avast! mail shield and MS Exchange 2010 not playing nice...

Avast Business Avast Server Protection
1

We currently run a MS Exchange 2010 mail server with avast!. This server relays all outgoing e-mail to our ISP (Internet Service Provider), and we have for a long time (years) now been baffled by a very intermittent issue where our mail server would simply stop relaying e-mails for a few hours. Last week I discovered that the avast! mail-shield was the cause. When I disable the mail-shield, MS Exchange 2010 would happily relay our outgoing mail again. I tested this a few times - as soon as I enable the avast! mail-shield, an outgoing e-mail queue would build up, and as soon as I disable it, the outgoing e-mail in the queue would be relayed.

It seems that when the avast! automatically updates, certain updates add SMTP (Simple Mail Transfer Protocol) commands which are unrecognizable and the connection dropped. The errors in the logs show “Unrecognizable command “XXXXXXXX” - connection dropped”

I have had to disable the avast! mail-shield again. Can avast! please stop breaking our e-mail flow! Disabling the “Scan outbound mail (SMTP)” does not work either.

2

I’m having this same issue. It started the beginning of March out of the blue. Any help would be appreciated.
Dave

In the meantime I’ll keep looking for a solution.

3

We had the same issue but you’re not going to like the fix…

Boot server into safe mode, uninstall avast endpoint client- reboot normally … At this point our 2010 exhange agent was causing MS Exchange transport to start/stop- no mail flow.

Redeploy the avast endpoint client to the server and watch out for forced reboot! (Our server force rebooted, despite settings in console “Ask for reboot” so don’t try this during production hours)

After reboot, Exchange Transport now okay and Avast Exchange Shield now working as normal.

We think this happened to us after Windows updates to Exchange components (roll-up + antispam updates) but cannot say for certain.

Hope that helps.