SSH command:

netstat -lptu

However, getting a list of open ports after IPTABLES and your Firewall have done their job requires a Port Scan. To get the fairest results this needs to be done from a different machine (depending on your IPTABLES/Firewall config, and what it is you’re trying to test).

SSH command:

nmap 192.0.32.10

You might also find this useful.

SSH command:

nmap -sS -p0-65535 -P0 -T4 --osscan_limit --osscan_guess --host_timeout 15m --max-retries 0 --min_parallelism 100 --max_parallelism 500 -O -oX -V 192.168.1.1

First, lets look at the maths. For those in the know, we’re essentially calculating the difference in the hypotenuse. Whichever result returns the lowest number from our data set will be the closest.

The number we need is the Square Root (√) of:
(firstLongitude-secondLongitude)*(firstLongitude-secondLongitude)
+
(firstlLatitude-secondLatitude)*(firstLatitude-secondLatitude)

Obviously, this number is useless if we have only two locations (and then we wouldn’t be interested in which was the closest anyway!), so we would loop this equation, changing the second lat/long for each location, to figure which is nearest.

In PHP we can do that like this:

<?php
 
$value = sqrt((($firstLongitude-$secondLongitude)*($firstLongitude-$secondLongitude))+(($firstlLatitude-$secondLatitude)*($firstLatitude-$secondLatitude)));
 
?>

Remember, we’d need this to loop to be useful.

And in MySQL we’d select the data like this:

ORDER BY SQRT
(((fLongitude-sLongitude)*(fLongitude-sLongitude))
+((fLatitude-sLatitude)*(fLatitude-sLatitude))) 
ASC LIMIT 1;

Hopefully this will help you get the ground work in place to make a decent start.

Constantly jumping into the Control Panel to change my network settings when I change subnet was taking awhile, and another NIC isn’t an option here, so I made these quick .bat files that I can run when I need to update things

Set-IP-DHCP.bat:

netsh interface ip set address name="Local Area Connection 2" dhcp
netsh interface ip set dns name="Local Area Connection 2" dhcp

Set-IP-Static.bat:

netsh interface ip set address name="Local Area Connection 2" source=static addr=10.99.88.3 mask=255.255.255.240
netsh interface ip set dns name="Local Area Connection 2" source=static addr=10.99.88.5  
netsh interface ip add dns name = "Local Area Connection 2" addr = 10.99.88.5

They wanted part of this website to only be accessed by one domain, and create a 404 error otherwise. I achieved this with a quick URL Rewrite:

Apache Conf:

RewriteCond %{SERVER_NAME} !^websubdomain\.somedomain\.co\.uk
RewriteRule (.*) - [R=404,L]

Cron command:

0 7 * * *   wget -O - -q -t 1 http://www.example.net/path-to-file/file.php

or we can use Lynx if need-be.

Cron command:

0 7 * * * /usr/bin/lynx --source http://www.example.net/path-to-file/file.php

If the file isn’t on the net, you can also run it by calling PHP direct…

Cron command:

0 7 * * * /usr/local/bin/php -q /htdocs/www/x.php

Remember to check your path to PHP. Hopefully this will help someone looking for the same thing.

Apache Conf:

RewriteEngine On
RewriteRule ^(.*/)?\.svn/ - [R=404,L]

This will give you a 404 error, and show you the Server’s 404 page. If you set this rule locally in a Virtual Host, you can show the error doc for that custom virtual host.

You could of course modify this to return 403, or any error number you like.

backup-db:

#!/bin/bash
 
#Author : Gavin Pearce @ GavinPearce.com
#Date : 2010-04-14
#Purpose : Backup all databases on one server to another server, and record to log file
 
FILENAME=DB`date +%F`.sql
mysqldump -u root -pyourpassword --all-databases > /var/backups/$FILENAME
echo "---------------------------------------------------------">> /var/backups/log
echo "BACKUP JOB: "`date +%F-%H:%M:%S ` >> /var/backups/log
rsync -ave ssh /var/backups/ otherserveruser@192.168.1.1:/var/backups2/ >> /var/backups/log
echo "---------------------------------------------------------">> /var/backups/log

To have RSYNC work, you will need to setup Key Based logins between the two servers. Or you could use SCP on this line …

You will also need to check:

1. The username/password for MySQL;
2. The path you export the initial Database Export/Dump to;
3. The username of the user on the other server you are RSYNCing with;
4. The IP of the  other server.

Then add this script to cron to run when you need it. Don’t forget to give it execute permissions.

Cron:

1 23 * * * root /usr/local/bin/backup-db

Add the following to the bash profile file for each user you want to see the message. You can find the file in their home directory.

.bash_profile:

fn=/home/quotes.txt
cnt=$(wc -l $fn)
lns=${cnt:0:2}
if [ "$lns" = 0 ]; then
  rnd=1
else
  let "lns += 1"
  rnd=$(expr $RANDOM % $lns)
  let "rnd += 1"
fi
echo   
sed -n ${rnd}p $fn
echo

Create a file called quotes.txt, put each quote on it’s own line, and upload to a location to which all users have access. I use /home/quotes.txt.

Behold some great quotes as you login!

I’ll leave you with a few of my favourite to get you start:

“The only people who have anything to fear from free software are those whose products are worth even less.” – David Emery

“640K ought to be enough for anybody.” – Bill Gates 1981

“Computers are getting smarter all the time. Scientists tell us that soon they will be able to talk to us. (And by ‘they’, I mean ‘computers’. I doubt scientists will ever be able to talk to us.)” – Dave Barry

“Computers are useless. They can only give you answers.” – Pablo Picasso

“Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.” – Eric Raymond

Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen. – Winston Churchill

Here’s the script we use to do this:

welcome-msg:

#!/bin/bash
tod='morning'
hour=$(date | cut -c 12-13)
if [ $hour -gt 11 ]; then
	tod='afternoon'; 
fi
if [ $hour -gt 17 ]; then
	tod='evening'; 
fi
echo -e "\nGood" $tod "and welcome to SERVERNAME.\n\n" > /etc/motd

Upload and give it execute permissions.

Add to Cron:

1 * * * * root /usr/local/bin/welcome-msg

Enjoy!