Understanding Junk Mail Handling in GroupWise 6.5 - Part 2
Novell Cool Solutions: Feature
By Tay Kratzer
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Posted: 11 Nov 2004
Note: In order to fully understand this article, you must first read: ?Understanding Junk Mail Handling in GroupWise 6.5 - Part 1?.
As I've looked into the Junk Mail Handling feature I just keep uncovering more and more material. So we don't get to Troubleshooting or Administrative Control until the next part of this article.
Junk Mail Handling Behind the Scenes
Junk Mail Handling only applies to e-mail that has come in from the Internet. When an e-mail message from the Internet passes through the GWIA, it adds a hidden ?view? attribute to the message called ?Internet?. You cannot actually see this attribute when you view a message or it's properties, but you can see the ?Internet? view setting for your GWIA by doing the following.
- Edit the GWIA object in ConsoleOne
- From the SMTP/MIME view select the ?Message Properties? page.
- Notice the ?GroupWise View Name for Incoming Messages:? setting. It should read ?Internet? without the quotes, as shown in Figure 1. Case sensitivity is important. The ?I? in Internet must be uppercase. In writing this article I discovered that the GroupWise 6.5 for Linux GWIA makes the default name of the view ?internet?. This needs to be changed to ?Internet?, and for the Linux folks who know that case sensitivity to files is typically lowercase, don't worry in this scenario you should set the view to read ?Internet?.
GWIA Message Formatting
By using the ?Internet? mail view method to flag e-mail that has come in from the Internet, the POA doesn't have to activate the Junk Mail Handling engine code within the POA unless a message has the ?Internet? mail view. The advantage to this design is that the ?CPU expensive? Junk Mail Handling engine is only used when needed. What makes the Junk Mail Handling code even more ?CPU expensive? is when the black lists and white lists have lot's of entries. I'm telling you this not to discourage the use of Junk Mail Handling, but to lead you up to what I present in the next section called: ?Junk Mail Handling Thresholds?.
Here's the logic of the Junk Mail Handling engine so you can envision how it works:
Does the user have ?Junk Mail Handling? enabled?
NO -- Deliver message.
YES -- Proceed to Junk Mail Handling Engine
Junk Mail Handling Engine
- * The ?Junk List? or ?Block List? option must be enabled. Otherwise, continue with the next step.
- A sender address is examined in steps 2 and 3 before the domain is examined in step 4. This allows an entire domain to be ?junked? (i.e. hotmail.com) but a specific user to be trusted (email@example.com). Likewise, an entire domain can be trusted while specific users are ?junked' or ?blocked'.
Junk Mail Handling Thresholds
As I explained in Part 1 of this article, Junk Mail Handling was not designed to be a complex SPAM handling solution. Although, if you are willing to put up with the limitations of the white-list features of Junk Mail Handling, then Junk Mail Handling can potentially be a very effective SPAM solution.
There are limitations to the Junk, Block and Trust lists that you should be aware of. You cannot have more than 1,000 entries in a list. So you can have up to 1,000 entries in the Junk List, 1,000 Entries in the Block List, and 1,000 entries in the Trust List. There's another even lower limit too. Of the 1,000 entries in these lists, no more than 500 Internet domains can be represented in a list. Here are some examples to further explain these limits:
In my Junk List I have two entries:
The two ?@HOTMAIL.COM? entries only use up one of my 500 Internet domains that can be represented in the Junk List. The two entries use up two of the 1,000 entries that can be represented in the Junk List.
What happens if a user goes over the thresholds?
When a user adds an entry to one of their Junk Mail Handling lists, and the GroupWise client realizes that the list is too full according to the thresholds explained earlier, it prunes the list so that it can stay within the thresholds. The way it does this is it looks at the ?Last Used? values (shown in Figure 2) assigned to the entries in the list, and determines which address entry has not been used for the longest time amongst all of the entries in the list. The actual list ?pruning? process happens when a user exits the GroupWise client.
It's this ?pruning? process that caused me to write this article. One of my customers called and said that they had a user with around 600 entries in their Junk List, but the number of entries seemed to be changing without the user deleting entries. More particularly the user was aware that some of the addresses they had put in at one time were gone. So obviously this user had about 600 entries in their Junk List that represented 500 unique Internet domains. I couldn't understand why the user had so many entries, and the customer then explained to me that their SPAM filtering solution wasn't working too well. Ahhh?.. that's why!
So why the thresholds and the limits?
You've got to draw a line some place; and so GroupWise development did just this. As we explained earlier, the Junk Mail Handling engine becomes more and more CPU Expensive (with Internet messages) the longer the lists go. So they put in the thresholds mentioned. That said, there is one list for Junk Mail Handling that actually has no limits. It's the white-list feature of the Personal Address Books. There are no real limits on the number of entries in the Personal Address Book so the white list feature of the Personal Address Books has no limits.
Here's some more food for though. Because the Personal Address Books (including the Frequent Contact address book) for a particular user's account can be used as a white list, it's important to keep in mind that the Frequent Contacts list could be designed with ?Auto-saving on? of messages received and sent to the Internet, as shown in Figure 3.
So think about this. What if a user opens a message a message they would just as well have Junked? If Auto-Saving on for items received from the Internet is enabled, then effectively the mail has been added to the address book. Then the user enables Junk Mail Handling, and indicates that they only want messages that are in their Personal Address Books, because the Frequent Contacts address book contributes to the white lists, users may still get messages that they might not have realized they would have.
more Understanding Junk Mail Handling in GroupWise 6.5:
- Part 1: SPAM vs. Junk Mail
- Part 2: Junk Mail Handling Thresholds
- Part 3: Administrative Control of Junk Mail Handling
more Kratzer's Hot Docs
See other articles written by Tay Kratzer at "Kratzer's Hot Docs": http://www.novell.com/coolsolutions/gwmag/trenches/kratzer.html
|books to read|
Success with Clustering GroupWise:
A Guide to Building a Highly Available GroupWise System
by Tay Kratzer and Gregg A. Hinchman
Purchase info: www.taykratzer.com
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