Hello everyone,
While building a custom mail system, i've came across the following bug at Icloud mail and i'd like to share it with the community.
A message that has the first part of its Message-ID header composed only of digits (0-9) and letters from (a-f,A-F), in other words the hex alphabet, is lost even if the SMTP delivery is successful on sender's side.
To validate the issue, several SMTP services were used and the results were identical.
You can try it by using the following message-id headers:
Message-ID: <123acb@example.com> (Mail lost)
Message-ID: <123xyz@example.com> (Mail received)
While building a custom mail system, i've came across the following bug at Icloud mail and i'd like to share it with the community.
A message that has the first part of its Message-ID header composed only of digits (0-9) and letters from (a-f,A-F), in other words the hex alphabet, is lost even if the SMTP delivery is successful on sender's side.
To validate the issue, several SMTP services were used and the results were identical.
You can try it by using the following message-id headers:
Message-ID: <123acb@example.com> (Mail lost)
Message-ID: <123xyz@example.com> (Mail received)
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