Some links on SMTP tar-pit to lessen SPAM
Posted by jpluimers on 2021/11/03
Some links for my archive; note that pure tar-pits by now are also hampering large email sender services like SendGrid, Mailgun and Amazon SES.
So the below links are for educational and historic purposes only.
- Teergrube (Informationstechnik): SMTP Teergruben – Wikipedia
- Tarpit (networking): SMTP tarpits – Wikipedia
- [WayBack] Spam Filtering for Mail Exchangers
- Greylisting – Wikipedia
- Apache SpamAssassin – Wikipedia
- GTUBE (“Generic Test for Unsolicited Bulk Email”) – Wikipedia
I assembled these links because out of a sudden, Ring 2FA verification emails could not be delivered any more.
Ring 2FA came mandatory towards the end of February 2020.
Some links on that:
- [WayBack] Subdomain Finder scan of ring.com – C99.nl
- [WayBack] Ring in the changes: Mandatory two-factor authentication, login alerts, targeted ads opt-out after punters voice privacy gripes • The Register
- [WayBack] Ring doorbell makes two-factor verification mandatory – BBC News
- [WayBack] Enhancing Security with Two-Step Verification – Ring Help
- [WayBack] Two-Step Verification – Ring Help
- [WayBack] GitHub – dgreif/ring: Unofficial API for Ring Doorbells, Cameras, Alarm System, and Smart Lighting
- [WayBack] Two Step Verification now required for every login…? · Issue #256 · dgreif/ring · GitHub
The purpose of Two-Step Verification (2SV) is to protect you from bad actors logging into your Ring account, even if those bad actors have the proper login credentials. This feature will be enabled by default for all users and, unlike 2FA, there is no user option to opt out.
- [WayBack] Two Factor Auth · dgreif/ring Wiki · GitHub
- [WayBack] Two Step Verification now required for every login…? · Issue #256 · dgreif/ring · GitHub
Sendmail timeouts:
- [WayBack] ‘Timeout” ”” :: Chapter 24. The O (Options) Configuration Command :: Part III: The Configuration File :: Sendmail :: Server Administration :: eTutorials.org
- [WayBack] TUNING
- [WayBack] performance – Sendmail slow to accept emails – Server Fault
- [WayBack] centos – SMTP server takes 30+ seconds to accept a message, how to make it faster? – Server Fault
- [WayBack] Postfix manual – smtpd(8)
- [WayBack] Default SMTP IN and OUT Command Timeout Settings – SmarterTools
–jeroen
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2020-03-31T10:08:34.402372+02:00 snap sendmail[29592]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:10:05.550572+02:00 snap sendmail[30013]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:10:34.521709+02:00 snap sendmail[29592]: 02V88YAS029592: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:12:05.673585+02:00 snap sendmail[30013]: 02V8A5RQ030013: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:12:10.479557+02:00 snap sendmail[30057]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:13:31.911468+02:00 snap sendmail[30544]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:14:10.599326+02:00 snap sendmail[30057]: 02V8CAu4030057: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:14:40.481324+02:00 snap sendmail[30547]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:15:05.916150+02:00 snap sendmail[30549]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:15:32.033826+02:00 snap sendmail[30544]: 02V8DVFZ030544: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:16:40.604351+02:00 snap sendmail[30547]: 02V8EeRr030547: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:17:06.033592+02:00 snap sendmail[30549]: 02V8F5ZY030549: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:17:10.891192+02:00 snap sendmail[30595]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:17:40.447080+02:00 snap sendmail[30603]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:19:11.012476+02:00 snap sendmail[30595]: 02V8HAXM030595: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:19:40.569264+02:00 snap sendmail[30603]: 02V8Heh3030603: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:19:40.987599+02:00 snap sendmail[31105]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:21:08.069249+02:00 snap sendmail[31108]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:21:41.113096+02:00 snap sendmail[31105]: 02V8JeiK031105: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:22:40.174575+02:00 snap sendmail[31136]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:22:40.426572+02:00 snap sendmail[31137]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:22:40.919578+02:00 snap sendmail[31138]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:23:08.186602+02:00 snap sendmail[31108]: 02V8L8o4031108: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:24:40.295996+02:00 snap sendmail[31136]: 02V8Me0L031136: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:24:40.553121+02:00 snap sendmail[31137]: 02V8MeoI031137: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:24:41.042658+02:00 snap sendmail[31138]: 02V8MeN5031138: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:24:45.154333+02:00 snap sendmail[31622]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:26:45.275350+02:00 snap sendmail[31622]: 02V8OjB4031622: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:27:20.172571+02:00 snap sendmail[31643]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:27:40.905307+02:00 snap sendmail[31646]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:29:20.297002+02:00 snap sendmail[31643]: 02V8RKtX031643: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:29:41.026274+02:00 snap sendmail[31646]: 02V8Rea4031646: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:30:25.152770+02:00 snap sendmail[32193]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:32:00.519601+02:00 snap sendmail[32200]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:32:25.265366+02:00 snap sendmail[32193]: 02V8UPaR032193: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:34:00.646026+02:00 snap sendmail[32200]: 02V8W0ev032200: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:35:30.172349+02:00 snap sendmail[32716]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:37:00.906561+02:00 snap sendmail[32741]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:37:30.286290+02:00 snap sendmail[32716]: 02V8ZUQt032716: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:39:01.029903+02:00 snap sendmail[32741]: 02V8b084032741: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:44:55.825852+02:00 snap sendmail[1305]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:46:55.945400+02:00 snap sendmail[1305]: 02V8itAF001305: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:48:00.506257+02:00 snap sendmail[1337]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T10:50:00.627510+02:00 snap sendmail[1337]: 02V8m0vd001337: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T10:53:01.158286+02:00 snap sendmail[1886]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T10:55:01.291552+02:00 snap sendmail[1886]: 02V8r1Eg001886: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T11:01:02.131569+02:00 snap sendmail[3020]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T11:03:02.245406+02:00 snap sendmail[3020]: 02V912kf003020: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T11:19:00.525396+02:00 snap sendmail[5045]: NOQUEUE: connect from o7.sg.account.ring.com [149.72.233.225] | |
2020-03-31T11:21:00.650971+02:00 snap sendmail[5045]: 02V9J0Tm005045: o7.sg.account.ring.com [149.72.233.225] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA | |
2020-03-31T11:24:01.416265+02:00 snap sendmail[5594]: NOQUEUE: connect from o6.sg.account.ring.com [198.21.6.126] | |
2020-03-31T11:26:01.530327+02:00 snap sendmail[5594]: 02V9O1bx005594: o6.sg.account.ring.com [198.21.6.126] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA |
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