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Thread: Postfix mynetwork open relay
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- Join Date
- Jun 2012
Postfix mynetwork open relay
We have just setup a new postfix server to act as an antispam gateway in our network.
Under smtpd_recipient_restrictions, we have the following configuration:
mynetwork has the following values 127.0.0.0/8 and 192.168.0.0/24 which is the network subnet for the LAN.
According to this settings, the computer on the LAN, would be able to send emails even if they type an invalid
domain on RCPT TO as permit_mynetworks is before reject_unknown_recipient_domain.
But the thing is that with this settings, the server is acting as an open relay and all the computers out on the
Internet are able to relay mail through it (to domains that are not listed inside /etc/postfix/relay_domains).
If we remove the network segment for the LAN on mynetwork, then no computer is able to send email to the server.
I donīt know if is relevant, but we have a firewall with NAT to redirect the traffic on port 25 to the private IP of the server.
It would be great if someone could give us a hand or correct the configuration of the main.cf if there is something wrong
Thanks very much in advance
06-21-2012 #2linux user # 503963