Pretty graphics and shiny buttons do a good job of telling me the quick and dirty info on an e-mail message, like who it’s from, but I’m a meat and potatoes/text and IP addresses kind of guy, so I was happy to find out that you can easily check the source information on an e-mail message in Mozilla Thunderbird with a few simple clicks.
First, click on the e-mail in question, so it shows up in your preview window (usually located on the bottom).
Now, highlight all the test in the message…
…and go to View>Message Source in the top toolbar. (you can also hit Ctrl+U, if you like keystrokes better)
Poof! Up comes a text file with all the numbers! Now you can geek out ’till your heart’s desire!