bsd.b3ta.org
Yet another *nix admin blog

I’ve been experimenting with numerous postfix features since Kaeru introduced me to this beast last year. One of them is Address verification. It is a feature that allows the Postfix SMTP server to block a sender (MAIL FROM) or recipient (RCPT TO) address until the address has been verified to be deliverable. The idea is to reject junk mail with an unreplyable sender address.

However, this feature is available in Postfix version 2.1 and later. The implementation is simple and clearcut.

CONFIGURATION

The following configuration is an example for Sender address verification for mail from frequently forged domains where selective domains were picked for address verification.

/usr/local/etc/postfix/main.cf

smtpd_sender_restrictions = permit_mynetworks,
    check_sender_access hash:/usr/local/etc/postfix/sender_access

/usr/local/etc/postfix/send_access:-

hotmail.com    reject_unverified_sender

Note : remember to hash the sender_access file with postmap and reload your postfix.

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It’s been a while that I didn’t make any update to my blog since I was quite occupied by LPI exam preparation and RawPacket LiveCD project development with geek00l. I will move this blog platform to wordpress for easy maintenance of the server. Stay tune for more updates or documentations on FreeBSD/Linux or even the LiveCD.

Symantec’s antivirus software has crippled thousands of Chinese PCs following virus definition update. According to Computerworld, the latest update for the AV component of the various Norton packages mistook two system files in the Chinese edition of Windows XP SP2 for the ‘Backdoor.Haxdoor’ trojan. With these files removed, Windows XP will no longer start up, and even the system Safe Mode no longer functions.

It seems that Antivirus and Virus are equally scary nowadays. Luckily, all client windows systems in my office are running English version of Windows XP SP2 else it is going to be a busy Monday for my colleagues and probably me too (helping out). This sux!