How to reject spoofed mail

[Muralidharan_2]

Hi

I am using postfix as my SMTP server which is running in Redhat 8.0.I used most of the UCE features of postfix to stop spam mail and it is doing better job.But I want to stop spoofed mail completely coming to my server.

thanks
Muralidharan

[U.SivaKumar_2]

Hi,

Enable reverse lookup for connecting clients in postfix. Note that you will have run DNS servers with reverse zones for your own clients to connect properly to postfix.

edit /etc/postfix/main.cf
smtpd_client_restrictions = reject_unknown_client

To prevent spammers sending mail to your server with your sender address as your domain name from internet -

1) block mails from internet having sender domain as your domain.

2) To relay mails for your valid roaming users , who will have sender domain as your domain use authenticated relaying.

regards,

U.SivaKumar

[Steven E. Protter]

You can also go aol ballistic.

aol refused to accept mail from addresses that do not have valid reverse lookup records. A recent survery on my private servers show 75% of the inbound spam fails this test.

The problem is you'll need to use a sendmail hack and I have yet to figure out how to implement it.

Here is a copy of the hack and my thread which got no answers on how to implement it.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=450771

SEP

[Muralidharan_2]

Hi

Please give clear configuration for blocking mails from internet which having sender domain as my domain address

Regards

Muralidharan

[U.SivaKumar_2]

Hi,

Edit main.cf

smtpd_recipient_restrictions =
permit_mynetworks,
reject_unauth_destination
check_sender_access hash:/etc/postfix/sender

edit /etc/postfix/sender and put the below line

yourdomain.com DISCARD

#postmap /etc/postfix/sender

#postfix reload

regards,

U.SivaKumar