About
From time to time we (Tufts) spam the outside world when an account or accounts gets compromised. There are a number of outcomes that can result in the tufts mail domain being temporarily or permanently blocked from being able to send mail to recipient domains as part of this. This article describes some of them.
Different types of reactions from recipient domain
- 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.
Ways to check if we are blacklisted:
1. http://MultiRBL.Valli.org
2. http://JustSpam.org
3. http://UnifiedeMail.net
4. http://BlacklistAlert.org/
Road to remediation
Most services simply make you submit a human-intervention request. Most services these days do NOT allow whitelisting.
Permanent solutions
We could begin scanning our mail on outbound, but this can cause false positives of mail we don't allow to go out to skyrocket.