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ipt_owner is now available

Posted: 11 Jan 2009, 20:58
by aaberr
OpenVZ kernels now have the module ipt_owner virtualized so using the SMTP_BLOCK should be possible for VPSes.

I did use a vps to connect to SMTP server of a shared hosting I have and sent mail successfully by cleancode.org email tool, after this I issued:

"iptables -I OUTPUT -p tcp --dport 25 -m owner --uid-owner root -j REJECT"

and the same command of the last test brought:

email: FATAL: Could not connect to server: ***.***.*** on port: 25: Connection refused
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Decision cannot be however made considering the Kernel version as according to OpenVZ forums there has been a time when Kernel supported the module but "vzctl" package did not. I would recommend just trying to add the needed rules and check for the exit code. Based on that, the user can be informed if SMTP_BLOCK would or would not work.

Updating the following thread is also suggested:

forum.configserver.com/showthread.php?t=212 (could not post url, less than 5 posts)

Posted: 14 Jan 2009, 21:59
by chirpy
Thank you for this information. I'll have to think of a way to allow the use of SMTP_BLOCK such that it doesn't cause confusion for those using either old versions or hosts that don't yet offer it.