Source Routing and Sendmail

Unanswered Question
Mar 9th, 2008
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Hi all

This is probably not directly related to IronPort, but I'm sure you guys might be able to help.
We installed an IronPort applicane a few months ago and everything works great. Unfortunately, we forward the mails to our internal sendmail server which has to be reachable from the Internet for some legacy stuff. The sendmail box in conjunction with IronPort (smarthost) seems to enable source routing of email addresses, rendering the box an open relay.

Is there a way to drop all source routed e-mails at sendmail? Based on what I read, IronPort does drop source routed e-mails anyway.


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jaigill Mon, 03/10/2008 - 16:53
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  • Cisco Employee,

You will need to disable the loose_relay_check option in Sendmail. This option turns off the default behavior of rechecking recipients using the % addressing. For example, if the recipient address is user%[email protected], the default behavior without the loose_relay_check option is that Sendmail will check if any @othersite is an allowed relay host specified in either class R macro or the access db file. If a site is an allowed relay host, the check_rcpt ruleset strips @othersite and checks [email protected] for relaying. Sendmail does not recheck [email protected] if loose_relay_check option is set to ON.

cwling2008 Fri, 10/31/2008 - 09:10
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How to create virtual user table in ironport?


Alex Ling

Doc_ironport Sun, 11/02/2008 - 00:43
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How to create virtual user table in ironport?

You just use aliases. Aliases can be in basically the same form as the virtusertable entries in Sendmail. eg :

[email protected] [email protected] [email protected]

See the AsyncOS Users Guide for more examples.


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