2026-04-17 14:23:55
(2 months ago)
Apr 17 16:23:49 mx4 postfix/submission/smtpd[840718]: warning: unknown[66.56.81.91]: SASL PLAIN auth ...
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Apr 17 16:23:49 mx4 postfix/submission/smtpd[840718]: warning: unknown[66.56.81.91]: SASL PLAIN authentication failed:
Apr 17 16:23:55 mx4 postfix/submission/smtpd[840718]: warning: unknown[66.56.81.91]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
...
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Brute-Force
🇳🇱
Roderic
2026-04-17 13:28:35
(2 months ago)
*Port Scan* detected from 66.56.81.91 (CA/Canada/Ontario/Toronto/-/[redacted]).
Port Scan
🇬🇧
cg-design.co.uk
2026-04-17 13:00:02
(2 months ago)
(smtpauth) Failed SMTP AUTH login from 66.56.81.91 (CA/Canada/-)
Brute-Force
2026-04-17 10:27:48
(2 months ago)
16x Postfix SASL LOGIN authentication failed
Brute-Force
🇨🇿
lp
2026-04-13 01:51:06
(2 months ago)
Email account brute force: 5 attempts were recorded from 66.56.81.91
2026-04-13T02:58:53+02:00 warni ...
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Email account brute force: 5 attempts were recorded from 66.56.81.91
2026-04-13T02:58:53+02:00 warning: unknown[66.56.81.91]: SASL PLAIN authentication failed: authentication failure, [email protected]
2026-04-13T02:58:54+02:00 warning: unknown[66.56.81.91]: SASL LOGIN authentication failed: authentication failure, [email protected]
2026-04-13T02:58:55+02:00 warning: unknown[66.56.81.91]: SASL PLAIN authentication failed: authentication failure, [email protected]
2026-04-13T02:58:55+02:00 warning: unknown[66.56.81.91]: SASL LOGIN authentication failed: authentication failure, [email protected]
2026-04-13T02:59:02+02:00 warning: unknown[66.56.81.91]: SASL PLAIN authentication failed: authentication failure, [email protected]
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Brute-Force
🇺🇸
bigscoots.com
2026-04-13 01:01:24
(2 months ago)
(smtpauth) Failed SMTP AUTH login from 66.56.81.91 (CA/Canada/-): 5 in the last 3600 secs; Ports: 25 ...
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(smtpauth) Failed SMTP AUTH login from 66.56.81.91 (CA/Canada/-): 5 in the last 3600 secs; Ports: 25,465,587; Direction: 0; Trigger: LF_SMTPAUTH; Logs: 2026-04-12 21:00:53 dovecot_plain authenticator failed for H=([10.28.18.157]) [66.56.81.91]:10055: 535 Incorrect authentication data ([email protected] )
2026-04-12 21:00:59 dovecot_login authenticator failed for H=([10.28.18.157]) [66.56.81.91]:10055: 535 Incorrect authentication data ([email protected] )
2026-04-12 21:01:05 dovecot_plain authenticator failed for H=([10.28.18.157]) [66.56.81.91]:37626: 535 Incorrect authentication data ([email protected] )
2026-04-12 21:01:11 dovecot_login authenticator failed for H=([10.28.18.157]) [66.56.81.91]:37626: 535 Incorrect authentication data ([email protected] )
2026-04-12 21:01:23 dovecot_plain authenticator failed for H=([10.28.18.157]) [66.56.81.91]:46441: 535 Incorrect authentication data ([email protected] )
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Brute-Force
SSH
🇦🇺
jalim
2026-04-13 00:59:30
(2 months ago)
Fail2Ban (11cc81a08e1b): 3 attempts from 66.56.81.91 triggered postfix-sasl jail. Ban time: 3600s. A ...
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Fail2Ban (11cc81a08e1b): 3 attempts from 66.56.81.91 triggered postfix-sasl jail. Ban time: 3600s. Attack patterns detected in mail server logs.
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Brute-Force
2026-03-30 16:30:20
(2 months ago)
Failed login attempt detected by Fail2Ban in plesk-postfix jail
Brute-Force
2026-03-30 07:57:47
(2 months ago)
2026-03-30T00:57:37.250927-07:00 gremlin auth: pam_unix(dovecot:auth): authentication failure; logna ...
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2026-03-30T00:57:37.250927-07:00 gremlin auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=bradk7333 rhost=66.56.81.91
2026-03-30T00:57:46.424254-07:00 gremlin auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=bradk7333 rhost=66.56.81.91
...
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Brute-Force
SSH
🇩🇪
netclix.gr
2026-03-19 16:31:30
(2 months ago)
(mysaslmatch) Failed SASL login from 66.56.81.91 (CA/Canada/-): 2 in the last 4600 secs; Ports: *; D ...
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(mysaslmatch) Failed SASL login from 66.56.81.91 (CA/Canada/-): 2 in the last 4600 secs; Ports: *; Direction: inout; Trigger: LF_CUSTOMTRIGGER; Logs: Mar 19 18:31:24 anak postfix/smtpd[3393173]: warning: unknown[66.56.81.91]: SASL PLAIN authentication failed: authentication failure
Mar 19 18:31:25 anak postfix/smtpd[3393173]: warning: unknown[66.56.81.91]: SASL LOGIN authentication failed: authentication failure
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Port Scan
🇭🇺
Lacika555
2026-03-13 18:44:25
(3 months ago)
RdpGuard detected brute-force attempt on SMTP
Brute-Force
2026-02-27 14:20:20
(3 months ago)
Unauthorized connection attempt detected in the last 24 hours
Hacking
🇧🇷
hostseries
2026-02-25 03:53:17
(3 months ago)
Trigger: LF_DISTATTACK
Brute-Force
2026-02-11 12:33:54
(4 months ago)
Authentication failure
Brute-Force
2026-02-11 12:33:40
(4 months ago)
SMTP AUTH 66.56.81.91 (SMTP_LOGIN_ATTEMPT)
Brute-Force