This IP address has been reported a total of
5
times from
2 distinct
sources.
198.21.6.99 was first reported on
July 10th 2026 , and the most recent report was
3 days ago Switzerland
with 3
reports.
The only category in these recent reports was:
Email Spam
3
times.
Recent Reports
We have received reports of abusive activity from this IP address within the last week. It is
potentially still actively engaged in abusive activities.
Reporter
IoA Timestamp (UTC)
Comment
Categories
🇨🇭
Origon
2026-10-21 19:09:05
(3 days ago)
NOQUEUE - IP: 198.21.6.99 - Oct 21 21:09:05 plesk postfix/smtpd[2907354]: NOQUEUE: reject: RCPT fro ...
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NOQUEUE - IP: 198.21.6.99 - Oct 21 21:09:05 plesk postfix/smtpd[2907354]: NOQUEUE: reject: RCPT from o8.ptr6404.stsend5.io[198.21.6.99]: 554 5.7.1 Service unavailable; Client host [198.21.6.99] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=198.21.6.99; from=<REDACTED@REDACTED> to=<REDACTED@REDACTED> proto=ESMTP helo=<o8.ptr6404.stsend5.io>
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Email Spam
🇨🇭
Origon
2026-09-29 21:52:02
(3 weeks ago)
NOQUEUE - IP: 198.21.6.99 - Sep 29 23:52:02 plesk postfix/smtpd[3430735]: NOQUEUE: reject: RCPT fro ...
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NOQUEUE - IP: 198.21.6.99 - Sep 29 23:52:02 plesk postfix/smtpd[3430735]: NOQUEUE: reject: RCPT from o8.ptr6404.stsend5.io[198.21.6.99]: 554 5.7.1 Service unavailable; Client host [198.21.6.99] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=198.21.6.99; from=<REDACTED@REDACTED> to=<REDACTED@REDACTED> proto=ESMTP helo=<o8.ptr6404.stsend5.io>
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Email Spam
🇨🇭
Origon
2026-08-27 20:15:25
(1 month ago)
NOQUEUE - IP: 198.21.6.99 - Aug 27 22:15:25 plesk postfix/smtpd[2954999]: NOQUEUE: reject: RCPT fro ...
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NOQUEUE - IP: 198.21.6.99 - Aug 27 22:15:25 plesk postfix/smtpd[2954999]: NOQUEUE: reject: RCPT from o8.ptr6404.stsend5.io[198.21.6.99]: 554 5.7.1 Service unavailable; Client host [198.21.6.99] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=198.21.6.99; from=<REDACTED@REDACTED> to=<REDACTED@REDACTED> proto=ESMTP helo=<o8.ptr6404.stsend5.io>
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Email Spam
🇺🇸
EvilTurkey
2026-08-25 12:29:26
(1 month ago)
Sent an email which was automatically dropped by email firewall. Sending spam to financial instituti ...
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Sent an email which was automatically dropped by email firewall. Sending spam to financial institution.
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Email Spam
🇨🇭
Origon
2026-07-10 16:42:35
(3 months ago)
NOQUEUE - IP: 198.21.6.99 - Jul 10 18:42:35 plesk postfix/smtpd[1642866]: NOQUEUE: reject: RCPT fro ...
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NOQUEUE - IP: 198.21.6.99 - Jul 10 18:42:35 plesk postfix/smtpd[1642866]: NOQUEUE: reject: RCPT from o8.ptr6404.stsend5.io[198.21.6.99]: 554 5.7.1 Service unavailable; Client host [198.21.6.99] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=198.21.6.99; from=<REDACTED@REDACTED> to=<REDACTED@REDACTED> proto=ESMTP helo=<o8.ptr6404.stsend5.io>
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Email Spam
Showing 1 to
5
of 5 reports
