[HOWTO] DNS Flush in OS X Tiger and Leopard

OS X Tiger uses

lookupd -flushcache

to flush DNS entries.

OS X Leopard uses

dscacheutil -flushcache

to flush DNS entries.

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How Email and Digital Signing Works

Digital signing is used to confirm authenticity of the e-mail sender and encryption is used to secure the communication to prevent others from seeing the content.

For example, John and Jane works on a top secret project and wants to make sure that their e-mail correspondence is secure. Each of them has a personal certificate and send a digitally signed non-sensitive e-mail to each other. When John receives Jane’s email, his computer check the authenticity of Jane’s certificate through the Certificate Authority (CA). Read the rest of this entry »

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