ClamAV outbound scanning: containing a compromised account

MxGuard Smarthost is a relay, not a spam filter — but it does run one important check on the way out: ClamAV virus scanning on every attachment.

Why it matters. The classic outbound disaster is a compromised account or an infected machine on your network suddenly blasting malware to your entire contact list under your good name. That single event can torch your domain's reputation and get your sending IP blocklisted for weeks.

What the scan does. Because your outbound mail passes through MxGuard, ClamAV inspects each attachment before it leaves. A message carrying known malware is stopped at the relay rather than delivered to your customers and partners.

This is a deliberate, light-touch measure: MxGuard does not apply the inbound spam models to your outbound mail (that would cause false positives on legitimate business correspondence), but virus scanning is universally safe and protects both your recipients and your sending reputation.