I did a Wireshark capture of my login into a drupal-based website. The website does not use https. And so, quite obviously, I was able to capture my username and password in plain text by simply  using the http.request.method==POST filter in Wireshark. 

Then, I tried to access the same web page by manually adding a s to http in the url. Quite naturally, my browser showed this:



Then I went ahead and did my login again, and did the Wireshark capture again. 

To my surprise, I do not have the any captures corresponding to the http.request.method==POST filter. 

So, my questions:


When I am not really using https, why wasn't I able to capture login id and password in plain text?
What effect did manually adding s to http have?



Question: How does postgrey handle changing FQDNs?
Answer: The reason Postgrey sees them as different clients is simply because they are. Each is a Different server with a unique ip-address and hostname. 

Unless you add them to a whitelist first  they each have to prove they behave like a proper smtp daemon. 

But if they all are trusted clients you do not have to individually add them to the whitelist, you have the following options:

# Whitelist the whole domain
example.com
mail.net

# Use Regular Expressions 
/^mail[0-9].dx[0-9]{3}.mail.net$/

# Use CIDR IP Addresses:
10.9.8.0/24