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GroupWise: limiting message sizes


Left unchecked, some users will send the most ridiculously huge messages without any thought of the problems or even awareness of how big the file(s) is/are they are sending. It is an administrators job to keep such things from bringing down the system and GroupWise has a few good provisions to help limit huge messages from causing problems. The biggest two reasons for controlling message size are costs of bandwidth and storage. As there are a few points of control with different implications depending on which you have the greatest constraints, this is split into two main sections: Control Points and Recommended uses. Originally written for GroupWise 2012 but much will apply to earlier version as well as being extended to newer versions as I get to live them. Screen shots will get updated when they look functionally different, not just skin/UI updates.

Control Points

- GWIA
Your GroupWise systems' email connection to the rest of the world is one of the oldest points of control. While available Internet speeds have increased, it generally costs more to get that next level and email isn't the only thing using it. The other end of a sending your or receiving from your system also effects the flow. Many systems limit the size of messages that can be received and doing the same on your end can save a lot of headaches up front. One of the oddities of SMTP it does not originally include a size check up front (many but not all now do), but that the message has to be sent before its size is evaluated and rejected if too big.

In GroupWise Administration / ConsoleOne, got to the properties of the GWIA object, Access Control, select the Class of Service in question, edit the SMTP Incoming and SMTP Outgoing "Prevent Messages Larger Than:" as appropriate.

Start with the "Default Class of Service" and have any others you add either just inherit or have their own setting. Different class of services can be set for the special users (blocked from internet, or needs to send bigger messages than others to the internet) and they can be selected by user or Distribution group (set to be invisible if you don't want users to see those details). A common setup is to tightly limit their size at the "Default Class of Service", and have additional groups increasing the capabilities. Be cautious of blocking anything at this level as some disables at this level are very total. The "Prevent Messages Larger Than:" is based on the message in SMTP format, so MIME encoding bloat(approximately 1.37 times the raw file size) needs to be kept in mind.

Micro Focus' Documentation on this.
Note: GWIA's inbound limits should not be greater than any of the Agent links, otherwise senders may end up with a successful delivery notification when the message has actually been dropped. This is due to GWIA acknowledging delivery once it has received a message, but before the message has finished traversing to the user's mailbox.


- Agent Links
Direct Agent to Agent links which involve at least one end being an MTA. These are the ones for managing bandwidth use on WAN links and/or just setting hard maximums of size of messages flowing. There are no user level settings so a limit here applies to everyone's mail flowing between the agents, so tread carefully using this option. This can be used even if the entire system is in one location just to help manage storage use. In addition to the maximum message size, you can also set the delay message size which is the directs larger messages (up to the maximum above) to a lower priority queue so that they don't slow down the regular short messages.

For GroupWise 2012 and previous versions:
In ConsoleOne, right click on the Domain/PostOffice/GWIA, GroupWise Utilities, Link Configuration,

GroupWise 2012 Documentation on this.
Agent Link Config
Select the Domain connection, click on Edit Link icon (looks like a pencil) set you limits, OK, then click on the Save icon. Agent Link Details

For GroupWise 2014+:
In GroupWise Administration on the left side under Administration, select System. On the right select "Link Configuration".
Starting on the left, select a Source Domain, a direct linked Destination Domain (icon with a single line with only 2 points), then set the maximum message size for both directions.

GroupWise 2014R2 Docs, scroll down a page or so for this.
GW Agent Link Config

Note: When you are setting these settings, it is a good practice to enable a GWIA inbound limit at or below the lowest agent to agent limit, otherwise received over sized messages accepted by GWIA will be dropped by the agent to agent limits.

- User limits
The ultimate in user specific control that also includes quota options and notifications to the administrator when limits are being reached. These settings can be done at the for entire Domains, PostOffices, or for just a single user.

In ConsoleOne, right click on the domain, GroupWise Utilities, Client Options, Send, Disk Space Mgmt. Client Options size
When doing this at the PostOffice level you will get the following pop up that you should click 'Yes' to. PO Client Options set notice

Novell's Documentation on this.

- Mobility Service(GMS) limits
The default limit for GMS is 500KB, and that only relates to what the mobile device sees. The big implication is that it is also the limit of what can be effectively forwarded as if you forward a message with an attachment over the limit, the file gets replaced with a text file originalfilename.ext-.TXT saying that the size limit has been exceeded.
So if you want your users to be able to forward those larger messages at all from their mobile devices, you'll need to up that limit quite a bit. Don't worry too much about the device connection charges because those attachments are only uploaded on demand, and if you have troublesome users that way, then you may just have to reduce what that user is allowed in other ways.
I do think that GMS does need a per user and/or per group control for this to manage those trouble users and if you agree, please submit vote for Enhancement Idea. Another Idea looking for votes is for some other avenue for attachments larger than the limit.

Micro Focus' Documentation on this.

Note that 1 MB equals 1024 KB, or 1 TB equals 1024 MB or 1048576 KB. The difference is computers think in Base2 (binary), vs most of us wetware think in Base10 (decimal).


Observations/Recommendations

Start with the Domain level User Send limits and GWIA level limits as they both allow for exceptions.
Be careful of with the Agent-Agent link limits as those are hard limits for all traffic flowing through the link and need to be more than twice that of the max inbound GWIA level limits. Use the Agent-Agent link limits as your maximum allowable if at all, but certainly make use of the "Delay message size". This 'delay' just sets the larger messages to a lower priority queue, so the messages will still flow but lets the 'little ones' flow more regularly. This lower priority queue keeps the lumbering giant messages flowing just one at a time vs the normal multi-lane flow.


How to tell what blocked the message

As a general rule, the longer it takes for the system to notify you of a limit problem, the further away that limit is.

- If you get a pop-up stopping you, it is your User limit you are hitting.

- If you get a message like below, it is the Agent-Agent limit and it tells you which agent is involved.

  Message cannot be delivered because administrator has enforced message transfer size limitation.
  Sender: your name
  Subject: what ever the subject of your message was
  Item Type: MAIL
  Message ID: 52B500CC.A1B:17:47632
  Post Office Name: Main.Domain
  Transfer Limit is 20000 KB
  Message size 30113 KB exceeds Transfer Limit of the agent
 In this case you can see it is a Post Office to MTA link, so look at Link Configuration from the Post Office in question and the Link to its owning Domain.

- If you get a message like below, if was the GWIA level limits

  Subject: Item to Domain.GWIA was undeliverable, subject: what ever the subject of your message was
  Message exceeds maximum allowed size
Check your which 'Class of Service' you belong to, including checking any you might be a member of.

- If you get a message like below, if was somewhere beyond GWIA. Either the destination system or any filter systems in between.

  From: Domain.GWIA.GATEWAY
  Subject: Message Status - Undeliverable
  .......
  Transcript of session follows: 
    Command:  MAIL FROM:
    Response: 552 5.3.4 Message size exceeds fixed limit
Note that the exact 'Response: 5xx' message details will vary from system to system as that is direct from the system rejecting the over-sized message.



Last updated 2017-01-12 Copyright © 2017 Andy Konecny andyweb @ konecnyconsulting.ca