Flashback To 2000 – DIY WiFi Point To Point Link

Beginning of a fascination

Since early childhood I was fascinated by electronics, electrics and RF. I still remember getting my first CB (citizens band radio) when I was 12 back in 1988. It was amazing talking to someone on the other end via radio waves, I was intrigued by how it all worked and how to get better range.

Fast forward to 2000, I landed a job as an IT Co-Ordinator at a logistics company.  The logistics company had a very large warehouse filled with WiFi access points for the WiFi enabled hand scanners they used to scan boxes. The WiFi access points were 802.11b only with supported rates of 1Mb/s and 2Mb/s.

It was the coolest thing being able to send data wirelessly, I needed to learn more! I wanted to know how I can connect two buildings via this cool new technology. At that stage I knew a lot about RF in the lower frequencies, 27MHz to 433MHz but I had no knowledge of microwave frequencies.

I knew that if I wanted the signal to go further I needed directional antennas. I proceeded to build and test a "cantenna" out of a "Pringles" can. The results were way better than with the included standard omni directional rubber duckys. In the next few years I built and tested various Yagis, Flat panel, dish antennas and even a circular polarised helical antenna.

Come 2003 and I bought a set of Linksys WRT54G's and 24dbi grid antennas for a 14km point to point link to a friend for lan gaming. For the WRT's to communicate they had to connect in WDS mode (wireless distribution system). The standard Linksys firmware did not have this function and a custom firmware had to be loaded. The first firmware I tried was Sveasoft's Linksys firmware, I also later experimented with OpenWRT but finally stuck with DD-WRT.

I recall the 14km  link at that stage had a very good signal on 802.11B/G rates, -65dbm got us connected at 48Mb/s-54Mb/s link speed but we never saw great throughput. On average we were seeing 1Mb/s on large file FTP transfers. The WiFi link wasn't reliable either with a lot of time outs and disconnects. The problem was that none of the available firmware knew about long link distances. Later on this function was added and speeds improved to 2.6MB/s on large file FTP transfers.

Above: 14KM point to point WiFi link to a friend to be able to play Lan games.

 

Later on I got access to a local HAM radio amateur club repeater tower and added  a custom built base station using Mikrotik Router OS on a Pentium 4 computer with a bunch of Wistron Neweb CM9 802.11B/G cards. I even built my own sector antennas.

How To Get BitLocker Recovery Key From Microsoft Account

If BitLocker drive encryption was used to encrypt the contents of a drive the drive will be unusable in another system until the BitLocker 48 Digit recovery key is supplied.

What is BitLocker?

BitLocker Drive Encryption is a Microsoft Windows data protection feature that encrypts hard drive contents, BitLocker integrates with the operating system and addresses the threats of data theft or exposure from lost, stolen, or inappropriately decommissioned computers.

What is a BitLocker recovery key?

BitLocker recovery key is a unique 48-digit numerical password that can be used to unlock your system if BitLocker is otherwise unable to confirm for certain that the attempt to access the system drive is authorised.

Why is Windows asking for my BitLocker recovery key?

Windows will require a BitLocker recovery key when it detects a possible unauthorised attempt to access the data. A typical example is when a hard drive from one computer is moved to another computer, when trying to access the drive contents.

BitLocker provides extra security that is intended to keep your data safe and secure. This can also happen if you make changes in hardware, firmware, or software which BitLocker cannot distinguish from a possible attack. In these cases, BitLocker may require the extra security of the recovery key even if the user is an authorized owner of the device.

How can I find my BitLocker recovery key?

When activating the BitLocker feature you will be given options on where to save the BitLocker recovery key:

-Save to your Microsoft account

-Save to a file

-Print recovery key

As the Save to a file and print options are straight forward I want to focus on retrieving the BitLocker recovery Key from Microsoft.

Recover BitLocker Recovery Key From Microsoft

To retrieve your BitLocker 48 digit recovery key click on either of the following links:

https://account.microsoft.com/devices/recoverykey

https://onedrive.live.com/recoverykey

After clicking on the link sign in to your Microsoft account and voila, your key should be there.

 

Fix Outlook Error “Your Mailbox Has Reached Its Maximum Size Limit”

Microsoft Outlook emails are stored in a single database file with an extension of .ost or .pst. Various Outlook versions have different .ost/.pst storage limits. When the .pst or .ost file reaches it's storage limit you will get an error "Your mailbox has reached its maximum size limit at which you cannot send or receive any more content. Empty your deleted items folder from Outlook or delete messages from your mailbox to create more space." This can be fixed...read on.

What is an .OST or .PST file?

Outlook Data Files (.ost) are used when you have an Exchange account and want to work offline or use or use the default Cached Exchange Mode. This type of data file is also used for accounts that you set up with the Outlook Connector for Outlook.com (formerly Hotmail). Outlook Data Files (.ost) are always copies of items that are saved on a mail server and don’t need to be backed up like Outlook Data Files (.pst).

Outlook Data File (.pst)

An Outlook Data File (.pst) contains your messages and other Outlook items and is saved on your computer. When you use POP accounts, all of your email messages from your mail server and save them on your computer.

Note: In Outlook 2013 and earlier versions, IMAP accounts also used an Outlook Data File (.pst). In Outlook 2016 and Outlook for Microsoft 365, IMAP accounts use Offline Outlook Data Files (.ost).

Offline Outlook Data File (.ost)

Most other account types, such as IMAP accounts, Microsoft 365 accounts, Exchange accounts, and Outlook.com accounts use an Offline Outlook Data File (.ost) file to store a synchronized copy of your mailbox information on your local computer.

.OST & .PST Limits

The various Microsoft Outlook versions come with specific data storage limits. Outlook 2010, 2013, and 2016 have maximum limits of 50GB. Whereas, Outlook 2003 and 2007 have a maximum data storage limit of 20GB.

How To Fix Outlook Error "Your mailbox has reached its maximum size limit at which you cannot send or receive any more content. Empty your deleted items folder from Outlook or delete messages from your mailbox to create more space."

You have two options:

1)delete or archive email messages or

2)increase the size limit of the .ost/.pst file.
Option 1 is self explanatory, but what if you prefer option 2?

Adjust the .OST or .PST file size limit in Windows Registry

For this option we will have to create Windows registry entries.
Note: If you have are not familiar with editing the registry then this option is NOT for you. If you feel brave and what to go ahead then make a BACKUP of your registry first.

Before you start, make sure Outlook is closed.

Note: Check your version of Outlook and match it to the option below.

Click Start, click Run, type Regedit, and then click OK.

In the left pane, expand the following registry key based on your version of Outlook:

For Outlook 2016

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook

For Outlook 2013

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook

For Outlook 2010

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook

For Outlook 2007

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook

For Outlook 2003

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\11.0\Outlook

Right click Outlook, point to New, and then click Key.
Type PST, and then press ENTER. (The screen shot for this step is listed below).

 

Right click PST, point to New, and then click DWORD value. (The screen shot for this step is listed below).

Type MaxFileSize, and then press ENTER twice.

In the Edit DWORD Value window, choose Decimal and type the value in the Value data box, and then click OK.
Note 1GB=1*1024*1024*1024byte; 1MB=1*1024*1024byte; 1KB=1*1024byte, the example below is for a 100GB size limit with a 95GB warning limit.


Edit DWORD Value window

Repeat above steps to create another DWORD MaxLargeFileSize.

Repeat steps above to create another DWORD WarnLargeFileSize, and then close the registry.

Close Registry Editor

You can now open Microsoft Outlook.

 

 

Extend WiFi To An Outdoor Office Or Shed

Getting internet to an outdoor building isn't always as straight forward as it should be. WiFi is a low output power and high frequency medium that does not penetrate well or reach far. In order to make WiFi effective it must be in close proximity.

Network cable isn't always a solution either as ethernet cable length is limited to max 100 meters. So how are you supposed to get internet to an outdoor shed /office?

How To Extend WiFi/Internet to a shed or outdoor building

If the outdoor building is within 100 meters then the best solution is to lay an ethernet cable, this gives the best performance and zero latency. But, sometimes this isn't possible or cost effective. Lets look at the wifi alternative.

To extend internet to an outdoor shed the most obvious solution is to make use of an outdoor point to point WiFi link. This involves installing ethernet cabling from the main house router to the roof where a point to point WiFi bridge unit is installed.

On the outdoor building/office/shed the same has to happen, an outdoor WiFi bridge unit is installed on the roof with ethernet cable leading down in to the shed. At the end of the ethernet cable a single device can be connected or if needed a WiFi access point can be installed that will provide WiFi coverage to that area.

It is important to note that this type of connection requires line of sight and can work up to 5km.

Get in touch with a WiFi specialist for more information.

 

 

 

 

DKIM Validation – “Fail, message has been altered”

What is DKIM?

DKIM - or DomainKeys Identified Mail is an email authentication method. DKIM adds a digital signature to every outgoing message. This signature is examined by receiving mail servers to determine if the message was really sent from the sending domain.

Do I need DKIM?

DKIM help protect your domain from spoofing. DKIM also help to prevent your mail from being tagged as spam. DKIM is a MUST!

Implementing DKIM

It's always best to consult your email hosting company for documentation on how to implement DKIM properly.

DKIM is implemented by adding a TXT record to the domain's DNS zone file. Typically a DKIM entry consists of a "Host" entry and "TXT value"

DKIM Validation

It is very important to test DKIM once implemented. I use DKIM Validator

You can validate your DKIM by sending a test message to the randomly generated email address created on the DKIM validator website.

Once the test email has been sent, go to the DKIM validator website and click the "View Results" button.

Inspecting the "DKIM Information" section will show details about the encryption, public key, headers, public key DNS lookup and validation.

The important part to confirm if validation succeed is under the "Validating Signature" heading.

A successful entry should have " Result = Pass"

An unsuccessful entry could have "Result = Fail" "Details: Message has been altered"

DKIM Validation Fail - Message has been altered

If you get this error you can try the following:

  • Verify the DKIM entry is set up properly - check documentation for your specific host
  • Do a test from webmail, if validation succeeds then in points to the message being changed from email client in transit to the server
  • Get in touch with your hosting company technical support to verify DKIM has been implemented correctly
  • Check email server settings
  • Try a different email client - as weird as it seems I had this issue using Windows Mail, when I swapped over to Microsoft Outlook validation succeeded.

Windows Mail causing DKIM validation fail Message has been altered

A client approached me indicating that they have mail deliverability issues. Messages were not sent as DKIM has not been working. Upon sending a test to DKIM Validator I got "Result = Fail" "Details: Message has been altered"

The client was using Windows Mail for a mail application.

Even after checking, removing and re adding the DKIM record it made no difference. The hosting company tech support was not helpful as per them everything was set up and working the way it should on there end.

I tried setting up a new mail account on a different computer with Windows Mail but had the same issue "Result = Fail" "Details: Message has been altered". Sending test emails from webmail worked fine.

You guessed it, Windows Mail was the culprit, I installed Microsoft Outlook, added the account and Bingo, Validation result = PASS.

 

 

 

 

 

 

Brother printer keep disconnecting from wifi

I recently had a client call up saying their Brother printer keeps disconnecting from wifi. The client seemed to think it happens at random intervals and restarting the printer fixes the problem for a short period.

For starters I know that this printer uses 2.4GHz for wifi connection, and if the Brother printer continually disconnects it could be due to channel interference.

The first thing I checked was the wifi signal strength, 2.4GHz channel utilisation and latency to the Brother printer and other wifi devices on the 2.4GHz network.

I found that the channel wasn't being utilised by neighboring wifi access points but I did found that the latency to the Brother printer was erroneous and high. Usually this indicate channel interference so I decided to change the wifi channel in any case.

Unfortunately the wifi channel change did not make a difference to the erroneous pings to the Brother printer.

I then proceeded to update the Brother printer firmware, which again did not make a difference to the erroneous pings.

Either the erroneous latency to the Brother printer whilst connected to wifi is normal or  there is a component failure on the Brother printer, mind you another option is that the cpu on the printer is running at or close to its max.

Scouring through the internet it seems it was not unusual for users with Brother printers to have constant wifi disconnect issues.

How to fix Brother printer wont stay connected to wifi issues

The fix is rather unusual and seems to resolve the issue with Brother printers constantly disconnecting from wifi.

On the back of your Brother printer is a label with a password to access the web interface. Make note of this password and connect to the web interface via the IP address.

An easy way to find your printer IP address is to have a look at the settings > network > wifi > IP section

Once you have logged in to the Brother web interface, head over to Network > Wireless > IPv6 and check the enabled option.

The Brother printer should restart and hopefully stay connected to wifi.