Generate emaill address using another column

 =IF(C2="",CONCATENATE(B2,"@","domain.com"),C2)

How to write or append a file without opening in Linux?

 echo "hello world" >> /directory_path/my_file.txt

Steps to configure after PowerMTA Installation

 Steps:

1. Setup PMTA

2. Install Open SSL & Make Certchain with key & cert

3. Create Selector,Generate DKIM public & Private keys 

4. Create CNAME with selector and point to TXT record having public key values

5. Create .pem file in specified directory and add corresponding DKIM private key(s)

6. Setup Master and Subordinate SPF

7. Set PTR & corresponding hostname for IPs

8. Set DMARC, BIMI , MTA STS record

9. Create & setup Domain config file

10. Create & setup PMTA config file 

11. Start PMTA, Test Deliverability

Fix the Windows and Outlook “Indexing Is Paused” Error

Method-1: Registry Tweak

1. 

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\

or

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search

2. Press “Windows Search” on the left, then double-click “PreventIndexingOutlook” on the right.

3. If you don’t have “Windows Search,” you can create it by right-clicking “Windows -> Edit -> New -> Key.” Name it accordingly, then create the “PreventIndexingOutlook” value by right-clicking an empty space on the menu on the right and selecting “New -> DWORD Value (32- bit).”

4. Once created, double-click it to adjust the “Base” to “Hexadecimal” and change “Value data” to “1,” then click “OK.”

5. Reboot Computer

Dovecot: Disconnected, connection closed, auth failed

 From webmin dashboard>Servers>Postfix Mail Server> Virtual Domains> Find specific user maping 

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How to append one file from multipe file in Linux

cat file1 file2 > file3