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E-mail Security Gateway

The e-mail security gateway scans all incoming e-mail for the presence of viruses. It also tries to determine if the e-mail is unsolicited commercial e-mail (spam) and marks it accordingly. The e-mail security gateway is one aspect of a comprehensive effort to provide enhanced network security. This effort includes protecting each computer with Sophos AntiVirus.

How it Works

All e-mails sent to the address are first sent through the e-mail security gateway before reaching the CCRI mail server. The gateway scans the e-mail for viruses and performs a number of tests to determine if the e-mail is spam. The disposition of the scanned e-mail is as follows.

If a virus is not found in the e-mail, the e-mail and any associated attachments are delivered as usual.

If a virus is found in the e-mail, both the attachment and the e-mail body are deleted from the e-mail system. The intended recipient will not receive these e-mails.

E-mail will not be delivered if the sender is found in a public blacklist. (Public blacklists are externally managed lists that include e-mail servers that are known to produce and/or promote spam.) The sender should receive the returned e-mail indicating that it could not be delivered and a reference to the blacklist.

E-mail that is determined to be spam based on the gateway’s antispam heuristics will have the words Possible Spam added to the subject line of the message. E-mail recipients can visually identify these messages and, if desired, filter them into a junk e-mail folder.

E-mail will not be delivered if its contents (including attachments) are larger than 25 MB. The sender should receive the returned e-mail indicating that it could not be delivered because the message is larger than permitted.

E-mail will not be delivered if it includes files that contain the following extensions: *.ad, *.ade, *.adp, *.asp, *.bas, *.bat, *.chm, *.cmd, *.com, *.cpl, *.crt, *.exe, *.dll, *.hlp, *.hta, *.inf, *.ins, *.isp, *.js, *.jse, *.lnk, *.mdb, *.mde, *.msc, *.msi, *.msp, *.mst, *.pcd, *.pif, *.reg, *.scr, *.sct, *.shb, *.shs, *.url, *.vb, *.vbe, *.vbs, *.vsd, *.vss, *.vst, *.vsw, *.ws, *.wsc, *.wsf, *.wsh.


If you have problems with or questions about the e-mail security gateway, please contact the IT Help Desk at 825-1112 or e-mail them at

This page developed and maintained by the Information Technology Department. Send comments and suggestions to .

Last Updated: 11/16/16