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- Nothing - Some mail domains will not get enough spam for us, or will not have thresholds set to block the tufts domain or we may be on their whitelist! and no action is taken
- Temporary Blacklisting - some mail services will place us on a brief hold anywhere from 24hrs to 4 weeks and then we are automatically allowed to email them again
- Time shift temporary blacklisting - This works similarly to temporary listing, but we're only blacklisted for a shorter period of time from the LAST spam event, so it may be 24 hours after the last spam event is recieved
- Blacklist single host some services will blacklist JUST the smtp relay that sent to them, which gives the impression that "some mail goes through, some doesn't"
- Blacklist via service - some recipient domains are members of trust organizations, that will monitor their receipts. Getting whiteliested or de-listed from those trust organizations will return service
- Blacklist via recipient domain - some recipient domains keep their own black-list or augment their trust organizations with their own list.
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Services to check if we are blacklisted:
1. http://MultiRBL.Valli.org
2. http://JustSpam.org
3. http://UnifiedeMail.net
4. http://BlacklistAlert.org/
Keep it Simple ways to check
Read the bounce messages, often it will be an error in the 500's sometimes 544, like the below example:
| Code Block |
|---|
> > SMTP error from remote mail server after initial connection:
> > host MX.nyu.edu [128.122.119.206]: 554-r1.home.nyu.edu
> > 554 Your access to this mail system has been rejected due to the
> > sending MTA's poor reputation. If you believe that this failure is in
> > error, please contact the intended recipient via alternate means.
> > |
Generally the next steps are to visit the recipient domain's website, contact their support desk or abuse@domain.com or postmaster@domain.com to try to find out what their de-listing process is.
Road to remediation
Most services simply make you submit a human-intervention request. Most services these days do NOT allow whitelisting.
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