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I have a recurring error message in my postfix logs regarding a malformed address in the RCPT command. presumably because of the questionmark characters (which originaly was a single "é" character.

postfix/smtpd[8315]: warning: Illegal address syntax from localhost[] in RCPT command: <addressee@dcm.caf??.com>

This has been recurring every minute for several days. I've tried restarting postfix, but it pops up again.

I am somewhat of a postfix newbie, so I'm not sure what I need to do. How do I get rid of it? and/or, Is this a problem?

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up vote 2 down vote accepted

"é" is part of the Extended ASCII Char set, not the base ASCII (ISO-8859-1 or ISO Latin1) character set so it needs to be properly encoded to be sent through postfix (or really any MTA)

It looks like the client that is trying to send mail isn't properly encoding the IDN(Internationalized Domain Name). Postfix doesn't support IDNs - SMTP is an ASCII only standard - encoding of the IDN to ACE (ASCII Compatable Encoding) is a client side issue, not a server side issue.

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Yes, I understand this part. How do I get rid of the message now it seems 'stuck' in the postfix system? – msharp Feb 25 '10 at 6:14
postfix should've rejected it instantly. If it didn't, find the queue ID in mailq and give it to postsuper -d. (I have a feeling some program of yours is constantly trying to send that message...) – grawity Feb 25 '10 at 13:06
thanks grawity, that seems to have been the issue, although I never got to the bottom of it. – msharp Mar 11 '10 at 4:27

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