This is usually solved within your mta. In most simple setups, the MX server receiving the mails should not accept mails for which it is responsible itself, so your mailserver phyto.qc.ca should not accept mails with "from: any@phyto.qc.ca" from other servers than what you defined (e.g. in "mynetworks" if you are using postfix). On the other hand, you should make sure that your users cannot send their mails other than that linked to their accounts, so make sure joe@phyto.qc.ca cannot send as maria@phyto.qc.ca ... if you are using postfix, you might have a look at reject_sender_login_mismatch.

hope this helps,

infoomatic

Gesendet: Donnerstag, 14. April 2016 um 13:32 Uhr Von: Claude claude@phyto.qc.ca An: "dovecot@dovecot.org >> dovecot dovecot.org" dovecot@dovecot.org Betreff: How to filter spam with same to: and from: adress

Is it possible to create a filter somewhere to delete email that have same to: and from: adress. All these email are forged using my domain name with always different fictif user name. The only common point is that they have the same user name in the from: and to: adress

Claude Gelinas agr. Phyto Ressources Inc.