One thing that might help is a spoof_sender_map, which says that
if the sender address is my.name@myisp.com, then the mail MUST arrive
via a myisp.com site

check_sender_access hash:/etc/postfix/spoof_sender_map

--<spoof_sender_map>--
my.name@myisp.com match_client_domain

--<spoof_client_map>---
myisp.com OK

--<strict_client.regexp>---
/@([^@]+)$/ 554 This mail didn't really come from a $1 system

--<main.cf>--
smtpd_restriction_classes = match_client_domain
match_client_domain = reject_unknown_client,
check_client_access hash:/etc/postfix/spoof_client_map,
check_sender_access regexp:/etc/postfix/strict_client.regexp,
reject

--
Greg


Jean wrote:
> Hello all,
>
> I often receive spams where the header looks like that:
>
> To: Jim Tiegal <my.name@myisp.com>
>
> "Ronal Tiegal" is not me but the name following it "<my.name@myisp.com>"
> corresponds to my real address. Is there a way with header_check or with
> the Postfix access file to filter these messages?
>
> Thanks
> Jean