SailMail via Iridium GO! exec

The Iridium “GO! exec” is Iridium’s Certus-100 terminal, a completely different device than the Iridium “GO!”. The original GO! is quite slow (2400 baud), but has an available unlimited data plan which makes it quite attractive from a cost point of view. Access to the original GO! is also restricted to approved apps (including Sailmail), and Airmail includes a special “Iridium GO” device selection to support connections to Sailmail.

The GO! exec is considerably faster (88K baud) but usage is all charged per MB– there are no unlimited* plans (see below). So it is necessary to manage the data connections, otherwise browsers, windows updates, etc will all have a wild party with your credit-card. This is done by setting up a firewall “profile” in the GO! exec for Sailmail (or other services that you want to use), limiting access only to those servers.

For Sailmail, don’t try to use the “Iridium GO” connection, the GO! exec won’t understand the commands. Instead, connect the computer to the GO! exec as a normal WiFi device, but first create a custom firewall “profile” in the GO! exec setup and select that before connecting. Do that as follows:

  • Profile name: Sailmail
  • Description: Sailmail access (or whatever you like)
  • DNS blocking: enable (don’t allow DNS — see note below)
  • Rule policy: Block All Except:
  • Profile rules:
    • IP address:, single port: 50, TCP (this is our “server 1”)
    • IP address:, single port: 50, TCP (“server 2”)
    • IP address:, single port: 50, TCP (“backup 1”)

(This is covered on pg. 84 of our copy of the GO! Exec user manual, June ’23 revision).

To connect, first connect select the Sailmail profile and connect the GO! Exec to the internet. The profile rules will limit access to only Sailmail servers, so no other data will be used. (Verify this by checking the data usage on the GO! Exec). Then open Airmail’s internet window (yellow lightning-bolt button), verify NO check-mark for “First Connect to”, and click the green “Connect” button (or the “Check All” button). Airmail will connect to the server, check for messages, and disconnect.

* NOTE: Some services (notably PredictWind) offer an “Unlimited* Data Plan”. Read the fine print carefully, a paid weather subscription is required and data is limited to PredictWind data only, not from other services. Pre-paid “AnyApp” data is available in 10/20/30 MB buckets for $3-4 per MB, about the same price as the normal plans (GO! exec 5, 25,100,250) which provide complete flexibility.