My thread notification e-mails are going to the wrong address?

No wonder I haven't been getting notifications

[pinterface]

Suppose for a moment my e-mail address here is set to <[e-mail]>; rather than sending mail to this address, webmasterworld is sending mail to <[e-mail]>.

Which, while handled by the same mailserver, is another e-mail address entirely. I can think of two possibilities for this:

1. WW is swapping out the given hostname with rDNS(ip(nuts.example.com)), in this case berries.example.com. This seems rather unlikely, due to breaking for just about everybody.
   
2. WW is rewriting the e-mail address to canonicalize hosts (nuts.example.com is a CNAME for berries.example.com, because it was easier than duplicating half a dozen DNS records). This seems the likely culprit.
   

One of us is wrong. Either there's some corner of an RFC I missed which says rewriting host names is okay and I need to change my DNS config away from being a CNAME, or WW is doing a Very Bad Thing. Both scenarios are plausible--WW is the only place I've encountered with this particular behavior; however, very few places fully implement RFCs (how many websites can handle the full range of e-mail localparts, after all?).

So enlighten me!

• Have I assessed the situation correctly?
  
• If this behavior is allowed, by which RFC and what section?
  
• If not, why is WW doing it?
  
• (Not really related, but while I'm here...)-webmasterworld.com (dash) rather than s74498.webmasterworld.com (dot)?
  

[Brett_Tabke]

We don't do anything with the name other than dump it to send mail if it looks like a legit email address. If it doesn't look like a legit email - we don't use it.

[jatar_k]

I did a mail test on your address

Getting MX record for <removed>(from local DNS server, may be cached)...
Note: A CNAME appeared in the results. Although technically valid for a CNAME to appear during an MX record lookup,
it is very unusual and not recommended (since CNAMEs are not allowed in two other cases during MX record lookups).

[pinterface]

Ah, I see from doing the research I should have done before posting, sendmail (possibly among other MTAs) rewrites domains with CNAME records to the domain the record points to. I also see one of the older mail RFCs (RFC 1123) effectively required this behavior.

Well, that's annoying. Ah well. Guess I'm in the wrong. Had to happen at some point. ;)

[jatar_k]

hehe

it was an interesting question all the same, made me ask myself the same question.