Try not to mask out detail from your log extracts, configuration snippets, error messages, or problem statements. There are often important clues to be found there, and what's irrelevant detail to you could be the key to the problem (this makes sense because if you knew what was important already, you probably could have solved the problem yourself).

At a minimum, leave the RHS of email addresses intact, and all IP addresses. There's nothing secret about an IP address, and nobody can deduce anything from a domain name in your log that they can't find in dozens of other places already. If individual localparts are key to the problem, try to leave those intact, too. If you must avoid posting a particular localpart, try to recreate the problem on your server using a dummy address.

Apart from these reasons, it's only too easy to introduce errors when you manually obfuscate things prior to posting, and the people answering your question will waste time pointing out inconsistencies in your obfuscation rather than concentrating on the real problem.

This rule is part of the agreed MailingListEtiquette followed on all Exim mailing lists.

You may find that some people on the Exim mailing lists refuse to answer questions posted with obfuscated logs or configuration files. If you post obfuscated details on the mailing list, you may receive a reply directing you to this page. If you repost your question with unobfuscated logs and configuration files, you might be more likely to receive a helpful answer from the members of the Exim mailing lists.