Sendmail - Multiple Domains, One Box - Blocking One Or Two Domains

I have a number of domains hosted at a web hosting service. They use sendmail to handle incoming email. I have six domains on this service (which we can call aaa.com, bbb.com and so on). Each email account has the same name and one email box. In other words, tango@aaa.com, tango@ccc.com, tango@fff.com and all the others go into one box, /var/spool/mail/tango, where my email program on my desktop picks it up.

I have done very little work in sendmail. I haven't had to, and I've been warned it's a steep learning curve. But now I'm running into an issue. I was in a business situation where, for years, my email address was on the website for aaa.com. (We won't go into why this was necessary - it wasn't my preference and it's in the past.) Now I'm using tango@ddd.com instead of tango@aaa.com.

I was getting about 1,000 or more pieces of spam a day, but SpamAssassin and my own email program caught about 75% of that. (Which still left stuff to delete.) Now, after checking, I see that 90% or more goes to tango@aaa.com, the one that was on the web for years.

I'd like to deactivate tango@aaa.com and possibly tango@bbb.com and tango@ccc.dom, but want to keep using tango@ddd.com. Remember, email to tango at any of these domains will go into one email box.

I've had people tell me that sendmail can be configured so I can deactivate tango@aaa.com (and other domains) and still use tango@ddd.com (and others, if I want to). In other words, I can configure sendmail to use this account on some domains and not others. One of the people who was teling me this was in tech support at the hosting service.

But I wrote to tech support with a work order to do this and now I'm told it can't be done.

I can modify config files myself on this account if needed, but I was hoping to just let them do it. (I love delegation -- it means I spend more time doing my stuff.)

Is it possible to keep an email account active on one domain and not others with sendmail, when all domains are hosted on the same server? Is there a name for this process or setting? Any information would be helpful - either pointers to instructions so I can do it, or enough info so I can tell tech support, "This is where to look, and it can be done, so please pass my request on to someone who works with sendmail and knows how to do it."

Is this something sendmail can do?

Answer

You need to enable FEATURE(virtusertable) in your sendmail.mc. Next you have to execute three steps:

1. Rebuild sendmail.cf using the command appropriate for your operating
   system.



2. Next you need to edit your virtusertable with the following entries:

   
   
   

   tango@aaa.com error:550 user unknown
   




3. Rebuild the virtusertable database and restart sendmail. On Debian and Ubuntu systems this is done by executing sendmailconfig