3 ways to provide better Exchange service to low-bandwidth sites

Almost every large organization has at least a handful of users who work at a remote site, and sometimes that site is so remote that the only Internet access is via satellite or dial-up. You might be tempted to install an Exchange server on location, but consider the ramifications:

  • You can’t configure DAG replication to your main data center because the pipeline is too small.
  • If you want HA capability for the affected users, you’ll have to install at least two Exchange servers.
  • You will have to maintain these servers across a satellite or dial-up WAN connection.
  • You probably don’t have onsite IT support to maintain the hardware.
  • All email for all users will still have to cross that slow link in both directions.
  • Software licenses and hardware can be expensive.

When all factors are considered, an Exchange server at a low-bandwidth site to service a small number of users is a bad business and technical solution. In fact, it will probably just cause more problems than it solves.

All hope isn’t lost, however. Here are three things you can do to make a bad situation at least bearable.

  1. Configure all Outlook clients at the remote site to use cached mode. For new users, this will work great. Their mailboxes will start empty, so there isn’t a lot of data to move initially. For other users, depending on the bandwidth, the initial load time could be unworkable. Transferring gigabytes of data over a dial-up connection isn’t an option.

    Cached Exchange Mode

    Cached Exchange Mode

  2. Limit message size for the remote users. If you allow 50 MB messages by default, you could restrict users at the remote site to 10 MB or even 5 MB. In today’s email world, that might sound like a very tight limit, but if you’ve ever spent thirty minutes waiting for a large email to download across a dial-up connection, you understand that you would be doing these users a favor.

    Message size restrictions

    Message size restrictions

  3. Disable MAPI, POP3, and IMAP4 for the remote users. To a traditionalist, this might seem like a drastic move, but requiring desktop users to access email via the Outlook Web App is probably the one thing that will give your low-bandwidth users the best performance. Exchange ActiveSync allows them to receive email on their mobile devices, while OWA gives them full-featured access to their mailboxes through a web browser. In both cases their bandwidth usage will be a fraction of what the full Outlook client would require. Unfortunately, you can’t disable EWS, so Mac users will probably still be able to use Outlook.

    Disable all connection methods except Outlook Web App and Exchange Activesync.

    Disable all connection methods except Outlook Web App and Exchange Activesync.

Nothing is ideal about a low bandwidth site, but sometimes we have to make the best of what we have. Rather than spend a lot of money on hardware and a lot of time trying to remote into a server on the other side of a straw, consider changing the way that your users interact with their mailboxes. It will take some time to adjust, but they will probably be grateful in the end.

Update: Outlook 2013 supports Exchange ActiveSync (EAS), but unfortunately and bizarrely, it does not support using EAS to connect to an Exchange server. Otherwise, I’d say that EAS via Outlook 2013 would be a great solution in this scenario.

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