09-27
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| 3984 | 20 minutes in to our 15 minutes of fame
Well - in the week of 7th January, we were on Channel 4 every day at 5 p.m. as we visited (as owners of Well House Manor) three other accommodations around the UK, met with their owners, and competed for the "Best Value B&B of the week" prize. Watched by (third party data) around 950,000 people. ... | 2013-01-26
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| 3974 | TV show appearance - how does it effect your web site?
We were told to expect our web site to get busier when we appeared on "Four in a Bed" on Channel 4, but no numbers were put onto what we might expect. Would it be a doubling of traffic? More than that, or less? It was suggested we ensure the site was robust for further traffic though, suggesting that ... | 2013-01-19
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| 3670 | Reading Google Analytics results, based on the relative populations of countries
We get a lot of traffic on our web site, but where does it come from? Our raw log files tell us a great deal, but there is just so much data there it's very hard to manage, so we're using Google Analytics as well. I'm delighted to read reports of xxx visitors from Sweden, yyy from Romania and zzz from ... | 2012-03-31
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| 3554 | Learning more about our web site - and learning how to learn about yours
There are quite a number of tools out there which will give you statistics about your web site - and quite a lot of people who will tell you various statistics about yours and theirs. But there's "Lies, Damned lies and statistics" according to Benjamin Disraeli. How do you really understand your traffic ... | 2011-12-17
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| 3491 | Who is knocking at your web site door? Are you well set up to deal with allcomers?
Anyone who advertises a public facing web server / web site is telling everyone about a door to their resources ... and even those people who have web sites which they don't advertise are likely to be talked about and so discovered by a potentially wide audience. So it's rather important for the people ... | 2011-10-21
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| 3447 | Needle in a haystack - finding the web server overload
*Something* on our web server has been causing the loading to rocket a couple of times a day recently, and it's been a bit of a problem to find out what that something is. Rather like searching for a needle in a haystack - except that when you find something that you think may be the problem, you can't ... | 2011-09-18
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| 3443 | Getting more log information from the Apache http web server
The Apache httpd server is preconfigured when you download it to define common and combined logging formats - and those are the standards accepted by so many tools. But there's so much more information available if you choose to log it. In order to get a better understanding of metrics of the traffic ... | 2011-09-16
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| 3087 | Making the most of critical emails - reading behind the scene
You can't please 100% of the people 100% of the time. So if you have a public facing website with anything like a reasonable number of visitors (we had accesses from over 16,000 different IP addresses in the last 24 hours), you're bound to have a few visitors who aren't totally delighted with what the ... | 2010-12-16
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| 3019 | Apache httpd Server Status - monitoring your server
Do you want to know how your Apache httpd web server is running? The Server Status tool - a standard module supplied with the httpd daemon - can give you a lot of information, but by default it's turned off.
Turning it on ...
A work of caution before you turn it on. You do NOT want this to be world ... | 2010-10-28
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| 3015 | Logging the performance of the Apache httpd web server
Apache's mod_status allows you to take a look at how your Apache httpd server is running - you can see a snapshot of some basic stats of the server, and also the current status of each of the threads. There are two options that you can apply to the URL as you look at the page - a refresh option to cause ... | 2010-10-26
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| 1237 | What proportion of our web traffic is robots?
We welcome search engines to our site - to index our content and point their visitors back to us where appropriate, but such search engines are a means to an end and not an end in themselves. How much traffic to our web site is true visitor traffic, and how much is automata? An interesting pointer is ... | 2010-01-05
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| 1796 | libwww-perl and Indy Library in your server logs?
Here are some sample lines from our server logs ... and I don't like the look of them!
from 195.39.5.203 - Moravskoslezsky Kraj, Czech Republic [1000 miles] - libwww-perl/5.805
.net: /resources/recents.html/plugins/safeh...ms_files/images/id.txt???//index ... 16:44:24
from 91.187.115.253 - Vojvodina, ... | 2008-09-13
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| 1780 | Server overloading - turns out to be feof in PHP
From the manual page on feof:
Warning - If passed file pointer is not valid you may get an infinite loop, because EOF fails to return TRUE.
From a script on our server:
while (1) {
$nlines ++;
$line = fgets($fh,1024);
if (feof($fh)) break;
OOps! ... the file that's ... | 2008-09-01
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| 1761 | Logging Cookies with the Apache httpd web server
An interesting question that came up yesterday - can we extend Apache httpd's logging to include details of cookies sent to the server? The answer is yes, and overnight I have done a little testing.
Let's say I want a log file with records like this:
203.126.136.220 [20/Aug/2008:07:39:25 +0100] ... | 2008-08-21
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| 1656 | Be careful of misreading server statistics
Here's a mystery for you.
Background
Over the past weekend, I was "fighting" server outages on another computer where - about once an hour - the httpd daemon appeared to be running away in some sort of hole or denial of service attack. Tricky one to find, as the temporary fix I had in place was in ... | 2008-05-28
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| 1598 | Every link has two ends - fixing 404s at the recipient
"They have printed the wrong link." Thus starts a frustrated post on the Save the Train web site, worried that a link in the local newspaper to our support pledge page ends up at a "404". And, yes, they have dropped the newspaper a line too, hoping to catch them before the online edition goes "printed".
But ... | 2008-04-03
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| 1503 | Web page (http) error status 405
Running his first Java Servlet today, one of my delegates reported an HTTP status 405 from his code when he tried to browse to it. A new one on me ... I am used to a good number of other return codes, but hadn't seen this before.
It turns out that the cause was the lack of an appropriate doGet method ... | 2008-01-14
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| 376 | What brings people to my web site?
How busy is your web site? How do people find it? Where do they arrive from? If you have access to your log files and they're using the "combined" format that tells you about the referer, you'll have that information - but hidden deeply in what's likely to be a huge file.
Here's a little bit of PHP ... | 2006-06-05
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Configuring the access and error logs.
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