Networking

HTTP GET vs POST

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A very useful table from w3schools

GET POST
BACK button/Reload Harmless Data will be re-submitted (the browser should alert the user that the data are about to be re-submitted)
Bookmarked Can be bookmarked Cannot be bookmarked
Cached Can be cached Not cached
Encoding type application/x-www-form-urlencoded application/x-www-form-urlencoded or multipart/form-data. Use multipart encoding for binary data
History Parameters remain in browser history Parameters are not saved in browser history
Restrictions on data length Yes, when sending data, the GET method adds the data to the URL; and the length of a URL is limited (maximum URL length is 2048 characters) No restrictions
Restrictions on data type Only ASCII characters allowed No restrictions. Binary data is also allowed
Security GET is less secure compared to POST because data sent is part of the URL

Never use GET when sending passwords or other sensitive information!

 POST is a little safer than GET because the parameters are not stored in browser history or in web server logs
Visibility Data is visible to everyone in the URL Data is not displayed in the URL
Setup

Simple SSL configuration for Apache-Tomcat

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For the official instructions (Tomcat 8), read this page

The following instructions are for development servers only:

Step 1: Create a keystore file to store the server’s private key and self-signed certificate:

For Windows:

"%JAVA_HOME%\bin\keytool" -genkey -alias tomcat -keyalg RSA

For Unix/Linux:

$JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA

You will be asked for various information. Remember the password you typed at this step.

At the end of the procedure, keytool will create a file named “.keystore” to your home directory. By default it is hidden. This file should be moved to Apache-Tomcat home directory and can be renamed (eg to “keystore”).

Step 2: Disable APR:

Edit server.xml and comment out the following line:

<!--
    Listener
    className="org.apache.catalina.core.AprLifecycleListener"
    SSLEngine="on"
/-->

Step 3: Activate the SSL connector

Edit server.xml and add (or uncomment and modify) the following lines:

<Connector 
    port="8443" 
    SSLEnabled="true" 
    protocol="org.apache.coyote.http11.Http11NioProtocol"
    maxThreads="150" 
    scheme="https" 
    secure="true"      
    keystoreFile="keystore" 
    keyAlias="tomcat"
    keystorePass="12345678"
    clientAuth="false" 
    sslProtocol="TLS" />

You will have you replace “12345678” with your password.

You will also have to replace “keystore” with the full path to the keystore file generated at Step 1.

Step 4: Restart Tomcat

Do not forget to restart Apache-Tomcat

 

 

Hardware, Windows

Audio staggering in Windows 10

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Before upgrading to Windows 10, check if there are drivers written for your hardware specifically for Windows 10. You should definitely check that drivers exists for your network card and your audio card.

This is because Windows 10 suffer from the same (and important) problem Windows 8 suffer: High DPC (deferred procedure call) latency. If the drivers do not work properly you may have high DPC latency, which may result to audio staggering, lag, clicks, drop outs even if your CPU does not reach 100%. This means that there is a high chance you won’t be able to playback movies flawlessly while using the network card! What a break dealer!!!

You can verify if your system suffers from high DPC latency by using LatencyMon. To learn what DPC latency is read this article.

If there is no Windows 10 driver for your network card, the easiest thing to do is not to upgrade to Windows 10 !!!

Now, what do we do if we have upgraded to Windows 10 and do suffer from undesired DPC latency? There are numerous solutions in the net. Most of which do not work.

Imho, You should complete the following steps by that order. If the problem is solved at any point, you don’t have to (and better not to) do the rest of the steps.

Step 1: Update your system.

Step 2: If possible, remove 3rd party antivirus and firewall software.

Step 3: Remove any software you don’t need (you should do that anyway)

Step 4: Update all drivers to latest version.

At this point, if the problem persists then most probably one of your drivers is faulty or not completely compatible with Windows 10. You can find which by using LatencyMon but you can bet it is the network/wireless driver.

The only thing you can do is rollback to an older version. So there are two more steps to do:

Step 5: Verify that the driver installed is for the correct hardware and not just for the correct hardware family. If your card is named 6200 then your driver should be for 6200. Anything else like 6201, 6205, 6300 is not acceptable.

Step 6: Find the proper driver for Windows 7 and install it

If the last step does not work, then you can try other drivers from the same family.

Lastly, if the problem still persists then there are two more steps but they are a long shot:

Step 7: Optimize BIOS :

Important settings to disable and may help are:

  • Virtualization
  • High precision timer

Step 8: Update the BIOS

Personally, I don’t think the last step helps. But many people claim it does, so you have nothing to lose.

 

Networking

Recommended settings for 802.11n

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Here are the official recommended settings for Wifi 802.11n from Intel:

Property Value
802.11n channel width for band 2.4 Auto (not in 20 MHz only)
802.11n channel width for band 5.2 Auto (not in 20 MHz only)
802.11n mode Enabled
Fat channel intolerant Disabled
Roaming aggressiveness Medium (or less)
Throughput enhancement Disabled
Transmit power Highest
Wireless mode 802.11a/b/g
HT mode VHT mode

On the wireless router, check the following options:

Property Value
Auto channel scan Enable
802.11 mode Use 802.11n only
Channel width 40 MHz

References:

https://www.intel.com/content/www/us/en/support/network-and-i-o/wireless-networking/000005544.html

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