At present, there are four main mailing lists for ARM Linux, listed below. For subscription, unsubscription and other user administration activities, please see the list information page for more information.

Please note: Russell gets lots of email. If you wish to ask a question about ARM Linux, please ask it on these mailing lists rather than directing it to Russell's email addresses. You'll stand a better chance of getting a reply. Thanks.

Legal notice: The linux-arm, linux-arm-kernel, linux-arm-toolchain and linux-arm-announce mailing lists are located in the EU. By posting messages to any of these three lists, you implicitly agree that the posted messages are in the public domain, and as such may be freely copied, archived, duplicated, and sent to other persons both within and outside the EU. If you are unable to agree to this, DO NOT post messages to these lists. In order to post messages to these lists, you must be subscribed. Posting messages from an email address which isn't subscribed will be deemed as a rejection of this statement. Posting messages from an email address which is subscribed is deemed as an acceptance of these terms.

The linux-arm and linux-arm-kernel mailing lists have a top 10 poster ranking.

Notes:

1. Note 1 - SPAM (or unsolicited commericial email)
   We operate an anti-spam policy on the mailing lists. Although we attempt to prevent as much spam getting to the mailing lists as possible using various techniques, we aren't always successful.

   However, the list server is set up to detect messages received from a possible spam source ("open email relay" or just "open relay"), and will mark messages believed to be from such an "open relay" with a X-RBL-Warning header. These headers contain information describing why the system believes you are a source of spam.

   The list server ignores this header and will pass the message to subscribed individuals. However, the action taken by these individuals upon receiving such a message is a decision that they are free to make.

   Please note, however, that if the system relaying your email to these lists is classified as an "open email relay", we are unable to resolve this; please do not contact us. It is a matter between you and your Internet Service Provider to resolve with the appropriate RBL system. Please see mail-abuse.org and/or www.spews.org for more information on the subject of RBL.

2. Note 2 - Sender Verification
   Email to these mailing list(s) (and @arm.linux.org.uk addresses) has the "envelope from address" (the email address which appears in the SMTP MAIL FROM: command) checked for validity. Invalid envelope from addresses are rejected. A typical rejection message includes one of the following phrases:

   451 Sender verify callout did not complete

   550 Sender verify failed

   In the latter case, you should see some additional 550 lines describing the exact nature of the failure, eg:

   550-Verification failed for <xxx@yyy.zzz>
   550-Called:   xxx.xxx.xxx.xxx
   550-Sent:     RCPT TO:<xxx@yyy.zzz>
   550-Response: 550 unknown user
   550 Sender verify failed

   The envelope from address is used to send error messages to the sender of the message (see RFC2821 section 3.3). Unfortunately, because the envelope address is invalid, error messages are unable to reach you, so you will never know whether your message failed to reach any recipient you mail.

   In addition, some sites block the SMTP MAIL FROM:<> syntax, believing it to be a spam source. This is unacceptable since the special MAIL FROM:<> is used to send error messages back to the message originator, as described by RFC2821 section 3.7 with additional discussion in 4.5.5. As a result, messages originating from such systems will also be rejected.

   Please note that some ISPs mail servers incorrectly respond with a 5xx permanent error code when they are processing a lot of email, rather than a 4xx temporary error code. This can cause the verification to fail unexpectedly, and your message will be rejected. This is due to non-RFC2821 compliant email software, and is a problem for that only your ISP can resolve.

3. Note 3 - Explicit Congestion Notification
   This list server uses Explicit Congestion Notification (ECN) (RFC3168), which is a TCP extension to reduce congestion in the Internet backbone infrastructure, and provide a better overall service to the Internet as a whole. However, there are two caveats:
   1. Some routers had buggy firmware which refuses packets with ECN; vendors have released updates for these routers. Please see the ECN-under-Linux Unofficial Vendor Support Page for more information.

   2. Some firewalls have been setup which deny packets using the ECN protocol (which date from the pre-ECN time.)

   Any of the above listed reasons can cause the envelope verification (see note 2) to fail, normally with the 451 code, thereby rejecting your email.

4. Note 4 - SMTP EHLO/HELO names
   The SMTP commands EHLO and HELO are followed by the mail "domain" name of the host connecting to the mail server. This domain name must be acceptable according to the rules given in RFC2821 section 2.3.5. Hosts using invalid domain names will have their connection terminated, and therefore will be unable to send email to this list.

   Unfortunately, Microsoft(R) Windows(R) traditionally allows the machine name to contain an underscore (_) which, when used, violates the SMTP specification. Please ensure that any Microsoft(R) Windows(R) machines are configured correctly according to the accepted Internet Standards published by the Internet Engineering Task Force if they are going to be part of the Internet.

5. Note 5 - New threads as Replies
   There have been lots of people on these mailing lists using the "Reply" button in their mail client to start a new message thread. This is bad because it breaks message threading in the archives and mail readers, leading to new threads being lost amonst unrelated older threads.

   In order to prevent this happening, these mailing lists have filters which detect such behaviour, and hold such messages for review. If it is found that the message is starting a new thread, it will be rejected; please do not using the "Reply" button lazily.

   Conversely, there are various mail readers which do not include the necessary message headers for message threading to work, and these posts will also be held.