How to improve DNS lookups on Linux system
Listing multiple DNS servers in /etc/resolve.conf defines primary and secondary DNS servers. If the primary fails, the system switches to the secondary after a timeout.
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Assigning retention policies to email folders
Zimbra users can configure the removal of email that has stayed in their mailbox too long, similar to removing mail from Trash (normally after more than 30 days). This feature is convenient for users who receive mail and want…
Steps to install Ruby Version Manager (RVM) on CentOS 6
CentOS 6 ships with Ruby 1.8.7. Ruby Version Manager (RVM) lets applications use other Ruby versions without changing the main system.
How to fix "unary operator expected error" in bash script
If testing a shell script produces [: =: unary operator expected error, check the if condition on the reported line to see whether the variable has a value and whether the code…
How to create a partition size larger than 2 TB on linux
Disks larger than 2 TB require a GPT-capable partitioning tool. gdisk works much like fdisk and supports large disks and up to 128 partitions.
Backup incoming mail from zimbra system to another mail system
Edit /opt/zimbra/postfix/conf/mail.cf and add the following two lines. sender_bcc_maps = pcre:/opt/zimbra/postfix/conf/archive_mail recipient_bcc_maps = pcre:/opt/zimbra/postfix/conf/archive_mail
How to transfer the anti-spam database to another Zimbra server
When migrating zimbra to a new system or installing a new zimbra server, you can retain spam detection as effective as the previous system.
How to install whois using yum on CentOS
whois queries domain information directly, helping administrators check domain ownership, expiry dates, or use the information in scripts.
Improving Anti-spam on Zimbra with Whitelist/Blacklist
Email sent by users often ends up in the SPAM folder of recipients on the same Domain or system because the anti-spam system considers the message to resemble SPAM.