About sending e-mail by AirMail and WinLink, via Internet to and from vessels at sea. If you come across unfamiliar words, check the WinLink glossary.

Most of the information on this page has been lifted from the WinLink homepage in August 2011. Since the original information may be changed or adjusted at any time, you are recommended to visit the WinLink homepage to make sure you have the latest version.


To send a message to a Winlink user (or, to allow the user to receive it) the sender's e-mail address must be listed in the recipient's whitelist (accept list). If the sender's address is not there the message will be rejected. This restriction can be bypassed by including a special keyword (//WL2K) in the subject line of each message. For example:

Subject: //WL2K (then any normal subject text)

The "//WL2K" informs the Winlink mail processing system to allow the message to be forwarded to the Winlink user. This code may be changed from time-to-time.

"Why are you doing this?"
SPAM control on the WL2K system is important because our licensed users and station operators are bound by laws and regulations that prohibit the content of most SPAM over radio. Moreover, slow radio circuits are easily clogged with unwanted messages when an urgent or emergency message must get through.

"I need a better explanation of why I'm not getting through..."
Your rejected message came from an e-mail account bearing a reply address that is missing from the "accept list" of your recipient WL2K user. Normally, if you have first received a message from a WL2K user, the address at which you receive your mail will have been automatically placed on their "accept list".

Sometimes however, your e-mail account may be set so that your reply address is different than the account address from which you send, or perhaps your internet mail provider is using an unusual method of mail header addressing. This can result in your message being rejected, because to our filter your mail appears to be coming from a different address or domain than the e-mail address where you receive messages. This is the way spam gets sent. Your mail set up makes your messages looks just like unwanted spam!

Thanks for your understanding.


About 90% of the messages into the CMS from the internet are Spam! In order to combat this problem it was decided by the Winlink Development Team than use of the Whitelist should be required of all users. The Whitelist is list of email addresses or domains that will be accepted when sending mail inbound to a WL2K user from the internet. Each WL2K user account has a Blacklist and a Whitelist. The entire Spam-Control mechanism is sometimes referred to as the "WL2K Whitelist".

ANY MESSAGE TO A WINLINK USER FROM THE INTERNET must be from a sender's address or domain name that is in the recipient's whitelist, OR AS AN OPTION, the sender must include the character sequence //WL2K in the subject line of the message. If //WL2K is found in the subject line, the message will be accepted and forwarded to all of the recipients of the message with amateur callsigns.

Subject://WL2K (then any other normal subject content to follow). If the sender is not in the recipient's whitelist and no //WL2K is found in the subject line the message will be rejected with a reference to the Winlink WEB page where instructions for sending WL2K messages will be found. Whitelist notices will no longer be created and forwarded to recipients.

There will be certain exceptions. Messages from future listed specific domains will be accepted unconditionally except where a recipient specifically blocks the domain name in their whitelist.

Also, starting August 1, the following Message precedence system will be in use. It should be used ONLY when absolutely necessary for emergency priority messages when large amounts of traffic are expected to a specific Amateur radio Winlink 2000 address.

For the subject of a message for a Winlink 2000 user:
  • Subject: //WL2K R/ (will be used for "Routine" Messages. This will be similar to the standard //WL2K above).

  • Subject: //WL2K P/ (Will indicate a "Priority" precedence).

  • Subject: //WL2K O/ (will hold a yet higher "Immediate" precedence). It should be saved for agency use.

  • Subject: //WL2K Z/ will increase the precedence to its highest "Flash" level. It should be saved for agency use.
The above options mimic the Military Precedence system for message handling, and has worked successfully for over a year on the MARS side of Winlink 2000 for their internal communications as well as for Federal, State and NGO Agency use. It certainly helps keep the gremlins away.

Obviously, educating those potential EmComm users of Winlink 2000 is mandatory as it should be regarding message size, etc.

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