How to view email headers in any email program

Do you have a spam problem and you need help to understand why you got it or what happened? Do you have a message failure or bounce error? The tecnician helping you with this problem will probably ask for this information.


  • Select the spam message
  • Click the down arrow next to to the reply arrow
  • Select "View message source."

Apple Mail

  • Select the spam message
  • Click View > Message > All Headers


  • Double-click to select the spam message and open it in a new window.
  • Click File > Info > Properties.
  • The header is displayed under "Internet Headers."


  • Select the spam message.
  • Click View > Headers > All.


  • Select the spam message.
  • Click "Full Headers" below the email.


  • Select the spam message.
  • Click the down arrow next to the reply arrow.
  • Select "Show Original."


Choosing a default email application

How to tell your Mac which program you want to use to send an Email.

Open Mail (/Applications/Mail).


Do this even if you don’t want to use Mail! Yes, it’s counterintuitive, but, work with me here.

From the Mail menu, choose Preferences.


Click the General button.


Choose your desired default email application from the "Default email reader" pop-up menu.


Top 5 Effective E-mail “Do’s

Top 5 Dos

5. Put important information in bold, so it’s easier to see. Likewise, if you’ve addressed an e-mail to several people and there’s an action for a certain person, bold his or her name when you address the issue. Use bold sparingly, though.

4. If action is required, say so at the start of the e-mail. Don’t tell a long story with the requested action at the bottom. This is called the BLUF method, but I also tend to call it “getting to the verb.”

3. Keep your signature short and professional. Lose the pithy quote and just include your title and phone number.

2. Keep the subject line relevant. If the topic changes over the course of a long thread, update the subject so it’s relevant.

1. Proof your e-mail before you send it. And make sure your spell checker is running.

via Top 5 Best Practices for Writing Effective E-mail | Business Hacks | BNET.

Top 5 Effective E-mail “Dont’s

Top 5 Don’ts

5. Don’t ever type anything in ALL CAPS, even to get someone’s attention. If you need to catch someone’s eye with something important, put it in bold.

4. Don’t include your entire team or your boss on every e-mail you send. Be selective.

3. Don’t send large attachments unless absolutely necessary, especially to a mailing list or distribution list. If possible, upload your files to the cloud, such as DropBox or MemoPal and provide a link.

2. Don’t send e-mail when you’re emotional. If you’re responding to someone that has made you angry, save the message in your drafts folder until you can proof-read it more objectively, and then send the e-mail.

1. Don’t try to be funny, especially to a mixed audience. The chances of being misunderstood are astronomical.

via Top 5 Best Practices for Writing Effective E-mail | Business Hacks | BNET. – About reindexing messages

If there are problems with information in your mailboxes, it may be necessary to reindex your messages. During this process, certain Mail folders on your computer are moved to another location, such as your desktop. When Mail is reopened, it rereads and reindexes all messages in all local mailboxes. The reindexing process can take several minutes depending on how many messages are in your local mailboxes.

When Mail detects a problem with your mailboxes, it may alert you that it needs to repair them by reindexing your messages. At other times, you can reindex messages yourself. To do so, quit Mail and, in the Mail folder in your home Library folder, move the Envelope Index file and any folders that begin with “Mac-“, “Exchange-“, or “IMAP-” to a different location, such as your desktop. When you reopen Mail, it reindexes all messages. – Rebuilding mailboxes

In some cases, you might need to rebuild a mailbox to update the list of messages in the mailbox–for example, if messages appear to be missing or garbled, or if you can’t find all relevant messages by searching. Rebuilding a mailbox can take awhile; it’s recommended for fast Internet connections only.

To rebuild a selected mailbox:

Choose Mailbox > Rebuild.

For IMAP accounts, locally cached messages and attachments are discarded and the messages and attachments are downloaded again from the server to your computer. Your mailbox appears empty until the download is complete.

Understanding Encryption

Cyber Security Tip ST04-019
Understanding Encryption

Encrypting data is a good way to protect sensitive information. It ensures that the data can only be read by the person who is authorized to have access to it.

What is encryption? In very basic terms, encryption is a way to send a message in code. The only person who can decode the message is the person with the correct key; to anyone else, the message looks like a random series of letters, numbers, and characters.

Encryption is especially important if you are trying to send sensitive information that other people should not be able to access. Because email messages are sent over the internet and might be intercepted by an attacker, it is important to add an additional layer of security to sensitive information.

How is it different from digital signatures? Like digital signatures, public-key encryption utilizes software such as PGP, converts information with mathematical algorithms, and relies on public and private keys, but there are differences:
• The purpose of encryption is confidentiality—concealing the content of the message by translating it into a code. The purpose of digital signatures is integrity and authenticity—verifying the sender of a message and indicating that the content has not been changed. Although encryption and digital signatures can be used independently, you can also sign an encrypted message.
• When you sign a message, you use your private key, and anybody who has your public key can verify that the signature is valid (see Understanding Digital Signatures for more information). When you encrypt a message, you use the public key for the person you’re sending it to, and his or her private key is used to decrypt the message. Because people should keep their private keys confidential and should protect them with passwords, the intended recipient should be the only one who is able to view the information.
How does encryption work?
• Obtain the public key for the person you want to be able to read the information. If you get the key from a public key ring, contact the person directly to confirm that the series of letters and numbers associated with the key is the correct fingerprint.
• Encrypt the email message using their public key. Most email clients have a feature to easily perform this task.
• When the person receives the message, he or she will be able to decrypt it.

Authors: Mindi McDowell Copyright 2004 Carnegie Mellon University. Terms of use