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

On Sun, 21 Sep 2025, Paul Kosinski via clamav-users wrote:
> 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.)

That is a surprise.
Over the years people have suggested running a dedicated clamav server
for all the machines in a network, bu like you I now cannot find any
documentation on how to tell clam to talk to a remote server.

This is probably a red-herring, but IIRC there used to be a third option
in addition to fdpass and streaming.

The Exim docs describe how to configure Exim to talk directly to a
(pool of) remote clamd server(s). Does Postfix have a similar option ?

> 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.)

-- 
Andrew C. Aitchison                      Kendal, UK
                    [email protected]
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