The umich.edu mail relay servers block e-mail based on bad behavior by the sending host. Hosts both originating and relaying e-mail may be blocked.
Bad behavior may mean:
Sending mail with false sender information.
Sending mail to many invalid umich addresses.
Rapidly delivering a large volume of messages to a single mx machine, causing the load to spike and further connections to be rejected.
Virus Busters, after having found a flood of viruses from an incoming host, may also choose to block mail from that host.
To help reduce your incoming spam, see Using the Do Not Spam List to Reduce Spam.
To find out if a particular e-mail address, IP address, or domain is affected by the blocks listed above, use the E-Mail Block Status Check Tool.
Outgoing mail is blocked when it falls under the same categories of bad behavior for incoming mail.
See also E-Mail Filtering for Viruses
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General Computing | Contact Us | Computing on Campus | Wolverine Access | University of Michigan
October 12, 2009
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