From: Wietse Venema (wietseporcupine.org)
Date: Wed Jan 18 2006 - 07:46:39 CST

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lst_hoe01kwsoft.de:
> Hello
>
> we have a problem with our AV-Gateway (AntiVir Mailgate www.antivir.de)
> rejecting mail with "%" in the sender address.
>
> Jan 18 13:15:43 web postfix/qmgr[26578]: 004CF51DC2:
> from=<SRS0=PVEe=3O=k.st=jasonvor3%TEXT1%srs.kundenserver.de>,
> size=2968, nrcpt=1 (queue active)
> Jan 18 13:15:43 web postfix/smtp[7055]: 004CF51DC2:
> to=<xxxxxxkwsoft.de>, relay=10.5.0.2[10.5.0.2], delay=3,
> status=bounced (host 10.5.0.2[10.5.0.2] said: 553 Bad mail from address
> <SRS0=PVEe=3O=k.st=jasonvor3%TEXT1%srs.kundenserver.de: Expected a
> '>', not a LEXICAL ERROR (Invalid character (%) in address.) (in reply
> to MAIL FROM command))
> Jan 18 13:15:43 web postfix/qmgr[26578]: 004CF51DC2: removed
>
> The AV support claim that "%" isn't allowed in mail addresses and
> therefore the AV-Gateway is doing the right thing??

I suspect that it objects to the SECOND "%" character, because that
is not followed by a domain. The "%" is sometimes used as an
alternative "" character (user%domaindomain).

As far as Postfix is concerned this is a sender address in a remote
domain srs.kundenserver.de; therefore Postfix does not look at the
placement of %, or ! characters in the localpart.

Maybe `/%[a-z0-9_]+%/ reject spamware' can block this spamware
without loss of legitimate mail.

        Wietse

> If they are correct how can Postfix (Version 2.2.8) be configured to
> reject and if not where do i find the reference in the RFC.
>
> Thanxs
>
> Andreas
>
>
>
>

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