[Kolab-devel] [merge67] Introduce postfix helo checking

[Gelpi Andrea]

Fabio Pietrosanti wrote:
> New submission from Fabio Pietrosanti <fp at khamsa.ch>:
> 
> # Introduce helo checking (otherwise disabled by default)
> smtpd_require_helo = yes
> smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, 
> reject_invalid_hostname, reject_unknown_hostname, reject_non_fqdn_hostname
> 
> In this way a simple and useful antispam feature is added (without breaking anything)
> 

I tested the above configuration for quite a month and found that 
reject_unknown_hostname in Helo check has too much false positive. My estimation 
is about 30% to 40%.

Quite everybody who as more than one smtp server for sending, generate false 
positive. Lots of small society that use Win server generate false positive.

Some names that generate false positive:
Ras Group
Unicredit Bank
aruba.it
Vodafone

I disabled that control.

-- 
ing. Andrea Gelpi
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