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OSSEC / HIDS Rule 171011
- Rule family: OSSEC / HIDS
- Rule ID: 171011
- Definition status: Present in current source
- Alert message / subject: SMTP Server rejected RCPT
- Rule level: 3
- Definition checked: 2026-10-21
Interpretation and response
This event is recorded as “SMTP Server rejected RCPT”. Review the originating log and the affected host or service to determine whether the activity was expected.
An OSSEC/HIDS event records or correlates activity. Blocking depends on the originating application and any separately configured Active Response policy; an alert alone does not prove that an attack was blocked.
Documentation
The following guidance was migrated from the historical wiki and reviewed against the rule definition. Legacy ASL product names and interface instructions refer to the versions documented then. Use the current metadata above and your installed configuration when interpreting thresholds, notification settings and response behavior.
Description
ASL does not cause this event to occur. ASL simply reports when your SMTP server has rejected an email message. ASL is not preventing your system from receiving this email. Please contact your mailserver vendor for assistance if you believe your mail server should not have rejected this message.
Disabling this rule will have no effect on your SMTP server rejecting these email messages. Disabling this rule will just prevent ASL from notifying you when this occurs, however the event will continue to occur. Therefore we do not recommend you disable this rule.
Log examples
2014-05-18 14:31:27 H=localhost (somehost) [192.0.2.10]:35234 F=<username@example.com> rejected RCPT <username@example.com>: Sender verify failed
Troubleshooting
False Positives
None.
Additional Information
Similar Rules
Source and revision
Migrated from HIDS_171011, wiki page 534, revision 4873 (20140518). Documentation review: 2026-10-21. An archived wiki status of Active is not a current deployment status.
For assistance, provide the rule ID, installed product and rule version, and a sanitized event to Atomicorp support .