Weird things in the mail queue

Lionel Elie Mamane lionel at
Thu Feb 21 13:47:07 EET 2019

I noticed a mail stuck in my mail queue. dovecot-lda was returning
error 64 Invalid parameter given. (EX_USAGE).

Weird, weird, weird. After some sleuthing, I found the sender address
was FirstLast at domain.tld, with a UTF8-encoded Unicode U+FEFF ZERO
WIDTH NO-BREAK SPACE character (AKA byte order mark) between "First"
and "Last" :)

Since that is passed as the -f parameter to dovecot-lda, it was giving
the 64 error.

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