Re: I want to use ClamAV on one computer to scan mail received by Postfix on another computer

Maybe settig up a webserver can help, and post to the content of email 
when received to scan. I think this would work fine if you accept the 
email anyways or scan post receiving, and wont cause few seconds delay, 
also you might need to store attachments in files and include it in the 
post request to server.

On 2025-09-21 23:09, Paul Kosinski via clamav-users wrote:
> For many years now (well before Cisco's involvement) I have been 
> scanning email just before delivery by Postfix using procmail (not a 
> Milter). Up until now, I have been running ClamAV on the same computer 
> as Postfix, and scanning using clamdscan to stream (not fdpass) the 
> mail contents to clamd. (I do this using clamscan-procfilter.pl, 
> originally developed by A G Basile in 2004 and modified by me in 2007 
> and 2017.)
> 
> Unfortunately, ClamAV has changed so much from 0.103.x to 1.0.9 (not to 
> mention 1.4.3 and 1.5.0) that I can't currently run ClamAV in the same 
> OS environment as Postfix.
> 
> But I can't afford to have no email during the time that would be 
> needed to upgrade the OS, Dovecot, Postfix, Samba, etc. and test 
> everything on my current server. Nor can I afford to buy another 
> computer with similar power and storage (including software RAID0 and 
> redundant backup disks), set it up with new software versions, fully 
> test everything and then cut over almost atomically (as if that would 
> immediately work without problems).
> 
> So, what I am doing is setting up ClamAV on a small (but powerful) 
> computer and running clamd on it so as to receive the mail contents to 
> be scanned via a TCP port. (This might not be practical for a 
> commercial email service, but the email volume associated with home use 
> is pretty small.)
> 
> The problem I run into is that, although clamd.conf allows one to 
> specify a port number and even an an IP address for clamd to bind to, 
> there seems to be no way -- such as a command-line option -- to specify 
> what IP address clamdscan should talk to. (This makes the clamd binding 
> address almost irrelevant, I think.)
> 
> The only thing I can think of, other than modifying clamdscan's 
> internals (a possibly risky business), is to replace the regular clamd 
> on the Postfix computer by a trivial mechanism that simply listens on 
> localhost:3310 (for example) and forwards the TCP (via netcat or 
> xinetd) to the ClamAV computer running the real clamd which listens on 
> 10.23.45.67:3310 (for example).
> 
> Might there be a better way to do this? (I briefly thought of setting 
> up a VM or a "container" on the current server running Postfix et al, 
> and running the latest ClamAV therein, but that would still require a 
> quite disruptive upgrade of the software environment.)
> 
> Thanks
> Paul Kosinski
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