CentOS4 MailScanner virtual users and webmail solutions

Drew Marshall drew at themarshalls.co.uk
Sat Mar 18 11:22:39 GMT 2006

On 18 Mar 2006, at 06:47, Dave wrote:

>   Hello,
> First of all thank you greatly for the rpm of MailScanner it  
> installed just fine on a CentOS4.x server.
> We've got an old sendmail box running on fc2 that we're going to be
> upgrading to postfix running on CentOS4. We host literally hundreds of
> domains, some with a single user others with multiple users.  
> Currently our
> sendmail setup has each user with a Unix account, needless to say our
> password files are huge. We don't have a lot of overlap between  
> usernames,
> i.e. we don't have two user1 users so currently that isn't an  
> issue. I'm
> wondering given our setup, which would be better virtual alias or  
> virtual
> mailbox domains?
> I'm leaning toward virtual mailbox, but would appreciate
> some practical experiences.

It all depends if you want Postfix to deliver the mail locally or  
forward it to another box for POP/ IMAP collection. If Postfix is  
doing the delivery then it's virtual mailboxes, if not then aliases.  
The difference is (Or should be!) in the map table mailboxes looks  
like user at domain	/domain/user(/) the trainling slash depends if you  
are using maildir or traditional unix mailboxes.

> In addition, a majority of our user's either get
> their mail via pop, i think now is the good time to add  
> authenticated smtp
> with tls for this, and others prefer a webmail solution.

Why not do both? If you base the POP/ IMAP and SMTP Auth around a  
MySQL database it's easy enough to maintain too.

> We use usermin, (I
> did not set that up) and i want to move away from this. I'm thinking
> squirrelmail, but am not sure if it'll work with our virtual  
> mailbox domains.

No problems with Squirrel mail with virtual domains. That bit is down  
to the IMAP server to sort out.

Have a look here http://www.gentoo.org/doc/en/virt-mail-howto.xml and  
here http://www.delouw.ch/linux/Postfix-Cyrus-Web-cyradm-HOWTO/html/ 
index.html for some ideas. While not written for CentOS you will get  
the idea :-)

One small gotcha to watch out for. You can't use virtual alias  
addresses in MailScanner as these are aliased by the Trivial Rewrite  
service, which happens before MailScanner sees the message. This  
means that if MailScanner tries to send mail to one of these users it  
will bounce as the alias hasn't been 'resolved' so there is no such  
user (e.g. warning notices go to postmaster at vdomain which is an alias  
for user at vdomain. The resolution from postmaster to user happens  
before MailScanner so if MailScanner sends mail to that address the  
Postfix delivery process doesn't know what to do with that message)


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