Typical Return Mails

SkyFile Mail and SkyFile-C are satellite-based e-mail services. Please understand that we are obliged to protect customers from high transfer costs and thus handle e-mails to their accounts more restrictively than typical terrestrial Internet providers. If an e-mail from you has been rejected, you will find possible reasons here.

Return mails after sending messages to SkyFile Mail users

Please read all return mails carefully. They come either from MAILER-DAEMON or POSTMASTER and always contain valuable information. Look for one of the following phrases, and do not simply resend your e-mail without having read the following. Your local mail server might add its own, sometimes even misleading interpretation, but only this is relevant:

• Delivered mail(s) to ...: No error! Your message has been retrieved by the SkyFile user. You will get this message only if confirmations are enabled for this user and a SkyFile user - either the same or another - has sent you an e-mail within the last few days.
• Access denied: The account requires a special keyword in the subject line, or e-mails are accepted from predefined addresses only. Please contact the owner or his company. Different reasons are possible (BWL means black&white list):
  - Access denied: not registered (mail to an Inmarsat-C address without being registered user)
  - Access denied: keyword (subject keyword missing or not correct)
  - Access denied: B&W Prepaid (not allowed due to personal prepaid BWL)
  - Access denied: B&W (not allowed due to postpaid BWL)
• Account renamed, use ...: The account name before the @ character in the address has been renamed. Please replace the old name by the new one, the subaccount before it (if any) and the domain name remain unchanged.
• Blocked by spam filter: Some of the e-mail characteristics indicate spam. Send your e-mails as plain text instead of HTML or Rich text and use personal addressing (TO, CC) instead of blind copies (BCC).
• Content is blocked: Mail header lines are typical for spam e-mails, e.g. faked mail server names in a Received line, or suspicious words in the subject.
• Faked sender: If you are using an address at a large provider like AOL, GMX, Hotmail, Web.de or Yahoo, please make sure that you send your e-mail via the mail server of this provider.
• Invalid address: The destination address is syntactically wrong, e.g. illegal characters before @. Valid SkyFile usernames only contain alphanumerical characters, dashes, underscores and no or one dot.
• Invalid Helo: Your mail server must identify itself with its own fully qualified Internet domain name, including the top-level domain. Please ask the server administrator to correct the setting.
• Invalid sender: Your own mail address (appearing as "From" in your e-mails) is syntactically incorrect, e.g. invalid characters or missing domain name, which would make it impossible to answer.
• IP blacklisted in zen.spamhaus.org: Viruses or spam mails were sent from your server. After delisting its IP at the Spamhaus web page, the blocking may continue for 36 hours due to DNS caching.
• IP is blocked: We do not accept mails from dial-up hosts and dynamic IP addresses because these are typical for spam and viruses. Please send your mails via the SMTP smarthost of your provider.
• IP temporarily blocked: Your address is blocked for a while after too many errors, e.g. lots of mails to non-existing addresses. This may be the result of viruses or backscatter from your server.
• Mail expired - Your mail was not read within...: Your mail was deleted after a service-dependent number of days. Please inform Marlink if the account is no longer needed!
• Mail to ... not retrieved within 24 hours: You will get this information if delivery notifications are enabled for the addressed SkyFile user and the mail was not retrieved within 24 hours. Please do not resend your e-mail since it is still available for retrieval.
• Mail too long: Try to omit large attachments, and do not send HTML e-mails. The allowed max. size depends on the recipient.
• Separate filters for subaccounts not supported: You must send a black&white list to the root account, not to one or more subaccounts.
• Sender blocked: Your sender address is invalid or was blacklisted, e.g. after unrequested newsletters, bulk mails or other sorts of frequent e-mail abuse.
• The attachment... has been deleted: The text was sent completely but an attachment file was superfluous, too large, or unwanted (e.g. Winmail.dat with Outlook-specific rich-text formatting; always use "plain text" as mail format).
• Try again later: If you ever see this message, your mail server does not handle greylisting correctly. Please ask the manufacturer for an update which does not interpret the SMTP code 451 as a final error and which sends return mails for final errors only.
• User does not exist: The user name (which is the part of the mail address before the "@" symbol) does not exist at the SkyFile Gateway in the LES. Please check your address list.
• User inactive: There was no satellite contact with this SkyFile user for at least three months, or the billing limit of the addressed postpaid subaccount has been reached. The user must dial the gateway at least once and/or change the limit.
• User mailbox full: The mailbox capacity for this user is exhausted. Please wait until the user has retrieved all his mails before sending your message again.
• Other return mails from a Mailer-Daemon or Postmaster other than the one at the LES are created if the domain name (the part of the address behind the "@" symbol) was wrong.

What is Winmail.dat?

Winmail.dat is an attachment container encoded in the "Transport Neutral Encapsulation Format" (TNEF), a proprietary format sometimes used by Microsoft Outlook and Microsoft Exchange. It contains rich-text formatting (RTF) as well as the original attachment(s). Since it does not comply with Internet standards (RFC documents), other email programs often cannot decode it. Typically the usage of Winmail.dat is caused by a misconfiguration in Outlook and/or Exchange since it is not intended for external emails. A Microsoft web page explains how to correct this configuration.

Additional return mails after messages to SkyFile-C users

• Attachments not supported: You cannot send file attachments to Inmarsat-C users because their transceiver software is unable to decode and display any attachments. Sometimes short attachments can be sent to a special address; please contact the owner.
• HTML mails are blocked or No HTML-formatted mails possible to Inmarsat-C: Your mail must have a plain-text body. Inmarsat-C transceivers cannot display or print HTML-formatted e-mails. Though the SkyFile server could convert them to plain text, this often would have unwanted side effects.
• Temporarily unreachable, message stored in mailbox: The Inmarsat-C transceiver has been switched off or logged out. Your mail will be retried later, so please do not send it again.
• Too long, limit is xxx: The length of all e-mails to this user is limited to a maximum of xxx characters due to the volume-based cost of Inmarsat-C satellite transmissions.
• Message to... of...: Delivery status of your mail, with these alternatives:
  Ref. ...: Your message was sent to the Inmarsat-C transceiver. (You will get this message only if confirmations are activated for this Inmarsat user, and if the same or another satellite user has sent you an e-mail within the last few days.)
  Barred: The mobile transceiver is barred e.g. due to open Inmarsat invoices or other problems.
  Dest disconn, dest timeout, no conn possible: There were technical problems sending the message.
  Logged out: The mobile transceiver is currently switched off, sending messages to it is currently not possible.
  Unknown: The mobile transceiver is not yet or no longer registered at Inmarsat.

Return mails after changing the black&white list

• Black&white not enabled, contact customer care: Sending a mail with .setfilter in the subject is reserved to control the e-mail filter, also called black&white list. Avoid this word in other mails.
• List updated, List deleted: The mail filter (black&white list) has been updated as requested. The list is deleted if there are no lines starting with + or - in the request mail sent earlier.
• Too many invalid lines: You have tried to update the black&white list, but there were too many lines not starting with + or -, so it is not clear what the real intention was. Check the format.

Anti-virus and anti-spam policy

• If an e-mail to a SkyFile user is clearly a virus, it is deleted without sending a return mail. Viruses are detected using a heuristic algorithm even in ZIP files.
• Due to the high risk of new virus types, executable files are blocked. If the length is typical for known viruses, they are also blocked in ZIP files even if these are password-protected. This happens for files with the exensions EXE, COM, CMD, PIF, SCR, BAT, LNK)
• If an e-mail is apparently spam, it is blocked, but a return mail is created in order to inform the sender if the spam score is in a critical range.
• If an e-mail comes with plain text plus an HTML alternative, the HTML alternative part is deleted without notice, only the plain text is passed through.
• If you apparently get spam or viruses from SkyFile users, please be aware that the sender's address is probably faked. The true sender IP can be found in the mail header.
• Of course no guarantee can be given that all existing and future types of viruses, worms and Trojans are detected. We advise all SkyFile users not to open any unexpected attachments.

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